TW202335971A - Microwave-processed, ultra-rapid quenched lithium-rich lithium manganese nickel oxide and methods of making the same - Google Patents

Abstract

A method includes sintering a lithium-rich metal oxide (LRMO) material at a sintering temperature to form a sintered LRMO material and quenching the sintered LRMO material from the sintering temperature to room temperature in less than 500 milliseconds to form a quenched LRMO material represented by a chemical formula Lix(MnyNi1-y)2-xO2, where x is greater than 1.05 and less than 1.25, and y ranges from 0.95 to 0.1.

Description

Microwave processed, ultra-fast quenching lithium-rich lithium manganese nickel oxide and its manufacturing method

Aspects of the present invention relate to cathode materials for lithium ion batteries, and more particularly, to lithium-rich lithium nickel manganese oxide cathode active materials, and methods of making the same.

Cobalt-containing cathode materials in lithium-ion batteries account for a large portion of the cost of contemporary battery cells, and cobalt is a key factor in that cost. Cobalt has supply chain complexities that make it a volatile commodity. Therefore, reliable cobalt-free lithium-ion battery cathode materials are needed.

According to various embodiments, a method includes sintering a lithium-rich metal oxide (LRMO) material at a sintering temperature to form a sintered LRMO material and quenching the sintered LRMO material from the sintering temperature to room temperature in less than 500 milliseconds to form A quenched LRMO material represented by the chemical formula Li _x (Mn _y Ni _1-y ) _2-x O ₂ , where x is greater than 1.05 and less than 1.25, and y is in the range of 0.95 to 0.1.

According to various embodiments, a method includes thermally decomposing a precursor material using microwave radiation to form a thermally decomposed lithium-rich metal oxide (LRMO) material, sintering the thermally decomposed LRMO material to form a sintered LRMO material, and quenching the sintered LRMO material to form a sintered LRMO material. A quenched LRMO material represented by the chemical formula: Li _x (Mn _y Ni _1-y ) _2-x O ₂ is formed, where x is greater than 1.05 and less than 1.25, and y is in the range of 0.95 to 0.1.

According to various embodiments, a cathode electrode active material is represented by the chemical formula: Li _x (Mn _y Ni _1-y ) _2-x O ₂ , wherein x is greater than 1.05 and less than 1.25, and y is in the range of 0.95 to 0.1. The active material contains layered hexagonal and monoclinic phases. The active material exhibits at least one of the following: (106)+(102):(101) x-ray diffraction peak intensity ratio greater than 0.32; when included in a lithium-ion battery, upon first discharge, at C/ Deliver at least 165 mAh/g specific capacity at C/20 rate; when included in such lithium-ion battery, have an average discharge voltage loss of less than 10% at C/20 rate after 100 charge/discharge cycles; and/or when When included in the lithium-ion battery, the attenuation is less than 10% of the capacity within 100 C/5 charge/discharge cycles.

Cross-references to related applications

This application is a continuation-in-part of U.S. Patent Application No. 17/810,722 filed on July 5, 2022, and claims U.S. Provisional Patent Application No. 63/296,243 filed on January 4, 2022, and 2022 Priority is granted to U.S. Provisional Patent Application No. 63/296,244, filed on January 4, 2019, the entire contents of which are incorporated herein by reference.

As set forth herein, various aspects of the invention are described with reference to exemplary embodiments and/or the accompanying drawings that illustrate exemplary embodiments of the invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the illustrative embodiments shown in the drawings or described herein. It will be appreciated that various disclosed embodiments may involve specific features, elements or steps described in connection with that particular embodiment. It will also be appreciated that, although described with respect to a particular embodiment, specific features, elements or steps may be interchanged or combined with alternative embodiments in various not illustrated combinations or permutations.

Various embodiments will be described in detail with reference to the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or similar parts. References to specific examples and implementations are for illustrative purposes and are not intended to limit the scope of the invention or claims.

Ranges may be expressed herein as from "about" one particular value, and/or to "about" another particular value. When indicating such a range, examples include from one particular value and/or to another particular value. Similarly, when a value is expressed as an approximation by use of the antecedent "about" or "substantially," it will be understood that the particular value forms another aspect. In some embodiments, the value of "about X" may include +/- 1% of the value of X. It will be further understood that each endpoint of each range is significant relative to, and independent of, the other endpoint.

According to various embodiments, a method for quickly and cheaply forming crystalline stable, highly durable, cobalt-free, lithium-rich metal oxide (LRMO) materials is provided. In some embodiments, the LRMO material may be a lithium-rich lithium manganese nickel oxide material represented by the following general formula 1: Li _x (Mn _y Ni _1-y ) _2-x O ₂ (Formula 1), where x is is greater than 1.0 and less than 1.25, and y is in the range of 0.95 to 0.1, such as about 0.8 to 0.5.

In some embodiments, the LRMO material may be a lithium-rich lithium manganese nickel oxide material represented by the following formula 2: Li[Li _(1/3-2x/3) Mn _(2/3-x/3) Ni _x ] O ₂ (Formula 2), where x is in the range of 0.1 to 0.4.

LRMO materials can have different hexagonal (eg, rhombohedral) and monoclinic phases in their original state (eg, before they are first charged). Therefore, the LRMO material can be represented by the following expression: (1-x)[Li ₂ MnO ₃ ] * x [LiMn _a Ni _(1-a) O ₂ ], where the first part of this expression represents the relative monoclinic phase The molar amount (1-x), and the second part of this expression represents the relative molar amount (x) of the rhombohedral phase. The mole fraction "x" of the rhombohedral phase typically ranges from 0.8 to 0.95, while "a" ranges from 0.6 to 0.9. In some embodiments, the two phases may be arranged in a layered structure.

Various embodiments provide LRMO materials that exhibit high (eg, >240 mAh/g) specific capacity and high functional voltage windows (eg, 2.0 to 4.8 V) when used as active materials for cobalt-free cathodes.

According to various embodiments, methods of forming LRMO materials include rapid thermal processing and fast (eg, less than 10 seconds) or ultra-fast (eg, less than 500 milliseconds) quenching, which results in excellent crystal structures with desired atomic order/disorder. LRMO material. These characteristics provide unexpectedly robust long-term stability and performance when used as cathode active materials.

Generally, conventional LRMO materials are not suitable for use as cathode active materials because of their low rate capacity and poor capacity retention, which are believed to be structurally unstable due to oxygen loss, migration of transition metal ions during use, and possible manganese dissolution. . The two most common aging mechanisms are the decay of the average discharge voltage as the material slowly reorganizes into a predominantly spinel structure, and the loss of capacity with cycling due to mechanical and/or chemical degradation of the material. Thermal decomposition and processing

LRMO materials can be synthesized from precursor materials through a variety of methods. Table 1 below includes specific methods that can be used to synthesize LRMO materials, including precursor synthesis, precursor materials, quenching methods, performance metrics, and discharge capacity (DC) of LRMO material cathodes. Table 1

As shown in Table 1, the three main synthesis routes for LRMO materials include precipitation, followed by combustion, hydrothermal synthesis and sol-gel solution generation, followed by medium-temperature decomposition and high-temperature thermal treatment (e.g., calcination, annealing, sintering).

As can be seen in Table 1, the number of studies exploring the impact of nickel composition on LRMO cathode performance has decreased over time; and few studies have explored the effect of Li[Ni _x Li( _1/3–2x/3 )Mn _{(2/3− x/3)} ]O ₂ various nickel compositions in the cathode or nickel compositions below x = 0.2. Table 1 also shows that there are significant inconsistencies in the synthetic routes used in the studies. Additionally, there are few studies that have performed detailed comparative evaluations related to the impact of synthesis methods on LRMO cathode performance. In LRMO materials, ordering and disordering of transition metals can be important, and both composition and synthesis techniques can provide mechanisms for affecting the degree of structural order and disorder. These compositional and synthetic changes can force electrochemical behavior, such as different defect concentrations, for example, which can have a significant impact on the properties of the LRMO cathode.

Without wishing to be bound by a particular theory, it is believed that when the sample is quenched in liquid nitrogen, the particles are immediately shielded by an insulating jacket of nitrogen, similar to the Leidenfrost effect, which significantly reduces the heat transfer rate. It is believed that in the prior art, lithium-containing cathode materials used in lithium-ion batteries were not in contact with moisture because water leach lithium from these cathode materials and form a lithium hydroxide coating on the materials. Additionally, water is known to cause failure in lithium-ion batteries, such as those containing lithium iron phosphate cathode materials.

Without wishing to be bound by a particular theory, the inventors believe that the relatively slow conventional quenching and cooling methods result in the accumulation of metal oxides, thereby forming separate nickel oxide and lithium manganese oxide phases. Specifically, the nickel oxide phase may be concentrated on the surface of LRMO material particles (eg, crystallites). It is believed that this surface nickel oxide accumulation is at least partially responsible for the chemical instability of conventional LRMO active materials.

In contrast, the inventors unexpectedly determined that water quenching does not adversely affect LRMO cathodes and does not cause lithium to leach from these LRMO cathodes. It is believed that water quenching causes vaporization in the form of bubble nucleation and dissipation, which actually increases the heat transfer rate. Therefore, it is believed that water quenching should have a heat transfer rate that is approximately two orders of magnitude greater than liquid nitrogen quenching. Additionally, both water and additives solvated therein (i.e., other materials soluble in water) can react with high-temperature LRMO upon its quenching to produce enhanced electrochemical stability and durability when used in lithium-ion batteries. Favorable surface termination and/or coating.

Additionally, in many of the prior art quenching approaches described above, quenching is performed on pressed sintered or partially sintered agglomerates of material as larger objects (e.g., having widths on the order of centimeters). complete. In contrast, in embodiments of the present invention, the quenching is performed on loose and/or ground powder having an average diameter of 20 microns or less, such as an average diameter of 0.1 to 20 microns, for example, 0.1 to 1 Micron or 1 to 20 micron particles in the shape of agglomerates such that when the particles come into contact with a quenching liquid (eg, water), all of the material cools quickly and at approximately the same rate. Each mass is composed of crystallites having an average size in the range of about 25 nm to about 500 nm, such as 50 nm to 200 nm. Each crystallite may comprise a single crystal of LRMO material. The crystallites may be partially fused with the mass or completely fused with the mass. If the microcrystals are completely integrated in the agglomerate (i.e., in the powder particles), then each microcrystal contains a single grain of the powder particle, which is formed by the grain boundary with other single grains in the same powder particle. separation. The powder particles may have an average grain size in the range of about 25 nm to about 500 nm, such as 50 nm to 200 nm. The agglomerates may be relatively porous, allowing water to reach the crystallites inside the agglomerate.

Fast and ultra-fast quenching

According to various embodiments, the LRMO cathode active material may be formed by thermally treating (eg, sintering, calcining, and/or annealing) and quenching the LRMO material powder. In particular, the thermal treatment may include a high temperature process in which the LRMO material may be heated to a processing temperature in the range of about 800°C to about 1000°C, such as in the range of about 850°C to about 950°C, or about 900°C. The heat treatment can be carried out in any suitable heat treatment device, such as a furnace, for example a tube furnace, a muffle box furnace, etc. In some embodiments, the thermal treatment may optionally include one or more low temperature precursor decomposition (eg, firing) processes in which the LRMO material is heated to a temperature above room temperature and below 800°C. For example, prior to the high temperature process, the firing may include heating the LRMO material to a temperature in the range of about 450°C to about 550°C, such as about 500°C.

According to various embodiments, the quenching method may include transferring the heated LRMO material to a quench bath. For example, the LRMO material can be dropped directly into the quenching bath from the heat treatment device.

In prior art methods, the LRMO material could be slowly cooled during transfer from the furnace. For example, the transfer process can take up to about 10 seconds, during which time the temperature of the LRMO material can slowly decrease. The inventors have determined that slow cooling prior to entering the quench bath can result in undesirable changes in the crystal structure of the sintered LRMO material. In other words, the temperature at which the sintered LRMO material enters the quench bath can be important in providing the desired crystal structure. For example, slow cooling can result in a less desirable crystal structure.

According to various embodiments, the transfer process may be configured such that the sintered LRMO material is at a temperature of at least 800°C, such as at a temperature in the range of 800°C to 950°C, or in the range of about 850°C to about 925°C, or After the sintering process at about 900°C, it enters the quenching bath. For example, the time of transfer from the thermal treatment device to the quench bath may be limited to 10 seconds or less, such as 1 second or less, such as less than 0.5 seconds, or 0.2 seconds or less. Accordingly, the sintered LRMO material is self-heating in 10 seconds or less, such as less than 0.5 seconds, including 0.2 seconds or less (e.g., from a sintering temperature of at least 800°C, such as between 800°C and 950°C, or a temperature in the range of about 850°C to about 925°C, or about 900°C) and cooled to room temperature (eg, 25°C). Herein, the "ultra-fast quenching method" may have a cooling time of less than 0.5 seconds, such as 0.2 seconds or less, such as 0.1 to 0.2 seconds, and the "rapid quenching process" may have a cooling time of 10 seconds or less, such as 0.5 seconds to 10 seconds Cooldown time in seconds.

The sintered LRMO powder particles may be quenched in a quench bath at an average rate of at least 50°C/second, such as 50°C/second to 10,000°C/second. For example, the sintered LRMO powder particles can be at a rate of 87.5°C/sec to 8750°C/sec, such as at least 1750°C/sec, such as 1750°C/sec to 8750°C/sec, including 4375°C/sec to 8750°C/sec. Quenching. Accordingly, the sintered LRMO material can be processed at a heat treatment temperature of at least 800° C. ( Quench at a temperature between, for example, the sintering temperature) and the temperature of the quenching bath (for example, a room temperature water bath at 25°C). For example, the quenching can occur between 100 milliseconds and 400 milliseconds, or between 100 and 200 milliseconds.

The quench bath may contain a high heat capacity liquid solvent having a vaporization temperature below about 200°C. For example, the quench bath may contain solvents such as water, oil, and/or alcohol. In some embodiments, the quench bath can include additives configured to modify the surface of the LRMO material during quenching to improve the long-term chemical stability of the material. The additive may include acid, alcohol, and/or dissolved carbon species, such as acid, alcohol, or carbon species dissolved in water.

For example, the quench bath may be an aqueous quench solution that includes about 0.01 to about 1.0 moles per liter, such as about 0.1 to 1.0 moles per liter, or about 0.5 to 1.0 moles per liter of an acid additive, such as sulfuric acid, hydrochloric acid, nitric acid , oxalic acid, citric acid, acetic acid, phosphoric acid, orthophosphoric acid, combinations thereof, or the like. The acid can be configured to stabilize the surface of the LRMO particles by reacting with and/or passivating dangling bonds and/or OH end groups of the LRMO powder particles quenched in water containing the acid additive.

In some embodiments, acid quenching can result in the formation of spinel structures (eg, surface layers) on the surface of the quenched LRMO powder particles. The spinel structure can form a framework that stabilizes the particles and provides a three-dimensional pathway for lithium diffusion. Specifically, it is believed that the acid can cause the Li ions of the particles to exchange with the H ions of the acid, and subsequent structural transformation of the surface of the particles, leading to the formation of a spinel surface layer.

In another embodiment, the quenching solution may include alcohol and/or carbohydrate additives in addition to or instead of acid additives. For example, the alcohol may include isopropyl alcohol or another alcohol, and the carbohydrate may include a sugar such as fructose, galactose, glucose, lactose, maltose, sucrose, combinations thereof, or the like. In some embodiments, the quenching solution may include about 0.01 to about 1.0 moles per liter, such as about 0.1 to 1.0 moles per liter, or about 0.5 to 1.0 moles per liter of the carbohydrate additive. The carbohydrates can form a dense amorphous carbon coating on the surface of the LRMO powder particles in the water containing the carbohydrate particles during the quenching process. The carbon coating may be permeable to Li ions but impermeable to the electrolyte of the Li ion battery. The carbon coating also allows the LRMO crystallites to change in volume during battery charging and discharging.

Fast or ultra-fast quenching methods can produce quenched LRMO materials with crystal structures that provide unexpected robustness and electrical properties. Specifically, the degree of crystalline order in quenched LRMO materials (e.g., lithium-rich lithium manganese nickel oxide) produced by the quenching process may provide a cathode suitable for use as a cathode similar to active materials including cobalt-containing, high-nickel content. Performance characteristics of cathode active materials for lithium-ion batteries based on energy density and charge storage stability characteristics.

The quenching method produces a quenched LRMO material powder with the desired crystal structure and particle size. For example, the quenched sintered LRMO material can be loose with an average particle size of about 1 µm or less, such as an average particle size in the range of about 0.02 µm to about 1 µm, or about 0.05 µm to about 0.5 µm. powder. In some embodiments, the quenched LRMO material may include crystalline phases and/or crystallites having an average crystal size in the range of about 25 nm to about 500 nm, such as about 50 nm to about 300 nm. Each powder particle may contain one crystallite or more than one crystallite. Loose sintered and quenched powder particles can be incorporated into a binder (eg, carbon binder) to form cathode electrodes for Li-ion batteries.

The LRMO material is dry-quenched to form an LRMO active material (eg, heat-treated and quenched loose powder particles) that may have a hexagonal primary phase and a monoclinic secondary phase. Therefore, the ratio of the hexagonal phase content to the monoclinic phase content is greater than 1, such as at least 2, for example 2 to 20. For example, a sintered and quenched LRMO material (eg, a dry active material) may have a superlattice structure including hexagonal primary phase layers separated by an intermediate layer of the monoclinic secondary phase. Alternatively, the sintered and quenched LRMO material may include a hexagonal phase substrate containing monoclinic nanoregions (ie, regions with a width less than one micron). Mn and Ni can be homogeneously distributed within the crystal structure of the LRMO material (for example, excess Mn, Ni and Li are homogeneously and evenly distributed on the transition metal lattice sites). For example, the crystalline grains of the sintered and quenched LRMO material show Mn and Ni atoms evenly distributed throughout the crystalline grains such that when imaged by high-angle annular dark field (HAADF) energy dispersive X-ray spectroscopy (EDS) (i.e., in In the EDS element distribution map of the HAADF tunneling electron microscopy image), there is no Ni-rich or Mn-rich region. In one embodiment, the term "no Ni-rich or Mn-rich regions" in the crystalline particles means that there is no crystalline volume larger than 3 x 3 x 3 nm in the crystalline particles, where the Ni and There is a difference of more than 3% between the average ratio of Mn atoms and the ratio of Ni and Mn atoms.

The crystal structure of the formed active LRMO material can be changed by electrochemical cycling. For example, when the active LRMO material is included as the active material in an electrochemical cell, the monoclinic phase may no longer be present at detectable levels after the first charge/discharge cycle. It is believed that this monoclinic phase can be consumed during Li ion insertion and/or selection.

rapid precursor breakdown

LRMO materials can be formed from a variety of precursor materials. For example, the precursor material may be a metal-organic compound including a metal, such as Li, Mn, and/or Ni, and a solubilizing agent, such as an organic ligand. For example, precursor materials may include metal acetates, metal carbonates, metal nitrates, metal sulfates, and/or metal hydroxides.

In various embodiments, the LRMO material may be formed by thermally decomposing a precursor material, followed by sintering and quenching the resulting thermally decomposed LRMO material. The precursor material may comprise a gel formed via a sol-gel process. The inventors have determined that rapidly decomposing precursor material gels can improve the homogeneity of LRMO materials. For example, in the sol portion of the sol-gel process, stoichiometric amounts of Li, Mn, and Ni-containing precursors can be mixed with water to form an aqueous mixture. For example, stoichiometric amounts of Li(CH ₃ COO)*2H ₂ O, Mn(CH ₃ COO) ₂ *4H ₂ O, and Ni(NO ₃ ) ₂ *6H ₂ O can be mixed to form an aqueous mixture. However, the invention is not limited to any particular precursor material. For example, in some embodiments, all acetate precursors or all nitrate precursors (ie, lithium nitrate, manganese nitrate, and nickel nitrate) may be used. In some embodiments, the mixture may include a 0.01 to 0.20 molar fraction excess of lithium acetate precursor to compensate for lithium losses during processing.

The mixture can then be heated to form a precursor gel. For example, the mixture may be heated at a temperature in the range of about 90°C to about 150°C, such as about 100°C, for a period of time sufficient for gelation to occur.

The gel can then be thermally decomposed. For example, the gel can be heated at a temperature and for a period of time sufficient to extract (eg, volatilize and/or decompose) the solubilizing agent, such as the organic ligand and/or solvent of the gel, and form a thermally decomposed LRMO material.

Thermal decomposition can be carried out using conventional furnaces such as muffle box furnaces and/or tube furnaces. However, these devices typically have slow heating and cooling rates of approximately 1 to 10°C per minute and do not use any type of direct radiant heat input. Therefore, conventional furnaces may require at least 8 hours of processing time and a large amount of energy to form thermally decomposed LRMO materials.

According to various embodiments, a rapid (eg, high rate) heating method is used to form the thermally decomposing LRMO material. For example, embodiments may utilize microwave radiation to thermally treat LRMO precursor materials (ie, to rapidly decompose LRMO precursors, such as gel precursors formed via sol-gel processes).

Microwaves are defined as electromagnetic radiation with a wavelength of 1 mm to 1 m. Widely used household microwave ovens use microwave radiation at a frequency of approximately 2.45 GHz. Regulations have limited the microwave frequencies that can be used in domestic and industrial applications. The mechanisms of microwave heating are classified into two categories: 1) the current under the external electric field generated by microwave radiation generates heat due to the Ohmic effect; and 2) the dipoles present in the ceramic reorient themselves under the changing electric field, generating heat due to friction .

Microwave heating allows lower thermal processing (eg, precursor thermal decomposition) temperatures. Compared with the conventional furnace heating method, microwave heating can also allow a shorter heating time due to very rapid local heating. Intimate mixing of precursor materials also allows for more efficient three-dimensional heating than conventional furnace heating methods.

In some embodiments, microwave heating is used to heat and decompose precursor materials and form thermally decomposed LRMO materials. For example, the precursor materials may include ligands and/or metals that are highly sensitive to microwave radiation. Accordingly, various embodiments utilize microwave radiation to heat precursors and/or precursor gels to extremely high temperatures in extremely short periods of time. It has also been found that microwave heating also provides highly uniform heat dispersion. Therefore, the use of microwave radiation can significantly change the heating rate and the resulting thermally decomposed LRMO material structure and/or structure. For example, microwave heating of precursor gels can lead to highly homogeneous thermal decomposition of LRMO materials. The thermally decomposable LRMO material may be in the form of an inorganic ash lacking organic components (eg, containing no carbon or containing unavoidable amounts of carbon). Therefore, microwave heating can allow the formation of thermally decomposed LRMO materials without the need for a separate furnace firing (which can be omitted).

For example, the precursor gel can be provided to a microwave oven, where microwave radiation is used to break down the gel and form a thermally decomposed LRMO material. For example, microwave radiation can be used to heat the gel to a temperature of at least 350° C. for a period of time sufficient to volatilize the gel's ligands and/or solvent and form the thermally decomposed LRMO material (e.g., LRMO inorganic ash). Such as a temperature in the range of about 350°C to about 500°C. In various embodiments, the LRMO material can be thermally decomposed in about 30 minutes or less, such as in about 15 to 30 minutes using continuous or pulsed microwaves with a power level of 20,000 W per kg of microwave material or less. form. Accordingly, microwave-based heating methods can be configured to rapidly remove (e.g., vaporize and/or burn) organic components from precursor species to form structures with improved structural properties, such as homogeneous cation and/or metal oxide distributions. ) of thermally decomposed LRMO materials.

Although the microwave thermal decomposition of the precursor gel formed by a sol-gel method is described above, in other embodiments, the precursor may be formed by other methods by microwave thermal decomposition. For example, alternative precursor preparation methods may include mechanical grinding/mixing methods, freeze-drying rotary evaporation, or co-precipitation methods. In one embodiment coprecipitation method, hydroxide precursors including Mn and Ni can be mixed with lithium carbonate and coprecipitated. For example, solid precursor materials including Li ₂ CO ₃ or LiOH, nickel oxide, and manganese oxide may also be used. These solid precursors may also have an excess of 0.01 to 0.20 molar fraction of a Li-containing precursor (eg, lithium carbonate or lithium hydroxide) to overcome the loss of lithium content during processing. Precursors prepared by any of these methods can also be subjected to microwave thermal decomposition to form thermally decomposed LRMO materials (ie, LRMO inorganic ash).

The thermally decomposed LRMO material (ie, LRMO inorganic ash) can then be mixed and ground (eg, milled) to form a precursor LRMO powder. The precursor LRMO powder is then thermally treated (eg, sintered) in any suitable thermal treatment device, such as in a furnace (such as a tube furnace, a muffle box furnace, etc.) to form a sintered LRMO material. For example, the precursor LRMO powder material can be heated (eg, sintered) at a thermal treatment temperature (eg, at least 800°C, such as a temperature of about 900°C) for a time period in the range of about 12 to about 24 hours, and then The sintered LRMO material is rapidly or ultra-fast quenched as described above to form a quenched LRMO material. The quenched LRMO material can then be dried and optionally reground (eg, ground) into LRMO active material (eg, active cathode material powder). This LRMO active cathode material powder can then be mixed with binders or other inactive cathode materials to form the cathode of a Li-ion battery.

According to various embodiments, methods of forming LRMO materials may include a combination of rapid heating (such as microwave heating) for at least a portion of the thermal treatment combined with rapid or ultra-fast quenching to produce LRMO materials with unexpectedly high performance. Specifically, this method can produce LRMO materials with a high degree of atomic/cationic disorder/homogeneity (which can be quantified using X-ray diffraction), along with the absence or substantial absence of nickel or nickel oxide in the particles (e.g., crystallites) Surface segregation can be observed using transmission electron microscopy. This combination of material properties results in cathode active materials that exhibit little to no capacity fading over 100 to 1000 charge/discharge cycles, average discharge voltage during cycling is substantially reduced or eliminated, and rate capacities suitable for commercial use.

According to various embodiments, embodiment methods including microwave heating and/or fast/ultra-fast quenching steps may be used to form LRMO active materials that are not affected by the chemical instability of prior art LRMO materials. In particular, this fast or ultra-fast quenching step can be used to form LRMO active materials with reduced Ni surface segregation and increased structural homogeneity compared to conventional LRMO materials that are slowly cooled after sintering. In various embodiments, the above microwave heating methods can be used in conjunction with fast or ultra-fast quenching to form LRMO active materials. For example, thermally decomposed LRMO materials formed using microwave decomposition can be sintered and then subjected to fast or ultra-fast quenching methods.

In one embodiment, the cathode electrode (ie, the positive electrode) includes an LRMO active material including powder embedded in a binder. The powder may have an average particle/agglomerate size in the range of about 0.1 µm to about 10 µm and an average crystal (ie, crystallite) size in the range of about 25 nm to about 500 nm. In one embodiment, particles of the LRMO active material powder may have a spinel surface layer, a carbon coating (e.g., resulting from carbohydrate additives in the quench bath), and/or passivated oxygen bonds on the surface (e.g., from At least one of the acid additives in the quenching bath). The cathode electrode may be included in a battery, such as a lithium-ion battery, which also includes an anode electrode (ie, a negative electrode), an electrolyte, and a separator.

In one embodiment, the cathode electrode active material may be represented by the chemical formula Li _x ( _Mny Ni _1-y ) _2-x O ₂ , where x is greater than 1.05 and less than 1.25, and y is in the range of 0.95 to 0.1. At least before the first electrochemical cycle of the cell containing the cathode electrode, the active material may comprise layered hexagonal (eg, rhombohedral) and monoclinic phases. The active material may exhibit at least one of: (i) greater than 0.32, such as 0.33 to 0.346 of (106)+(102):(101) x-ray diffraction peak intensity ratio; and/or (ii) greater than 2 , such as a (003) to (104) x-ray diffraction peak ratio of 2.01 to 2.575; and/or (iii) when the cathode electrode is included in a lithium-ion battery, delivered upon first discharge (e.g., at a C/2 rate) At least 200 mAh/g, such as 200 to 230 mAh/g specific capacity; and/or (iv) when the cathode electrode is included in the lithium ion battery, the lithium ion battery after 100 charge/discharge cycles at C/20 exhibit a loss of less than 10% of the average discharge voltage at the rate; and/or (v) when included in the positive electrode of the lithium-ion battery, for at least 100 charge/discharge cycles, such as 200 C/5 charge/discharge cycles Less than 10%, such as less than 5% capacity decay over the cycle (eg, 0 to 4% capacity decay or capacity gain). In one embodiment, the lithium-ion battery may include lithium or graphite as the anode electrode.

In one embodiment, the average discharge voltage of the battery (e.g., lithium-ion battery) decreases by no more than 5% (e.g., 0 to 4%); and/or the discharge capacity of the battery is greater than 80% of its initial capacity after 800 C/20-C/2 charge/discharge cycles. Experimental examples

LRMO powders with the formula Li _x (Mn _y Ni _1-y ) _2-x O ₂ (where x = 1.16 and y = 0.7) were produced using the following method. Specifically, the precursor material gel is produced using a sol-gel solid state synthesis method. The synthesis of the sol involves forming an aqueous mixture including stoichiometric amounts of Li( _CH3COO )* _2H2O , Mn( _CH3COO ) ₂ * _4H2O and Ni( _NO3 ) ₂ * _6H2O . The mixture was heated at 100°C until a gel formed. The gel was poured into an alumina crucible and then fired at 400°C for 90 minutes, producing an organic-poor ash. The resulting ash was ground and refired in the crucible at 500°C for 3 hours and then allowed to cool naturally before regrinding. The powder was then sintered at 900°C for 24 hours and then quenched. All sinterings were performed in a box furnace under ambient fume hood conditions. All quenchings are performed after heating at 900°C for 12 to 24 hours.

Figure 1 is a photograph of a rapid quenching system 100 according to various embodiments of the present invention. Figure 2 includes four consecutive video capture time-lapse images taken at 30 frames per second showing the rapid quenching process in accordance with various embodiments of the present invention.

Referring to Figures 1 and 2, the LRMO material is provided to a tube furnace 110 where the material is heated to 900°C. The heated LRMO material is output from the tube furnace 110 and quenched to room temperature in the quenching bath 120 . The tube furnace 110 rotates during operation such that its contents are immediately dumped into the quench bath 110 . The time period between the time the LRMO material leaves the furnace 110 at 900°C and the time required to quench it to room temperature is less than 500 milliseconds, such as less than 200 milliseconds to form the LRMO active material. After quenching, the LRMO material is filtered from the water in the quench bath 120 and dried in a vacuum oven.

In a first comparative example, after sintering at 900°C, the LRMO material was allowed to cool slowly in the furnace 110 . In a second comparative example, the LRMO material was cooled by pouring onto a metal plate after sintering. In a third comparative example, the LRMO material is first slowly cooled to room temperature and then embedded in the tube furnace 110 for an ultra-fast quenching step, where it is maintained at 900°C for 30 to 120 minutes before the ultra-fast quenching step. .

In an alternative example, a rapid precursor decomposition method is used to form LRMO powder. Specifically, microwave radiation is used to decompose the sol-gel precursor material described above to form an LRMO powder with an improved component distribution. In particular, application of microwave radiation results in rapid evaporation of the organic components of the precursor materials because the organic components absorb microwave energy. Therefore, the LRMO components are homogeneously mixed at the molecular level due to the thermal energy generated by this microwave radiation. The resulting LRMO powder was then sintered at 900°C for between 12 and 24 hours and then ultra-fast quenched as described above.

Multiple larger batches (up to 1 kg) of cathode material were produced both with and without microwave decomposition and ultra-rapid quenching. Material characterization

Figures 3 and 4 are X-ray diffraction (XRD) patterns of Li _x (Mn _y Ni _1-y ) _2-x O ₂ materials (where x = 1.2 and y = 0.75) according to various embodiments of the present invention. Figure. The XRD spectrum in Figure 3 was generated from the layered LRMO active material that was not rapidly quenched by immersion in water, while the XRD spectrum in Figure 4 was generated from the layered LRMO active material that was quickly quenched by immersion in water.

Evaluation of XRD patterns shows that the LRMO material has the expected hexagonal (e.g., rhombohedral) phase LiNiO ₂ associated space group (R-3m) and the monoclinic phase (Li ₂ NiO ₃ associated space group (C2/c)).

Figure 5 shows Li _x (Mn y Ni 1-y ) 2-x O 2 material (Mn _y Ni _{1-y ) 2-x O 2 material (Mn y Ni 1-y ) 2-x} O ₂ material ( A diagram of the X-ray diffraction results for x = 1.16, and y = 0.7). Referring to Figure 5, the main focus is on the fact that this microwave-decomposed material has a resulting x-ray diffraction pattern consistent with a highly crystalline and optimized material, including the space group (R-3m) associated with the rhombohedral phase _LiNiO The space group (C2/c) related to the oblique phase Li ₂ NiO ₃ . Therefore, as described above, this material is suitable for LRMO formation using 900°C annealing and fast and/or ultra-fast quenching.

Figure 6 is a diagram illustrating Li _x (Mn _y Ni _1-y ) _2-x O ₂ material (where x = 1.16 and y = 0.7) using microwave heating and ultra-fast quenching according to various embodiments of the present invention. Diagram of X-ray diffraction results. Referring to Figure 6, all expected peaks are present and well defined.

Figure 7A is a reference from a tunneling electron microscopy (TEM) high-angle annular dark field imaging (HAADF) atomic image micrograph of a typical LRMO material that has not undergone rapid quenching before electrochemical cycling (H. Zheng et al. , "Recent developments and challenges of Li-rich Mn-based cathode materials for high-energy lithium-ion batteries", Materials Energy Today, Volume 18, December 2020, Page 100518) prior technology examples. As can be seen from these micrographs, the initial LRMO material has significant segregation of nickel and manganese inside the particles.

Figure 7B is a TEM HAADF atomic image micrograph of a produced LRMO material subjected to rapid quenching prior to electrochemical cycling of the material in accordance with various embodiments of the present invention. As can be seen from these micrographs, the LRMO material has no obvious nickel/manganese segregation in the particles. Therefore, rapid or ultra-rapid quenching reduces or eliminates nickel segregation on the surface of the particles, and nickel and manganese are evenly mixed in the bulk of the LRMO material. Crystal uniformity, cation disorder and surface passivation

One way to assess the degree of disorder of metal cations in a material is to use the ratio of peak intensities in x-ray diffraction patterns. Specifically, the ratio of the intensity of the (003) peak to the (104) peak is often referred to as a rough measure of the electrochemical activity in mixed cationic materials with this predominantly layered crystal structure, while the ratio of the intensity of the (006) and (102) peaks is The ratio of the sum to the intensity of the (101) peak is an indicator of cation disorder. Based on this, materials that have been microwaved and then ultra-rapidly quenched during the decomposition phase provide significantly higher indications of electrochemical activity and a lower degree of cationic ordering (and therefore a higher degree of cationic disorder) than slowly cooled materials. . Table 2 XRD peak ratio (003)/(104): The higher the value, the greater the electrochemical activity. [(006)+(102)]/(101): The higher, the higher the cation mixing/disorder Comparative example: slow cooling 2.79 0.318 Example: Ultra-rapid quenching 2.575 0.346

Table 2 shows XRD peak intensity ratios for a comparative example LRMO material subjected to slow quenching after sintering (row 1), and an exemplary LRMO material subjected to ultra-rapid quenching after sintering (row 2). Both materials have the formula Li _x (Mn _y Ni _1-y ) _2-x O ₂ , where x = 1.2 and y = 0.75. Importantly, the exemplary ultra-fast quenched materials exhibit XRD characteristics that indicate atomic freedom in the materials with significantly higher electrochemical activity and greater cationic disorder/metal oxide homogeneity than the comparative example materials. Serialization increases. Specifically, the exemplary materials show an increase in the ratio of the sum of the intensity of the (006) and (102) peaks to the intensity of the (101) peak, in this case about 9%. This significant increase in cationic disorder represents a situation in which the Ni and Mn atoms are more completely mixed (and therefore not grouped) in the material. For this reason, this exemplary material may be referred to as "cationically disordered lithium-rich lithium manganese nickel oxide," and these data demonstrate that differences can occur based on the processing conditions used and, in particular, the cooling rates used. state of matter. Electrochemical testing

A suitable cathode material is mixed with Super-P carbon black and polyvinylidene fluoride (PVDF) in a ratio of 8:1.2:0.8 so that the active material accounts for 80% of the total mass. The resulting blend was then mixed into ~15 ml N-methyl-2-pyrrolidinone for a minimum of an hour before two 10 minute sonicating steps, and the resulting slurry was further allowed to cool on a hot plate at 100 Mix at 100°C for a minimum of 30 minutes, then spray onto 10x10 cm, 10 µm thick aluminum foil heated to above 100°C. The foil was allowed to dry in air in a 70°C oven overnight and then punched with a biopsy punch. These punches were then used to fabricate 2032 coin cells using lithium foil as the anode, 1.0 M LiPF ₆ 50/50 ethylene carbonate/dimethyl carbonate solution as the electrolyte, Celgard cell separators, 0.5 mm stainless steel spacers, and wave springs on the cathode side to ensure mechanical contact within the cell; each coin cell is assembled and sealed by using a coin cell press in a dry, low-oxygen argon atmosphere.

Electrochemical performance studies use low-current Neware or bio-logic battery testers to conduct potential-limited galvanostatic tests at constant current on coin-type batteries manufactured in the method described above. The cells were cycled using constant current charge/discharge conditions at a rate ranging from C/20 to C/2 between 4.8 and 2 V.

Figure 8A is a graph showing cell potential versus specific capacity, and Figure 8B is a LRMO material (Li _x (Mn _y Ni _1-y ) without microwave treatment or rapid quenching (in this case relatively slow cooling on a metal disk) Plot of specific capacity versus circulation for the comparative example of _2-x O ₂ , where x = 1.16, and y = 0.7).

Referring to Figures 8A and 8B, it can be seen that the slowly cooled material has poor capacity and capacity retention. After 50 full charge/discharge (C/2 rate) cycles, the material produced a specific capacity of 120 mAh/g at the C/20 rate, which is well below the material's theoretical performance. In addition, there is significant voltage decay in this material, with the average discharge potential being below 3 V after 30 cycles.

Figure 9A is a graph showing battery potential versus specific capacity during a break-in cycle of ultra-rapid quenching materials, Figure 9B is a graph showing cell potential versus specific capacity over time for ultra-rapid quenching materials, and Figure 9C is a graph that includes a battery according to the present invention. Exemplary cells of various embodiments of LRMO active materials, showing a graph of specific capacity versus cycle over multiple cycles at C/20 rate. Figure 9D is a long-term cycle of an exemplary LRMO material showing that over 150 C/5 cycles, the material exhibits less than 10% capacity for all three C/20 reference cycles (which occur at cycles 56, 107, and 158) Attenuation.

In contrast to the comparative exemplary materials shown in Figures 8A-8B, the exemplary LRMO cathode materials fabricated using ultra-rapid quenching performed well as shown in Figures 9A-9C. The electrochemical performance data in Figures 9A and 9B demonstrate both that: (a) highly functional materials can be produced at a meaningful scale, and (b) these materials have performance properties that match or exceed those produced in much smaller batches. It should be noted that the voltage profile has a clear and desirable inflection after a discharge capacity of approximately 100 mAh/g compared to materials made using slower cooling methods. Voltage traces above this inflection point demonstrate that there are almost no "sags" or losses during cycling, an improvement compared to materials made using slower transfer techniques. This demonstrates that an ultrarapid cooling method using gravity-driven transfer from the furnace to the quenching environment in 200 milliseconds is ideal when combined with microwave irradiation and rapidly decomposing precursors.

_Figure 10A shows _{the cell potential vs.} A graph of specific capacity. Figure 10B shows a graph of specific capacity versus cycle number for the battery of Figure 10A. Figure 10C shows a graph of the battery without ultra-fast quenching (the material was removed from the furnace environment and not quenched within a few seconds). Exemplary cells of water-quenched LRMO active material (Li _x (Mn _y Ni _1-y ) _2-x O ₂ , where x = 1.16 and y = 0.7) cells at first and 50th C/2 discharge cycles A graph of potential versus specific capacity, and Figure 10D is a graph showing the specific capacity versus cycle number of the battery of Figure 10C. Both active materials were not microwaved.

Both the comparative and exemplary cells were cycled twice with charge and discharge current at a rate of approximately C/20 to condition the cathode material. Thereafter, 25 cycles were performed at a charging rate of C/20 and a discharging rate of C/2. This set of 27 cycles is called a cycle, and all batteries undergo this program twice. As can be seen in Figures 10A-10D, the rapidly quenched exemplary materials have improved capacity and capacity retention relative to the comparative materials. After 50 full charge/discharge cycles, the exemplary material produced a specific capacity of nearly 230 mAh/g at a C/2 rate, which was far superior to the comparative material, which showed much lower capacities and lower the average discharge voltage. Accordingly, this exemplary material, a) displays a significant increase in capacity over 50 cycles, (b) does not exhibit the commonly reported excess voltage fade (wherein the average discharge voltage of the cell is significantly reduced over use), and (c) Exceeds 250 mAh/g at C/20 discharge rate after 1 cycle and 230 mAh (at C/2 rate) after 50 cycles, and the average voltage loss during discharge is less than 10%. The specific capacity increases by 20 to 25% over 50 full C/20-C/2 charge/discharge cycles. In contrast, the comparison material had much lower performance, including a specific capacity value of less than 100 mAh/g.

Figure 11A shows the cell potential and specific capacity of an exemplary cell including microwave decomposed and rapidly quenched Li _x (Mn _y Ni _1-y ) _2-x O ₂ active material where x = 1.16 and y = 0.7 , and FIG. 11B are graphs showing specific discharge capacity versus cycling at C/20 and C/2 rates for the exemplary battery of FIG. 11A , in accordance with various embodiments of the present invention.

Thus, as shown in Figures 11A-11B, combining microwave decomposition methods with rapid thermal quenching results in materials that provide even more electrochemical stability. Compared to the comparative cell materials, the combined microwave treatment and rapid quenching method produced a greatly reduced voltage sag and a stable discharge capacity for ~200 cycles (at which point the coin-type battery test jig used failed).

The synthesized LRMO active material (i.e., sintered and quenched loose powder) is mixed with Super-P carbon black and polyvinylidene fluoride (PVDF) at a ratio of 8:1.2:0.8 so that the active LRMO accounts for 80% of the total mass. The resulting blend is then mixed into approximately 15 ml of N-methyl-2-pyrrolidone for a minimum of one hour. Two 10-minute sonication steps were then performed, and the resulting slurry was further allowed to mix on a hot plate at 100°C for a minimum of 30 minutes before being sprayed onto 10 x 10 cm, 10 μm thick aluminum foil heated to above 100°C. The foil was allowed to dry in air in a 70°C oven overnight and then sampled into circular electrode disks. The resulting punch was then used to fabricate 2032-type coin cells, which included lithium foil anodes, 1.0 M LiPF6 50/50 ethyl carbonate/dimethyl carbonate solution as the electrolyte, Celgard cell separators, and 0.5 mm stainless steel spacers. , and a wave spring on the cathode side to ensure mechanical contact within the cell. Each coin cell was assembled and sealed using a coin cell press in a dry low-oxygen argon atmosphere.

A LAND battery tester was used to conduct a potential-limited galvanostatic test at a constant current on the coin-type battery manufactured in the method described above. A minimum of three cells per variant were cycled at ambient temperatures between 2.0 V and 4.8 V. The battery is cycled twice with charge and discharge current at a rate of approximately C/20 to condition the cathode material. The batteries were then charged and discharged for 25 cycles at a C/20 charge rate and a C/2 discharge rate. These 27 cycles can be called one cycle, and all batteries undergo two cycles.

Figure 12A shows the results of the x = 0.25 sample (ie, Li[Ni _x Li( _1/3–2x/3 )Mn _(2/3−x/3) ]O ₂ sample, where x = 0.25) during the cycle. Graphs of specific discharge capacity, and Figures 12B to 12D show the full charge and discharge curves of coin-type batteries including 25Hq, 25Lq and 25Mq samples respectively. Figure 13A is a graph showing the specific discharge capacity of the x = 0.17 sample during cycling, and Figures 13B to 13C show the full charge and discharge curves of coin-type batteries including the 17Hq, 17Lq and 17Mq samples respectively. Figure 14A is a graph showing the specific discharge capacity of the x = 0.10 sample during cycling, and Figures 14B to 14C show the full charge and discharge curves of coin-type batteries including 10Hq, 10Lq and 10Mq samples respectively.

Table III below shows the discharge capacity (DC) of the samples during cycling, together with the C/20:C/2 ratio of DC28/DC27. The rate capability is evaluated by taking the ratio of C/20 discharge capacity to C/2 discharge capacity, such as the discharge capacity at the 27th and 28th cycles. Note that discharge cycles 1, 2, and 28 are at the C/20 rate, while discharge cycles 3, 27, and 54 are at the C/2 rate. Table III

Referring to Figures 12A to 12C, x = 25 samples synthesized with different quenching methods show different relative implied charge capacities in their first charge 4.5 V platform. Specifically, the 25Hq platform accounts for 60.7% of the initial charging capacity, the 25Lq platform accounts for 44.4% of the proportional capacity, and the 25Mq platform only accounts for 34.5% of the proportional capacity.

In the x = 0.25 sample, 25Hq has the highest initial capacity of 186 mAh g ⁻¹ and 25Mq has the lowest initial capacity of 127 mAh g ⁻¹ . As can be seen in Table III, improved capacity was seen during cycling for all x = 0.25 samples except the 25Mq sample. The maximum capacity increase for all three samples was seen at 25Hq. The 25Mq sample also showed severe voltage decay, with the voltage dropping to less than 3 V during cycling. Although the 25Hq and 25Lq samples also have an inflection point at 2.8 V on their iso-discharge curves, their iso-discharge curves do not show such severe voltage attenuation. This voltage decay was not seen in the C/20 discharge of the 25Hq and 25Lq samples, however the C/20 discharge of the 25Mq sample experienced voltage decay. The average discharge voltage of the 0.25 sample reflects these voltage attenuation, and 25Mq has the lowest average voltage during cycling, and 25Lq has a slightly higher average discharge voltage than 25Hq.

Regarding the rate capacity, as can be seen in Table III, the C/20:C/2 ratios of the 25Hq, 25Lq and 25Mq samples are 1.19, 1.25 and 1.39 respectively.

Referring to Figures 13A to 13D, the charging profile of the x = 0.17 sample has a more classic single flat 4.5 V plateau on first charge, which accounts for approximately 56.8% of the initial charge capacity, while the 17Lq and 17Mq samples show relatively low voltage in both cases. The less defined 4.5 V platform accounts for approximately 20% of the initial charging capacity.

The capacity of all x = 0.17 samples increased by approximately 10 mAh g ⁻¹ between the first two C/20 discharges. As can be seen in Table III, the capacity of 17Hq, 17Lq and 17Mq increased by 31%, 73% and 91% respectively in the second round of C/20 discharge. All three samples exhibit approximately uniform voltage decay behavior and the average plateau voltage drops by approximately 0.4 V during cycling. However, this voltage decay was not seen in the C/20 discharge curves of these samples. The x = 0.17 sample also has a similar average discharge voltage over time. The main difference is that the average voltage of 17Mq increases in the first cycle, but it matches the voltage attenuation trend of 17Hq and 17Lq before the second cycle.

Referring to Figures 14A to 14D, regarding the charging profile of the x = 0.10 sample, the 10Hq charging profile is different from the 10Lq and 10Mq samples, which have similar profiles. Although all three samples have a sustained inflection point at 4.5 V, and the inflection point at 10Hq disappears and the inflection point for the 10Lq and 10Mq samples continues until cycle 54, only the 10Hq sample has a defined 4.5 V plateau. The inflection point of the 10Mq sample is the most obvious.

As can be seen in Table III, all x = 0.10 samples experienced an initial capacity increase of approximately 5 mAh g−1 during the first C/20 cycle, followed by the capacity of the 10Hq, 10Lq, and 10Mq samples during the second C/20 discharge cycle. Improvements of 300%, 60% and 67% respectively. Before the end of the first round of C/2 discharge, the capacity of all x = 0.10 samples exceeded or caught up with the initial C/20 capacity. During the two rounds of C/2 discharge, in the first and second rounds respectively, the visible capacity of 10Hq increased by 197% and 50%, the visible capacity of 10Lq increased by 25% and 16%, and the visible capacity of 10Mq increased by 36% and 20 %. The discharge plateau of the 10Lq and 10Mq samples starts at ∼3.0 V, while the plateau of the 10Hq sample starts at 3.2 V; the voltage behavior of 10Hq during cycling is different from that of 10Lq and 10Mq. The voltage behavior of all x = 0.10 samples is rate dependent, and the average discharge voltage of the C/20 discharge of all three samples increases during cycling. However, the C/2 discharge of the 10Lq and 10Mq samples showed signs of voltage decay, while the C/2 discharge of 10Hq did not.

In addition, the 10Lq and 10Mq samples have an inflection point at 2.2 V, which only exists on the C/20 discharge curve. These voltage behaviors of the x = 0.10 sample show that the average discharge voltage of the 10Lq and 10Mq samples is higher than that of 10Hq, but also shows a greater degree of voltage decay.

Regarding the rate capacity, as shown in Table III, the C/20:C/2 ratios of the 10Hq, 10Lq and 10Mq samples are 1.27, 1.60 and 1.67 respectively. It should be noted that the effective charge and discharge of each cycle also changes significantly from cycle to cycle, which makes the DC28/DC27 ratio of 10Hq actually a C/10:C/1 ratio.

The phase transition that changes during the test is shown in the voltage profile observed during cycling. The expected voltage plateau visible in the x = 0.25 sample indicates the expected classical phase transition.

Figures 15A to 15I are graphs showing normalized and offset XRD patterns of LRMO powders before and after cycling for samples 25Hq, 25Lq, 25Mq, 17Hq, 17Lq, 17Mq, 10Hq, 10Lq and 10Mq, respectively.

Referring to Figures 15A to 15I, the XRD patterns of all x = 0.25 samples after cycling have lost the 2θ = 22° superlattice peak, indicating that transition metal migration must have occurred to balance the structure. However, all other R-3m index peaks are still present, indicating that the overall structure is preserved. Similar results are seen in the x = 0.17 and 10Hq samples. This loss of transition metal order is associated with oxygen and lithium loss and therefore reduced capacity, whereas the increased capacity seen in Figures 12A to 14C confirms that this is not the case for these samples. Therefore, these data indicate that migration of these transition metals does not always result in capacity loss.

The 10Mq sample has a substantially different crystal structure after cycling testing, although both the 10Mq and 10Lq samples still have some visible peaks at 22°, further indicating that the electrochemical phase change system visible in Figures 14A to 14C is different from that in Figures 12A to 13C It can be seen from the cycle data that the phase transitions are different. The alternating phase transitions seen in 10Lq and 10Mq indicate that the synthesis limit of LRMO exists at 0.17 ＞ x ＞ 0.10 nickel content.

Figure 16 includes SEM micrographs at 50 k× of cathodes sprayed with 25Hq, 25Lq and 25Mq samples before and after cycling. Figure 17 includes SEM micrographs at 50 k× of cathodes sprayed with 17Hq, 17Lq and 17Mq samples before and after cycling. Figure 18 includes SEM micrographs at 5 k× of cathodes sprayed with 10Hq, 10Lq and 10Mq samples before and after cycling.

Referring to Figures 16 to 18, the morphology of the fabricated and cycled cathodes visible in Figures 16 and 17 is uniform across all x = 0.25 and x = 0.17 samples. The morphology of the x = 0.10 sample shown in Figure 18 is inconsistent. The 10Hq series is consistent with higher nickel content samples, while the 10Lq and 10Mq series are consistent with each other. All samples had consistent morphology before and after cycling; there was no evidence of changes in surface structure or particle morphology as a result of electrochemical cycling.

Both the nickel content and the quenching method affect the structure and electrochemical behavior of the LRMO cathode. In general, materials have higher capacities and more classic voltage behavior when synthesized with higher Ni contents and/or faster quenching rates, although the results sometimes vary slightly.

XRD patterns of LRMO powders show structural dependence on both nickel content and quenching method. Slight crystallographic changes are expected in samples with various nickel contents and are observed between x = 0.25 and x = 0.17 and 10Hq samples. The XRD patterns of 10Lq and 10Mq have a large number of secondary peaks, but the XRD pattern of 10Hq does not. The secondary peaks visible in the patterns of 10Lq and 10Mq are consistent with the secondary peaks visible in the XRD patterns of the 25Mq and 17Mq samples. These examples demonstrate the importance of quenching rate in determining structure, phase content and phase purity.

The secondary lamellar phase found in many samples may be the result of local relatively nickel-rich heterogeneity with correspondingly large lattice parameters. Except for 25Hq and 25Lq, there is (110) peak splitting in the XRD patterns of all samples, which confirms that slower quenching leads to nickel heterogeneity. The XRD patterns of the 25Mq and 17Mq samples have additional secondary peaks at (101), (104), and (107), which are visible in the 10Lq and 10Mq samples. Although it must be noted that the (104) sub-peaks of 25Mq and 10Lq may be caused by contaminants. These additional peaks, although variable, still appear in all metal-quenched samples, confirming that the structure depends on both the nickel content and the degree of quenching. These data support the concept that slower quenching methods result in segregated nickel-rich phase regions and the formation of contaminants in the material, thereby determining the local ordering of nickel in these samples regardless of Ni content. Figure 24 shows a schematic diagram of the proposed structure for this secondary layered phase.

Since Ni ²⁺ ions have a larger ionic radius than Mn ions, it is believed that the less Ni present, the less local lattice expansion will occur. Samples with higher nickel content should have a higher degree of long-range ordering in the distribution of the nickel ions, and more favorable ordering resulting in smaller lattice parameters. Fast quenching of these samples preserves long-range order and smaller lattice parameters, while slower quenching should allow the nucleation of contaminants and the evolution of nickel heterogeneity, both of which distort the average lattice parameters. The intersection point visible in Figure 26B for lattice parameter "a" is at x = 0.11, further indicating that there is a synthesis limit of 0.17 > x > 0.10.

The electrochemical behavior of the sample is affected by both the nickel content and the quenching method. The first charge behavior of a material is indicative of purity and capacity, as high performance materials are known to display a single strong plateau consistent with phase transitions via nickel-catalyzed oxygen and lithium losses.

Figures 19A to 19C are graphs showing smoothed spline fits of dQ/dV and V data for the first charge cycle for x = 0.25, x = 0.17, and x = 0.10 samples.

Referring to Figures 19A to 19C, the 4.5 V peak visible on the dQ/dV plot confirms that all samples have an initial 4.5 V plateau to some extent. However, Figures 12A to 14C show that only some of these samples have an inflection point at 4.5 V upon subsequent charging. This confirms that all samples initially undergo similar phase transitions, although the persistence of the inflection point in some samples suggests that the reaction is not always able to complete during the initial charge. Samples with secondary peaks in the spectrum are the same as those with inflection points in subsequent cycles, and therefore can be correlated. This is further supported by how higher nickel content will drive the secondary lamellar phase peak to the left of the main peak. Although some samples (such as 25Mq and 10Lq) show signs of rock salt contamination, this contamination does not exclude the possibility of some other phase changes. Regardless, these transformations occurred over many cycles and gradually decayed, indicating that ultimately the sample was completely and irreversibly transformed.

The presence of inflection points on the non-water quenched samples, except for some at 10Hq, provides further evidence that these inflection points are related to phase heterogeneity. The 10Hq sample starts at this inflection point, but before cycle 54, its charge profile is closer to the x = 0.17 sample than to its initially similar x = 0.10 sample. Therefore, these data are consistent with the evolution of nickel heterogeneity extending the 4.5 V phase transition.

Figures 20A-20C are graphs showing smoothing spline fits of dQ/dV versus V data for the second charge cycle for x = 0.25, x = 0.17, and x = 0.10 samples. Figures 21A to 21C are graphs showing the first C/2 discharge and the last C/2 discharge of the 25Hq, 25Lq and 25Mq samples, and Figure 21D is a graph showing the average discharge voltage of each cycle of the 25Hq, 25Lq and 25Mq samples during the cycling process. Figure. Figures 22A to 22C are graphs showing the first C/2 discharge and the last C/2 discharge of the 17Hq, 17Lq and 17Mq samples, and Figure 22D is a graph showing the average discharge voltage of each cycle of the 17Hq, 17Lq and 17Mq samples during the cycling process. Figure. Figures 23A to 23C are graphs showing the first C/2 discharge and the last C/2 discharge of the 10Hq, 10Lq and 10Mq samples, and Figure 23D is a graph showing the average discharge voltage of each cycle of the 10Hq, 10Lq and 10Mq samples during the cycling process. Figure.

The discharge profile of the sample also shows that the cyclic behavior over time is affected by the nickel composition and quenching method. Referring to Figures 20A to 20C, the peak initial average voltage of the water-quenched sample is lower than that of the liquid nitrogen and metal-quenched samples, indicating that nickel heterogeneity affects the voltage. Except for 25Mq, the average discharge voltage of the water-quenched sample also tends to be lower than other samples with the same composition. The dQ/dV plots of 17Lq and 17Mq and Figures 21A to 23D show how the discharge profile evolves different behaviors within the cycle. Although the voltage of the x = 0.17 sample is the most homogeneous in terms of voltage behavior, a greater degree of voltage attenuation is also seen. The exceptions to this are the 25Mq sample, which sees voltage decay during cycling; and the x = 0.10 sample, which sees a voltage increase equal to C/20 discharge and a voltage decay equal to C/2 discharge. It is also important to note that the average voltage degradation experienced by most samples has been shown to be due to the evolution of greater capacity at those voltages rather than the degradation of those samples. The significant differences in discharge behavior seen in these samples indicate that differences in quenching rates also occur in different electrochemical reactions.

When compared with the voltage attenuation of the x = 0.17 sample, the voltage attenuation of 25Hq and 25Lq is slighter, and their associated voltage platforms are also at different voltages. The slighter voltage attenuation of 25Hq and 25Lq is basically consistent with the phase transition of the spinel-like phase during cycling, which is associated with the 3 V plateau. The more severe voltage attenuation system of these x = 0.17 samples is also basically consistent with the phase transition of the spinel-like phase. In both cases, but specifically in the case of the x = 0.17 sample, these voltage platforms are close to the average voltage of Ni ^2+/3+/4+ redox in a manganese-rich environment, indicating that these platforms are Driven by nickel redox and therefore nickel distribution. This voltage loss and nickel redistribution are basically consistent with the evolution of the spinel-like phase, and the main inconsistency is the increase in capacity. The evolution of the spinel-like phase has been associated with both the initial capacity increase and the loss, which seems to Commonly associated with significant structural deterioration. Therefore, the voltage attenuation of the structurally solid 25Hq, 25Lq and x = 0.17 samples is probably not entirely due to the evolution of the spinel-like phase.

The evolution of the spinel-like phase also does not explain the behavioral differences between discharge rates, specifically for the x = 0.10 sample. The C/20 discharges of these x = 0.10 samples start at a similar voltage to the decaying samples and increase in voltage during cycling; the C/2 discharges of the x = 0.10 samples experience a certain degree of voltage decay. Although the lower initial potential of these samples is likely related to their larger manganese concentration and subsequent lower nickel redox potential, the inconsistent voltage behavior cannot be fully explained by the formation of a spinel-like phase, especially when considering its When the capacity is rapidly increased. In contrast, the lower manganese concentration, capacity loss, and faster voltage decay of 25 Mq indicate the formation of a spinel-like phase. These factors (actually the way the discharge voltage plateau starts at 3 V) are consistent with the voltage decay mechanism of spinel-like phase evolution. Phase impurities that evolve during slow quenching may make the evolution of 25Mq into a spinel-like phase system more likely. The voltage platform of 25Mq falls within the range of Mn ^3+/4+ redox couple, and manganese and nickel may form a mixed redox couple, which can also explain the voltage attenuation. The discharge platforms of 10Lq and 10Mq are similar to those of 25Mq starting at 3 V, which indicates that these samples can also undergo a certain degree of transformation to a spinel-like phase. The XRD of all samples (except 10Mq) has peaks indicating the R-3m layered structure, further indicating that the evolution of the spinel-like phase is not completely responsible for the voltage attenuation or capacity changes.

Figure 24 is a schematic diagram showing the manner in which phase impurity inclusions in a 25Mq sample with an R-3m structure and a lattice parameter a' > a give rise to secondary peaks as visible to the left of the 25Mqs (104) peak. As shown in Figure 24, the redox of nickel driving the evolution of these platforms would indicate a homogenization of nickel content over time.

In addition to 25Mq, the electrochemical cycle data of the LRMO cathode shows that the capacity continues to increase. While the x = 0.25 sample saw a slight increase in capacity, the x = 0.17 sample saw a more significant increase, and the x = 0.10 sample saw an even greater increase. Therefore, the increase in the percentage of specific capacity over the cycle shows an inverse relationship with the nickel content regardless of the quenching method. The largest increase in capacity is seen in the 10Hq sample and then the 10Mq and 10Lq samples. Since impurities are related to nickel heterogeneity, this relationship suggests that the capacity increase is driven at least in part by homogenizing the nickel content through "electrochemical annealing" during cycling.

Comparison of cathode materials after cycling with original cathode materials. XRD shows that the behavior of all samples is very similar, except for 10Lq and 10Mq, where the transition metal superlattice peak disappears after cycling. 10Lq has some retained superlattice peaks after cycling, and several new peaks can be seen in the 10Mq sample, marking significant differences between the two samples. This difference further shows the importance of quenching rate, as there appears to be a synthetic lower limit for LRMO at slower quenching conditions, where 0.17 > x > 0.10. However, the behavior of the 10Hq sample is different and shows that more rapid quenching of this sample can lead to the stability and long-term performance associated with higher Ni content samples.

Electrochemical testing of these materials showed that the rapidly quenched material had excellent capacity and capacity retention and was the only variant that showed an increase in capacity during cycling. After 50 full charge/discharge cycles, the material produced a specific capacity of nearly 230 mAh/g at a C/2 rate, which is far superior to materials cooled in other ways.

It has been discovered that the use of extremely rapid cooling of such materials by immersion in water during synthesis results in materials with excellent and differentiated crystal structures and never-before-reported electrochemical behavior. Specifically, we found that this water-quenched material: (a) showed a significant increase in capacity over 50 cycles, (b) did not show the commonly reported voltage decay (in which the average discharge voltage of the battery decreases significantly with use), (c) Having a specific capacity exceeding 250 mAh/g after 25 cycles at the C/2 rate and after 4 cycles at the C/2 rate, and (d) Having a specific capacity exceeding 250 mAh/g after 50 cycles at the C/2 rate A specific capacity of 230 mAh/g (eg, 231 to 240 mAg/g) and an average voltage loss during discharge of less than 10% (eg, for example, as shown in Figure 21D).

Figure 26A is a graph showing the index normalized and offset XRD pattern of the original LRMO active material powder with the following formula: Li[Ni _x Li( _1/3–2x/3 )Mn _(2/3−x/3) ] O ₂ , with nickel content, x = 0.25. This formula can also be written as Li _z (Mn _y Ni _1-y ) _2-z O ₂ , where z = 1.16, and y = 0.7, and their equivalents using Hq, Lq, and Mq (i.e., water, liquid nitrogen, respectively and metal quenching). Figure 26B includes a top graph showing the trend between the lattice parameter "a" and the nickel content of the sample, and a bottom graph showing the trend between the lattice parameter "c" and the nickel content of the sample, via single phase Ritter. Wald fit is obtained.

As shown in Figure 26A, X-ray diffraction evaluation of the materials revealed that the materials possess related hexagonal (e.g., rhombohedral) phases of LiNiO with space group (R-3m), and _LiNiO2 with space group (C2/c) Li ₂ NiO ₃ related monoclinic phase. This indicates that all samples have the expected layered structure. It should be noted that the monoclinic phase diffraction peak is the most well-defined among the samples produced by the Hq method, indicating that this method produces a more well-defined crystal structure.

There is also a superlattice peak around 22°, which is indicative of this family of compounds. The XRD patterns of the 10Lq and 10Mq samples also have significant peaks to the left of the (101), (104), (015), (107) and (108) peaks, indicating that the coarse particles have a similar structure and a larger lattice than the bulk phase. Parameters of phase impurities. The lack of other peaks suggests that in this case all impurities are isomorphic to the bulk of the material. The XRD pattern of the 10Hq sample shows only small additional (107), (108) and (110) peaks. Although not visible in these XRD patterns, the 17Mq and 25Mq samples may also have indications of phase impurities; there are small secondary peaks to the left of the (104) and (107) peaks respectively. In addition, the (108) peak of the 25Mq sample has a shoulder on its left side. Closer examination of the (104) maximum indicates differences between this second set of peaks and the secondary peaks of the 25Hq and 10Mq samples, indicating that the isomorphic impurity is likely to be a nickel-rich layered structure, whereas the peaks of the 10Lq and 25Mq samples It shows that the isomorphic impurities are probably ordered rock salt. These data indicate that there should be two sources for these peak sets: one is another layered phase and the other is the contaminant rock salt. In this article, "secondary lamellar phase" will refer to localized regions with compositional differences and corresponding structural deformations, specifically regions with higher nickel content and resulting larger lattice parameters, while "contaminants" will be Refers to the rock salt phase.

The lattice parameters of the powders in Figure 26A were obtained using Rietwald refinement based on single phases. All samples had weighted R values less than 6, and the lattice parameters of the known compositions fell within the limits seen in the reference. (See S1 available online at stacks.iop.org/JES/167/160518/mmedia and incorporated by reference in full). The refinement system is limited to single phases. Figure 26B shows that the lattice parameter "a" decreases with decreasing nickel content in these samples regardless of the quenching technique. Although the liquid nitrogen quenched x = 0.10, 0.17 and 0.25 samples deviate from this trend, the same trend is widely suggested for the lattice parameter "c". Except for the 10Lq and 17Lq samples, the quenching method at x ≥ 0.10 shows that the slower quenching method can lead to a larger lattice parameter "a", with the same general trend for the lattice parameter "c".

In one embodiment, a method of forming an active material for a positive electrode of a lithium-ion battery includes quenching a powder of the active material in water. In one embodiment, the method further includes firing the active material powder prior to the quenching. The active material can be fired at a temperature of at least 800°C. The water can be at room temperature prior to the quenching, and the powder of active material can be quenched at a rate of at least 1750°C/second.

In one embodiment, the active material includes layered lithium-rich nickel manganese oxide. Excess Li, Ni and Mn atoms may be distributed homogeneously and uniformly throughout the transition metal lattice sites such that the ratio of Ni, Mn and Li atoms is between No material with a difference greater than 3% has a crystalline volume greater than 3 x 3 x 3 nm. Particles of the powder of the active material may be in the shape of agglomerates having an average size in the range of about 0.1 µm to about 20 µm, and the agglomerates of the powder of the active material may be in the shape of agglomerates having an average size in the range of about 25 nm to about 500 µm. Composition of microcrystals with an average size in the range of nm. The powder of the active material may comprise a composite of hexagonal and monoclinic phases after quenching, and is a combination of LiMO ₂ R-3m and Li ₂ MnO ₃ C2/m phases, where M is at least one of Ni or Mn. The powder of the active material may comprise a solid solution having a crystal structure having predominantly or entirely C2/m symmetry. The powder of the active material may comprise a solid solution having a crystal structure having predominantly or entirely R-3m symmetry.

In one embodiment, the active material is represented by the following formula: Li[Ni _x Li( _1/3–2x/3 )Mn _(2/3−x/3) ]O ₂ , where 0 < x < 0.5. In one embodiment, the active material is substantially free of cobalt; and the active material is represented by the following formula: Li[Ni _x Li( _1/3–2x/3 )Mn _{(2/3−x/3 )} ]O ₂ , where 0.19 ＜ x ＜ 0.26, or expressed by the following formula: Li[M _x Li( _1/3–2x/3 )Mn _(2/3−x/3) ]O ₂ , where 0.19 ＜ x < 0.26, and wherein M includes Ni and at least one of Ti, Fe, Al or Cr.

In one embodiment, the water contains additives solvated therein. The water may contain from 0.01 mole per liter to 1.0 mole per liter of this additive. In one embodiment, the additive includes an acid that may be selected from sulfuric acid, citric acid, acetic acid, phosphoric acid, hydrochloric acid, ammonium phosphate, or combinations thereof. In another embodiment, the additive includes a carbohydrate, which may be selected from fructose, galactose glucose, lactose, maltose, sucrose, or combinations thereof.

In one embodiment, the active material is placed within the positive electrode of a lithium-ion battery cell further including a negative electrode and an electrolyte. Before electrochemical cycling of the battery, the active material includes hexagonal and monoclinic phases; and after the electrochemical cycling, the active material powder does not include the monoclinic phase.

In one embodiment, the specific discharge capacity of the battery cell increases by at least 10% within 50 electrochemical cycles at a charge rate of C/20 and a discharge rate of C/2 at room temperature in a voltage range of 2V to 4.8V. ; and the battery unit has a specific capacity of at least 230 mAh/g after 50 electrochemical cycles at a discharge rate of C/2.

In one embodiment, a lithium ion battery cell includes: a negative electrode; an electrolyte; and a cathode including a layered lithium-rich nickel manganese oxide active material, wherein the battery cell has a specific discharge capacity at a charge rate of C/20 and C/ The battery cell has a specific capacity of at least 230 mAh/g after 50 electrochemical cycles at a discharge rate of C/2.

In one embodiment, the specific discharge capacity of the battery cell is within a voltage range of 2V to 4.8V at room temperature during two electrochemical cycles at a charge rate of C/20 and a discharge rate of C/20, followed by Twenty-five electrochemical cycles at a charge rate of C/20 and a discharge rate of C/2, followed by two additional electrochemical cycles at a charge rate of C/20 and a discharge rate of C/20, and then at a discharge rate of C/20 Twenty-five additional electrochemical cycles at a charge rate of C/2 and a discharge rate of C/2 increase by at least 10%. In one embodiment, the average discharge voltage of the battery cell decreases by no more than 10% within 50 electrochemical cycles at a discharge rate of C/2.

In one embodiment, the active material is represented by the following formula: Li[M _x Li( _1/3–2x/3 )Mn _(2/3−x/3) ]O ₂ , where 0 < x < 0.5, And M includes Ni or a combination of Ni and at least one of Ni, Al, Fe or Cr. In one embodiment, the active material is substantially free of cobalt; and the active material is represented by: Li[M _x Li( _1/3–2x/3 )Mn _(2/3−x/3) ]O ₂ , where 0.19 < x < 0.26 and M includes Ni. In one embodiment, the active material is represented by the formula y(LiMO ₂ )∙(1-y)LiMnO ₃ , where y ranges from 0.8 to 1, and M includes at least Ni and Mn.

In one embodiment, the particles of the powder of the active material are in the shape of agglomerates having an average size in the range of about 0.1 µm to about 10 µm, and the agglomerates of the powder of the active material are formed by having The particles of the active material powder have at least one of a spinel surface layer, a carbon coating, or passivated oxygen bonds on the surface.

In one embodiment, the excess Li, Ni, and Mn atoms are homogeneously and uniformly distributed throughout the transition metal lattice sites such that compared to the average ratio of Ni, Mn, and Li atoms in the bulk material, the Ni, Mn Materials with a greater than 3% difference in the ratio of Li and Li atoms do not have a crystalline volume greater than 3 x 3 x 3 nm.

The foregoing description of the disclosed aspects of the invention is provided to enable those skilled in the art to make or use the invention. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the invention. Thus, the present invention is not intended to be limited to the aspects shown but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

100: Rapid quenching system 110:Tube furnace 120:Quenching bath

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate example embodiments of the invention and, together with the general description given above, and the detailed description given below, serve to explain features of the invention.

Figure 1 is a photograph of a rapid quenching system according to various embodiments of the present invention.

Figure 2 includes four consecutive video capture time-lapse images taken at 30 frames per second showing the rapid quenching process in accordance with various embodiments of the present invention.

_{Figures 3} and 4 _show , _respectively , _the Diagram of ray diffraction (XRD) pattern.

Figure 5 shows a Li _x (Mn _y Ni _1-y ) _2-x O ₂ material (where x = 1.16, and y = 0.7) X-ray diffraction pattern.

Figure 6 is a diagram illustrating Li _x (Mn _y Ni _1-y ) _2-x O ₂ material (where x = 1.16 and y = 0.7) using microwave heating and ultra-rapid quenching according to various embodiments of the present invention. Diagram of an X-ray diffraction pattern.

Figure 7A is a tunneling electron microscopy (TEM) atomic image micrograph of a prior art LRMO material that was not subjected to rapid quenching prior to electrochemical cycling of the material.

Figure 7B is a TEM HAADF atomic image micrograph of an LRMO material that was subjected to rapid quenching prior to electrochemical cycling of the material, in accordance with various embodiments of the present invention.

Figure 8A is a graph showing cell potential versus specific capacity, and Figure 8B is Li _x (Mn _y Ni _{1-y )} without either microwave treatment or rapid quenching (in this case relatively slow cooling on a metal disk) Plot of specific capacity versus cycle for a comparative example of _2-x O ₂ material where x = 1.16 and y = 0.7.

Figure 9A is a graph showing battery potential versus specific capacity during a running-in cycle, Figure 9B is a graph showing battery potential versus specific capacity over time, Figure 9C is a graph showing specific capacity versus cycle at C/20 rate, and Figure 9D is a graph showing discharge specific capacity versus cycle number for a C/20 reference cycle at a C/5 rate for an exemplary cell including an LRMO active material according to various embodiments of the invention.

Figure 10A shows the cell potential and specific capacity of a comparative cell including Li _x (Mn _y Ni _1-y ) _2-x O ₂ active material without microwave treatment or rapid quenching (where x = 1.16 and y = 0.7). , Figure 10B is a graph showing the specific capacity and cycle of the battery of Figure 10A.

Figure 10C is a graph showing cell potential versus specific capacity for an exemplary cell including a rapidly water-quenched _Lix ( _{MnyNi1 -y} ) _{2-xO2 active} material where x = 1.16 and y = 0.7 . Figure 10D is a graph showing specific capacity versus cycle for the battery of Figure 10C.

Figure 11A shows the cell potential and specific capacity of an exemplary cell including microwave decomposed and rapidly quenched Li _x (Mn _y Ni _1-y ) _2-x O ₂ active material where x = 1.16 and y = 0.7 , and FIG. 11B are graphs showing specific discharge capacity versus cycle at C/20 and C/2 rates for the battery of FIG. 11A , in accordance with various embodiments of the present invention.

Figure 12A shows _a lithium-rich nickel manganese oxide material having the _formula Li _{[ Ni} Graphs of the specific discharge capacity of the samples during cycling, and Figures 12B to 12D show the full charge and discharge curves of coin cells including the 25Hq, 25Lq and 25Mq samples respectively.

Figure 13A is a graph showing the specific discharge capacity of the x = 0.17 sample during cycling, and Figures 13B to 13D show the full charge and discharge curves of coin-type batteries including the 17Hq, 17Lq and 17Mq samples respectively.

Figure 14A is a graph showing the specific discharge capacity of the x = 0.10 sample during cycling, and Figures 14B to 14D show the full charge and discharge curves of coin cells including 10Hq, 10Lq and 10Mq samples respectively.

Figures 15A to 15I are diagrams showing the normalized and offset XRD patterns of LLRNMO powder before and after cycling for 25Hq, 25Lq, 25Mq, 17Hq, 17Lq, 17Mq, 10Hq, 10Lq and 10Mq samples respectively.

Figure 16 includes SEM micrographs at 50 k× of cathodes sprayed with 25Hq, 25Lq and 25Mq samples before and after cycling.

Figure 17 includes SEM micrographs at 50 k× of cathodes sprayed with 17Hq, 17Lq and 17Mq samples before and after cycling.

Figure 18 includes SEM micrographs at 5 k× of cathodes sprayed with 10Hq, 10Lq and 10Mq samples before and after cycling.

Figures 19A to 19C are graphs showing smoothed spline fits of dQ/dV and V data for the first charge cycle for x = 0.25, x = 0.17, and x = 0.10 samples.

Figures 20A to 20C are graphs showing smoothed spline fits of dQ/dV and V data for the second charge cycle for x = 0.25, x = 0.17, and x = 0.10 samples.

Figures 21A to 21C are graphs showing the first C/2 discharge and the last C/2 discharge of the 25Hq, 25Lq and 25Mq samples, and Figure 21D is a graph showing the average discharge voltage of each cycle of the 25Hq, 25Lq and 25Mq samples during the cycling process. picture.

Figures 22A to 22C are graphs showing the first C/2 discharge and the last C/2 discharge of the 17Hq, 17Lq and 17Mq samples, and Figure 22D is a graph showing the average discharge voltage of each cycle of the 17Hq, 17Lq and 17Mq samples during the cycling process. picture.

Figures 23A to 23C are graphs showing the first C/2 discharge and the last C/2 discharge of the 10Hq, 10Lq and 10Mq samples, and Figure 23D is a graph showing the average discharge voltage of each cycle of the 10Hq, 10Lq and 10Mq samples during the cycling process. picture.

Figure 24 is a schematic diagram showing the manner in which phase impurity inclusions in a 25Mq sample with an R-3m structure and a lattice parameter a' > a give rise to secondary peaks as visible to the left of the 25Mqs (104) peak.

Figures 25A-25B are SEM micrographs of agglomerates and Figures 25C-25D are higher magnification SEM micrographs of microcrystals (eg, crystal grains) in the agglomerates.

Figure 26A is a plot of intensity (in arbitrary units) versus angle 2θ (in degrees) showing indexed normalized and offset XRD patterns of pristine layered lithium-rich nickel manganese oxide (LLRNMO) powder. Figure 26B includes a top graph showing the trend between the lattice parameter "a" and the nickel content of the sample, and a bottom graph showing the trend between the lattice parameter "c" and the nickel content of the sample, via single phase Ritter. Obtained by Rietveld fitting.

Claims (27)

A method comprising: sintering a lithium-rich metal oxide (LRMO) material at a sintering temperature to form a sintered LRMO material; and quenching the sintered LRMO material from the sintering temperature to room temperature in less than 500 milliseconds to form a sintered LRMO material. The quenched LRMO material is represented by the following chemical formula: Li _x (Mn _y Ni _1-y ) _2-x O ₂ , where x is greater than 1.05 and less than 1.25, and y is in the range of 0.95 to 0.1. Such as the method of request item 1, where: The sintering temperature is at least 800°C; and Quenching the sintered LRMO material from the sintering temperature to the room temperature includes quenching the sintered LRMO material from the sintering temperature to the room temperature in 200 milliseconds or less. Such as the method of request item 1, where: The sintering temperature ranges from 900°C to 950°C; and Quenching the sintered LRMO material from the sintering temperature to the room temperature includes quenching the sintered LRMO material from the sintering temperature to the room temperature within 100 to 200 milliseconds. Such as the method of request item 1, where: The sintering includes sintering the LRMO material in a furnace; and Quenching the sintered LRMO material includes quenching the LRMO material in a quench bath. Such as the method of request item 4, wherein: The time between removing the sintered LRMO material from the furnace and quenching the sintered LRMO material in the quench bath to room temperature of 25°C is 200 milliseconds or less; and The quenching bath contains an aqueous bath. The method of claim 4, wherein the quenching bath includes an oil bath, an alcohol bath, or a water bath containing additives, the additives including acids, carbohydrates, alcohols, or combinations thereof. The method of claim 1 further includes: Forming a mixture of water and metal-organic precursors of lithium, nickel and manganese; heating the mixture to form a gel; and Microwave radiation is used to thermally decompose the gel to form the LRMO material. Such as the method of request item 7, wherein: The gel contains a 0.01 to 0.20 molar fraction excess of a metal-organic precursor of lithium; and The LRMO material includes inorganic LRMO material containing lithium, nickel, manganese and oxygen. The method of claim 1, further comprising drying the quenched LRMO material to form an LRMO active material, and providing the LRMO active material to a cathode electrode of a lithium ion battery containing an anode electrode and an electrolyte. The method of claim 9, wherein the LRMO active material exhibits at least one of the following: The crystalline particles of the LRMO active material exhibit a uniform distribution of Mn and Ni atoms throughout the crystalline particles such that there are no Ni-rich or Mn-rich regions when imaged by HAADF EDS; Compared with non-quenched LRMO materials with the same composition, the ratio of (006)+(102):(101) x-ray diffraction peaks increases by at least 6%; The ratio of x-ray diffraction peaks between (003) and (104) is greater than 2; Deliver at least 165 mAh/g specific capacity when the lithium-ion battery is first discharged; After 200 charge/discharge cycles of the lithium-ion battery, the average discharge voltage loss at the C/20 rate is less than 10%; or The lithium-ion battery loses less than 10% of its capacity within 200 C/5 charge/discharge cycles. A method comprising: thermally decomposing a precursor material using microwave radiation to form a thermally decomposed lithium-rich metal oxide (LRMO) material; sintering the thermally decomposed LRMO material to form a sintered LRMO material; and quenching the sintered LRMO material to form a sintered LRMO material. The quenched LRMO material is represented by the following chemical formula: Li _x (Mn _y Ni _1-y ) _2-x O ₂ , where x is greater than 1.05 and less than 1.25, and y is in the range of 0.95 to 0.1. Such as the method of claim 11, wherein the precursor materials include metal organic precursors of Li, Mn and Ni, selected from at least one of the following: acetate, carbonate, nitrate, sulfuric acid of Li, Mn and Ni salt or hydroxide. The method of claim 12 further includes: Forming a mixture of water and metal-organic precursors of lithium, nickel and manganese; and Heat the mixture to form a gel, wherein the step of thermally decomposing the precursor materials includes using the microwave radiation to heat the gel, and wherein the gel contains a 0.01 to 0.20 molar fraction excess of a metal-organic precursor of lithium. The method of claim 11, wherein the precursor materials comprise precursors of coprecipitated hydroxides of Mn and Ni mixed with lithium carbonate. The method of claim 11, wherein the quenching includes quenching the sintered LRMO material from the sintering temperature to room temperature in less than 500 milliseconds to form a quenched LRMO material. The method of claim 11, further comprising drying the quenched LRMO material to form an LRMO active material, and providing the LRMO active material to a cathode electrode of a lithium ion battery containing an anode electrode and an electrolyte. A cathode electrode active material represented by the following chemical formula, Li _x (Mn _y Ni _1-y ) _2-x O ₂ , wherein x is greater than 1.05 and less than 1.25, and y is in the range of 0.95 to 0.1, wherein the active material Comprised of layered hexagonal and monoclinic phases, and wherein the active material exhibits at least one of the following: (006)+(102):(101) x-ray diffraction peak intensity ratio greater than 0.32, when included in a lithium-ion battery Medium, delivers at least 165 mAh/g specific capacity at the C/20 rate when first discharged; when included in this lithium-ion battery, the average discharge at the C/20 rate after 100 charge/discharge cycles The voltage loss is less than 10%; or when included in the lithium-ion battery, the capacity decay is less than 10% within 100 C/5 charge/discharge cycles. The active material of claim 17, wherein the particles of the active material comprise a carbon coating or an acid-modified surface. The active material of claim 17, wherein the active material exhibits an x-ray diffraction peak intensity ratio of (106)+(102):(101) greater than 0.32. The active material of claim 19, wherein the active material exhibits a ratio of (003) to (104) x-ray diffraction peaks greater than 2. The active material of claim 17, wherein the crystalline particles of the active material exhibit a uniform distribution of Mn and Ni atoms throughout the crystalline particles such that there are no Ni-rich or Mn-rich regions when imaged by HAADF EDS. A lithium-ion battery containing: A cathode electrode comprising an active material as claimed in claim 17; anode electrode; and Electrolytes. The battery of claim 22, wherein when the lithium-ion battery is first discharged, the active material delivers at least 165 mAh/g specific capacity at a C/20 rate. The battery of claim 22, wherein the lithium-ion battery has an average discharge voltage loss of less than 10% at a C/20 rate after 100 charge/discharge cycles. Such as the battery of claim 22, wherein the active material shows less than 10% capacity degradation within 100 C/5 charge/discharge cycles. Such as the battery of claim 22, wherein: The average discharge voltage of the lithium-ion battery does not decrease by more than 5% within 50 C/20 (charge) - C/2 (discharge) charge/discharge cycles; or The discharge capacity of the lithium-ion battery is greater than 80% of its initial capacity after 800 or more C/20-C/2 charge/discharge cycles. A method of operating a lithium-ion battery as claimed in claim 22, comprising performing a plurality of charge/discharge cycles, wherein: The active material delivers a specific capacity of 165 mAh/g at a C/20 rate when the lithium-ion battery is first discharged; The lithium-ion battery has an average discharge voltage loss of less than 10% at the C/20 rate after 100 charge/discharge cycles; or The active material shows less than 10% capacity degradation within 100 C/5 charge/discharge cycles.