TWI662736B - Method for preparing ruthenium-based electrode material, ruthenium-based electrode material, and lithium ion battery including the same - Google Patents

Abstract

The present invention provides a ruthenium-based electrode material and a preparation method thereof. The preparation method comprises the steps of: grinding the ruthenium raw material by high-energy mechanical grinding to obtain a one-micron ruthenium condensate; further mixing the micro-sized ruthenium condensate with a modifier to obtain a mixture, and grinding the mixture by wet grinding a base electrode material; wherein the modifier comprises ethanol, glucose, sucrose, fructose, starch, citric acid, glucosamine, L-alanine, oleic acid, oleylamine, cellulose acetate, carboxymethyl Cellulose, α-D-cellobiose octaacetate, heptylboronic acid, 1,4-dimethoxy-3-methylnaphthalene-2-boronic acid, 2,4,6-trifluorobenzeneboronic acid, half Cystine, acetylcysteine, dithiothreitol, ethylphosphonic acid, or a combination thereof; the ruthenium-based electrode material comprises a ruthenium aggregate comprising a plurality of surface-cold-necked nano-ruthenium a particle; wherein the nanoparticle particles have a primary particle diameter of less than 0.1 μm; the ruthenium aggregate median particle diameter is equal to or greater than 0.15 μm and equal to or less than 0.5 μm; and the ruthenium aggregate has a specific surface area equal to or greater than 20 m ² /g and equal to or less than 50 m ² /g. Further, a negative electrode including the foregoing ruthenium-based electrode material and a lithium ion battery including the foregoing negative electrode are also provided.

Description

Method for preparing ruthenium-based electrode material, ruthenium-based electrode material, and lithium ion battery including the same

The present invention relates to a ruthenium-based electrode material, and more particularly to a ruthenium-based electrode material for a negative electrode of a lithium ion battery, and the present invention also relates to a method for manufacturing the ruthenium-based electrode material, and the present invention also relates to a method A lithium battery comprising the ruthenium based electrode material.

With the rapid increase in demand for mobile electronic devices, electric vehicles (EVs), hybrid electric vehicles (HEVs), grid energy storage systems, etc., high power density and long cycle life Rechargeable lithium-ion batteries (LiBs) have attracted much attention. However, the current graphite anode materials used in lithium ion batteries cannot meet the production capacity requirements of the new generation of lithium ion batteries due to the limited theoretical specific capacity and the poor rate capability. Therefore, the theoretical value of high capacitance, the low discharge voltage, and the abundant enthalpy become the potential negative electrode materials. However, the ruthenium-based anode material has mechanical failure such as anode breakage due to volume change of more than 400% in the process of lithiation/delithiation, high irreversible capacity loss, and inability to maintain charge and discharge cycle characteristics, etc. problem.

In order to solve the above problem, in the related research, Japanese Patent Publication No. 2000-243396 discloses a composite powder comprising SiO-graphite. Although the cycle characteristics are improved, the production process needs to be subjected to high temperature treatment, which increases energy consumption and complicated process, and the battery charging capacity and discharge capacity made of the composite powder are still not as pure as those provided by the pure powder. Discharge capacity.

In addition, as mentioned in CK Chan et al., "High-performance lithium battery anodes using silicon nanowires", it is mentioned that the use of the nanowires has a higher stress without pulverization. Therefore, it can provide good electrical conductivity and can obtain good cycle characteristics; however, due to the complicated structure and process of the nanowire line synthesis, the quality control is difficult, and it is difficult to mass-produce and hinder the possibility of commercial development.

In view of the technical defects of the above-mentioned ruthenium-based electrode materials, the purpose of the present invention is to provide a ruthenium-based electrode material which has good electrical conductivity, cycle characteristics and capacitance retention.

Another object of the present invention is to provide a ruthenium-based electrode material, which has the advantages of lower manufacturing cost, and can solve the problem that the use of glutinous rice powder, glutinous rice wire and the like requires complicated processes, resulting in an increase in manufacturing cost, and further With the development potential of commercial products.

Another object of the present invention is to provide a ruthenium-based electrode material, which can not only solve the problem that the rhodium nano-powder and the ruthenium nanowire have poor rheological properties in the preparation of the electrode slurry, resulting in difficulty in handling, and can also solve the problem of using glutinous rice noodles. The problem that the density of the material such as the nanowire and the nanowire is low during electrode formation.

In order to achieve the foregoing object, the present invention provides a method for preparing a ruthenium-based electrode material, comprising the steps of: grinding a ruthenium raw material by high-energy mechanical grinding to obtain a one-micron ruthenium condensate; and mixing the micron-sized ruthenium condensate with a a modifier, a mixture is obtained, and the mixture is ground by a wet milling method to obtain a ruthenium-based electrode material; wherein the modifier comprises ethanol, glucose, sucrose, fructose, starch, citric acid, glucosamine, L- Alanine, oleic acid, oleylamine, cellulose acetate, carboxymethylcellulose, α-D-cellobiose octaacetate, heptylboronic acid, 1,4-dimethoxy-3-methylnaphthalene- 2-boric acid, 2,4,6-trifluorobenzeneboronic acid, cysteine, acetylcysteine, dithiothreitol, ethylphosphonic acid, or a combination thereof; the ruthenium-based electrode material includes a ruthenium aggregate a body comprising a plurality of surface-cold-controlled nano-particles; wherein the nano-particles have a primary particle size of less than 0.1 micrometer; and the median particle size of the cerium aggregate is equal to or greater than 0.15 μm and equal to or less than 0.5 μm; the specific surface area of the ruthenium aggregate is equal to Greater than 20 m ² / g and equal to or less than 50 m ² / g.

The present invention performs the wet grinding step by first performing a high-energy mechanical grinding step, except that the niobium raw material can be honed by a high-energy mechanical grinding method into a micron-sized niobium aggregate obtained by agglomerating a plurality of nano-sized niobium particles. The high mechanical energy can also induce a portion of the ruthenium agglomerate to be amorphized; and the subsequent wet milling step again causes the micron-sized ruthenium agglomerate to be ground to agglomerated by a plurality of nano-sized cerium particles.矽 aggregates. The ruthenium-based electrode material obtained by the method reduces the primary particle diameter of the nano sized ruthenium particles and the secondary particle diameter of the ruthenium aggregate, shortens the diffusion distance of lithium ions in the lithium ion battery, and the ruthenium obtained by the method The base electrode material changes the surface structure of the ruthenium raw material, thereby changing the type of the ruthenium aggregate reacting with lithium ions during charge and discharge, thereby improving the cycle characteristics and the capacitance retention rate of the lithium ion battery.

Specifically, after the micro-scale cerium agglomerate is ground using a modifier in the wet milling step, a modified cerium aggregate is obtained, and then dried at a suitable temperature (for example, 80 ° C to 500 ° C). The ruthenium-based electrode material is obtained. Wherein, the modifier is a reagent capable of chemically modifying the surface of the micron-sized cerium agglomerate during the grinding process, so that the surface of the prepared ruthenium-based electrode material is subjected to a specific chemical functional group. Group modification. For example, the modifier for chemically modifying the surface of the micron-sized ruthenium agglomerate during wet milling may include, but is not limited to, ethanol, glucose, sucrose, fructose ), starch, citric acid, glucosamine, L-alanine, oleic acid, oleylamine, cellulose acetate , carboxymethyl cellulose, α-D-cellobiose octaacetate, heptylboronic acid, 1,4-dimethoxy-3 -(1,4-dimethoxy-3-methylnaphthalen-2-yl)boronic acid, 2,4,6-trifluorophenylboronic acid , cysteine, acetylcysteine, dithiothreitol, ethyl phosphite, or a combination thereof, may be a hydroxyl group (-OH, specifically Is -C-OH, -B-OH, or -P-OH, etc.), alkoxy (-OR), carboxyl (-COOH), phosphonic acid (-PO(OH), or -PO(OH) ₂ ), mercapto (-SH), amino (-NH ₂ , or -NH), ammonia A chemical functional group such as a -acid group (-CH(NH ₂ )COOH) is modified on the surface of the ruthenium-based electrode material, but is not limited thereto. The surface of the modified ruthenium aggregate can form a good solid electrolyte interface (SEI) with the electrolyte during the first charge and discharge process. Preferably, the modifier may further comprise water or N-methylpyrrolidone (NMP), but is not limited thereto. For example, the modifier may be a combination of glucose and NMP, a combination of cellulose acetate and ethanol, a combination of cellulose acetate and water, a combination of carboxymethyl cellulose and NMP, or an alpha-D-cellobiose. a combination of octaacetate and NMP, and the like. The weight ratio of the modifier to the micron-sized cerium agglomerate is from 1:5 to 2:1.

According to the present creation, in the high-energy mechanical grinding step, the ratio of the ball to the ball refers to the mass ratio of the grinding ball to the raw material of the crucible; in the wet grinding step, the ratio of the ball to the ball refers to the agglomeration of the grinding ball relative to the micron-sized crucible. The mass ratio of the object. For example, the ball ratio of the high energy mechanical grinding step is 5:1 to 25:1; preferably, the ball ratio of the high energy mechanical grinding step is 10:1 to 20:1. For example, the ball ratio set in the wet grinding step is 10:1 to 1:1; preferably, the ball ratio set in the wet grinding step is 5:1 to 2:1.

In the high-energy mechanical grinding step, the grinding balls used may be stainless steel beads or zirconia beads (ZrO ₂ ), and the particle diameter may be 3 mm to 10 mm, but is not limited thereto.

Preferably, the high-energy mechanical grinding step is carried out at a temperature of 150 rpm to 500 rpm at room temperature for a grinding time of 3 hours to 15 hours.

In the wet milling step, the grinding balls used may be zirconia beads (ZrO ₂ ), and the particle diameter may be 0.2 mm to 10 mm, but is not limited thereto.

Preferably, the wet milling step is carried out at a temperature of from 150 rpm to 500 rpm at room temperature for a period of from 2 hours to 20 hours.

The present invention further provides a ruthenium-based electrode material comprising a ruthenium aggregate comprising a plurality of surface cold-welded nano ruthenium particles having a surface of at least one hydroxyl group, an alkoxy group, a carboxyl group, a functional group modification of a phosphonic acid group, a fluorenyl group, an amino group, an amino acid group, or a combination thereof; wherein the primary particle diameter of the nano sized particles is less than 0.1 μm; and the median diameter of the cerium aggregate is equal to or greater than 0.15 μm And equal to or less than 0.5 μm; the specific surface area of the cerium aggregate is equal to or greater than 20 m ² /g and equal to or less than 50 m ² /g.

By modifying a suitable functional group on the surface of the ruthenium aggregate, a solid electrolyte interface can be formed in the negative electrode of the lithium ion battery to help preferential diffusion of lithium ions into the ruthenium aggregate to generate a lithiation reaction, and the foregoing The adhesion of the ruthenium aggregate to the adhesive resin contained in the electrode, thereby providing good battery characteristics.

Preferably, the foregoing ruthenium aggregate has a porous structure.

Preferably, the ruthenium agglomerate has a nanocrystalline-amorphous composite structure, that is, the ruthenium aggregate has both a nanocrystalline state and an amorphous state; and the nano morphological ridge having an unordered arrangement surrounds the nanometer. The crystalline nanocrystalline-amorphous composite structure around the ordered arrangement of the ruthenium can expand the interfacial region of the ruthenium aggregate reacting with lithium ions during charge and discharge, and can reduce the energy difference of the lithiation reaction. It inhibits the formation of lithium pentoxide (Li ₁₅ Si ₄ ) crystals during charge and discharge, thereby improving the cycle characteristics and capacitance retention of lithium ion batteries.

Preferably, in the anthraquinone aggregate, the ratio of the amorphous form to the total area of the amorphous form and the nanocrystalline form is 25% to 75%. More preferably, the amorphous form of germanium accounts for 50% to 75% of the sum of the amorphous form and the crystalline area of the nanocrystalline state.

Preferably, when ethanol is used as the modifier, the surface of the ruthenium aggregate is modified with an OCH ₂ CH ₃ group. By modifying the OCH ₂ CH ₃ group on the surface of the foregoing ruthenium aggregate, a good solid electrolyte interface can be formed on the surface of the ruthenium aggregate, so that lithium ions easily diffuse into the ruthenium aggregate to generate a lithiation reaction. Improve battery characteristics.

Further, the present invention further provides a negative electrode for a lithium ion battery comprising the aforementioned ruthenium based electrode material. Specifically, the negative electrode further includes at least one adhesive resin and at least one auxiliary conductive agent.

For example, the adhesive resin may include poly(acrylic acid), carboxymethyl cellulose (CMC), styrene butadiene rubber (SBR), but not only Limited to this.

For example, the conductive agent may include, but is not limited to, carbon black, carbon tube, carbon fiber, graphite, and the like.

Preferably, the ruthenium based electrode material is used in an amount of from 5 wt% to 75 wt% based on the total weight of the entire negative electrode.

In addition, without affecting the effect of the negative electrode for a lithium ion battery of the present invention, other auxiliary additives such as lithium hydroxide (LiOH) and oxalic acid (H ₂ C) may be added to the negative electrode depending on different use requirements. ₂ O ₄ ), but not limited to this.

In addition, the present invention further provides a lithium ion battery comprising: the foregoing anode, cathode and electrolyte for a lithium ion battery.

Hereinafter, those skilled in the art can easily understand the advantages and effects that can be achieved by the present invention from the following embodiments. Therefore, it is to be understood that the descriptions of the present invention are only intended to illustrate the preferred embodiments and are not intended to limit the scope of the present invention. The content of this creation.

The instrument models used in the following examples: 1. Planetary grinder: Retsch PM 400; 2. Scanning electron microscope: Hitachi S-3400 SEM; 3. Field emission scanning electron microscope: Carl Zeiss AURIGA CrossBeam FIB/SEM Workstation; Penetrating electron microscope: JEOL JEM-2100F TEM; 5. X-ray diffractometer: Rigaku Ultima IV; 6. Instant XRD: including 2D CCD sensor (Rayonix, Quantum 225), and synchrotron accelerator (SPBL- 12B1 in Synchrotron facility Spring-8); 7. X-ray photoelectron spectrometer: ULVAC PHI 5000 VersaProbe XPS; 8. Laser particle size analyzer: Horiba LA960; 9. Specific surface area analyzer: Micromeritics ASAP 2020; 10. Tiny Current battery automatic charge and discharge test host: AcuTech Systems BAT-750B; 11. Electrochemical analyzer: Eco Chemie Autolab PGSTAT30.

The materials used in the following examples: 1. Alfalfa raw material: 99.9%, 10 micron, purchased from Fuzhou Hokin Chemical Technologu Co.; 2. Ethanol: purchased from Jingming Chemical Co., Ltd.; 3. Glucose: purchased from Sigma-Aldrich Co 4. NMP: purchased from Taiwan Bolu Co., Ltd.; 5. Cellulose acetate: purchased from Sigma-Aldrich Co.; 6. Carboxymethyl cellulose: purchased from Sigma-Aldrich Co.; 7. α-D - cellobiose octaacetate: purchased from Sigma-Aldrich Co.; 8. Carbon black: Super P, purchased from MMM, Belgium; 9. Polyacrylic acid: purchased from Sigma-Aldrich Co.; Diene rubber: purchased from Zeon Co.; 11. Lithium hydroxide: purchased from Panreac Chemicals; 12. Carbon fiber: VGCF, available from SHOWA DENKO KK; 13. Graphite: FSN, available from Shanghai Shanshan Tech Co.

Example 1 Base electrode material

The commercial enamel raw material and a plurality of stainless steel beads having a diameter of 3 mm are placed in a 500 ml stainless steel bottle, wherein the mass ratio of the stainless steel beads to the bismuth raw material is 20:1; and the stainless steel bottle is filled with argon gas. Sealed in the glove box. Then, using a planetary mill to perform high-energy mechanical grinding at room temperature at 300 rpm for 9 hours, a one-micron ruthenium condensate is obtained; the micron-sized ruthenium condensate and a plurality of ZrO ₂ beads having a diameter of 2 mm are The ethanol as a modifier is placed in a polypropylene tank, wherein the mass ratio of the ZrO ₂ beads to the micron-sized cerium agglomerates is 20:1. Then, after wet-grinding at room temperature at a rotation speed of 250 rpm for 6 hours, a lumps of aggregates are removed, the ZrO ₂ beads are removed, followed by separation steps such as washing with alcohol, centrifugation, removal of the supernatant, and separation. The ruthenium-based electrode material of Example 1 was completed by drying the ruthenium aggregate under a vacuum of 120 ° C for 12 hours.

Example 2 Base electrode material

The method used in Example 2 was similar to the method of preparing the ruthenium-based electrode material of Example 1, except that the modifier (ethanol) of Example 1 was changed to a NMP solution in which glucose was dissolved, and the glucose solution was used. The concentration is 10 wt% (based on total weight of glucose and NMP of 100 wt%).

Example 3 Base electrode material

The method used in Example 3 is similar to the method of preparing the ruthenium-based electrode material of Example 1, except that the modifier of Example 1 is changed to an ethanol solution in which cellulose acetate is dissolved, and the cellulose acetate solution is used. The concentration is 10 wt%.

Example 4 Base electrode material

The method used in Example 4 was similar to the method of preparing the ruthenium-based electrode material of Example 1, except that the modifier of Example 1 was changed to an aqueous solution in which cellulose acetate was dissolved, and the concentration of the cellulose acetate solution was changed. It is 10 wt%.

Example 5 Base electrode material

The method used in Example 5 was similar to the method of preparing the ruthenium-based electrode material of Example 1, except that the modifier of Example 1 was changed to NMP in which α-D-cellobiose octaacetate was dissolved. A solution, and the α-D-cellobiose octaacetate solution concentration was 10 wt%.

Example 6 Base electrode material

The method used in Example 6 is similar to the method of preparing the ruthenium-based electrode material of Example 1, except that the modifier ethanol of Example 1 is changed to a NMP solution in which carboxymethylcellulose is dissolved, and the The concentration of the carboxymethylcellulose solution was 10 wt%.

The ruthenium-based electrode material of Reference Example 1 (ie, the commercial ruthenium raw material of Example 1)

Reference example 2 Base electrode material

The method used in Reference Example 2 was substantially the same as the method of preparing the ruthenium-based electrode material of Example 1, and the main difference was that the commercial ruthenium raw material was subjected only to the high-energy mechanical polishing step without the wet-grinding step.

Reference example 3 Base electrode material

The method employed in Reference Example 3 was carried out by subjecting the commercial crucible raw material to a wet grinding step as in Example 1, without performing a high-energy mechanical grinding step. The method is mainly as follows: a commercial ruthenium raw material and a plurality of ZrO ₂ beads having a diameter of 2 mm and ethanol as a modifier are placed in a polypropylene tank, wherein the mass ratio of the ZrO ₂ beads to the commercial ruthenium raw material is 20:1. Then, it was wet-milled at room temperature at a rotation speed of 250 rpm for 10 hours, filtered, and dried under vacuum at 120 ° C for 12 hours to complete the ruthenium-based electrode material of Reference Example 3.

Reference example 4 Base electrode material

The method used in Reference Example 4 was carried out by mixing a commercial hydrazine raw material and a modifying agent (NMP solution having a concentration of 10 wt% of glucose) without filtration, drying under vacuum at 120 ° C for 12 hours, followed by hydrogen / The carbonization treatment was carried out for 1 hour at a temperature of 800 ° C in an argon atmosphere.

analysis 1 : The appearance of the ruthenium based electrode material

The ruthenium-based electrode materials of Reference Examples 1 to 3 and Example 1 were observed using a scanning electron microscope (SEM) or a field emission scanning electron microscope (FIB-SEM). The shape of the base electrode material.

Referring to FIG. 1A, which is a SEM photograph of Reference Example 1 at a magnification of 500 times, it can be seen from FIG. 1A that the primary particles of the cerium particles in Reference Example 1 exhibit an irregular sheet-like pattern. 1B and FIG. 1C are SEM photographs of Reference Example 2 at magnifications of 5000 (5 k) and magnifications of 50000 (50 k), respectively. It can be seen from FIG. 1B and FIG. 1C that the high-energy mechanical grinding step, the reference group 2 The electrode material is formed by agglomerating primary particles of a plurality of nano-sized cerium particles to form micron-sized cerium aggregates, and pores are formed between a plurality of primary particles during cold welding of primary particle aggregation, and the bismuth-based electrode material may be added. The specific surface area in contact with the electrolyte. 1D and FIG. 1E are SEM photographs of Reference Example 3 at 20,000 magnifications and 50,000 magnifications, respectively. From FIG. 1D and FIG. 1E, it can be seen that the wet-grinding step, the ruthenium-based electrode material of Reference Example 3 The primary particle diameter is smaller than the primary particle diameter of the ruthenium particles of Reference Example 1, and the particle size of the ruthenium aggregate in the ruthenium-based electrode material of Reference Example 3 is larger than that of the ruthenium-based electrode material of Reference Example 2. The particle size is smaller. 1F and FIG. 1G are SEM photographs of Example 1 at a magnification of 20,000 times and a magnification of 50,000 times, respectively, and FIG. 1F and FIG. 1G show that the primary particles of the nano-particles in the ruthenium-based electrode material of Example 1 are in size and The aspect was similar to the primary particles of the ruthenium particles of Reference Example 2, but the size of the ruthenium aggregate in the ruthenium-based electrode material of Example 1 was significantly smaller than that of Reference Example 2. From this, it can be seen that the wet milling step is carried out after the high-energy mechanical polishing step, and the agglomeration of the micron-sized cerium agglomerates can be formed by a wet grinding means to provide an appropriate agglomeration energy to form the agglomerate of the first embodiment.

Further, the form of Example 1 was observed using a high-resolution transmission electron microscope (TEM), and the results are shown in Fig. 2 . It can be confirmed from Fig. 2 that the nanocrystals of the crucible in the first embodiment are surrounded by the amorphous layered germanium on the random plane to form a nanocrystalline-amorphous composite structure, and the circle in Fig. 2 is indefinite. Formality. It can be seen that in the process of repeated deformation, cold welding and pulverization of the bismuth raw material in the high-energy mechanical grinding step, the cerium particles originally belonging to the ordered arrangement of the crystalline state can be partially converted into the disordered argon. The ruthenium-based electrode material of Example 1 was simultaneously provided with a nanocrystalline-amorphous composite structure of a nanocrystalline state and an amorphous state.

analysis 2 : XRD analysis

3, the crystal phase structure of the ruthenium-based electrode materials was confirmed by X-ray diffractometer (XRD) from the bottom to the top in the reference example 1, reference example 3, reference example 2, and example 1. As shown in Fig. 3, in the XRD pattern, the diffraction peak at 28.45 矽 represents the crystal face of the ruthenium (111), the diffraction peak of 47.31 矽 represents the crystal face of ruthenium (220), and the diffraction peak of 56.13 矽 represents the crystal of ruthenium. Face (311).

It can be seen from FIG. 3 that in the XRD patterns of the ruthenium-based electrode materials of Reference Example 2 and Example 1, especially the ruthenium-based electrode material of Example 1, the peak shapes of the above three specific diffraction peaks are wider and relatively strong. Lower, thus showing that the ruthenium-based electrode materials of Reference Example 2 and Example 1 have less crystallinity, and the ruthenium-based electrode material of Example 1 has the least crystal volume.

It can be seen that the XRD analysis results are consistent with the SEM image results of the ruthenium-based electrode material of Example 1 of FIG. 2, both of which can show that the ruthenium-based electrode material of Example 1 has both a crystalline phase and an amorphous state. Nanocrystalline-amorphous composite structure. It can be seen that the high energy mechanical grinding step can provide high energy to the ground niobium raw material, so that the niobium raw material which is originally in a crystalline state is ground into a micron-sized niobium agglomerate having a partial amorphous state.

analysis 3 : XPS analysis

The ruthenium-based electrode materials of Reference Examples 1 to 3 and Example 1 were confirmed by X-ray photoelectron spectroscopy (XPS) to determine the surface composition characteristics of the ruthenium-based electrode materials. The bonding conditions of Si(2p), C(1s) and O(1s) on the surface of the ruthenium-based electrode material of Reference Example 1, Reference Example 2, Reference Example 3, and Example 1 were analyzed by XPS, and the experimental results were compiled. In Table 1 below.

As is apparent from the experimental results of Table 1 below, the surface of Reference Example 1 had a relatively high ratio of cerium oxide (SiO ₂ ). However, the surface of the ruthenium-based electrode material of Reference Example 2, Reference Example 3, and Example 1 has a relatively high proportion of 矽Moule ratio, whether through a high-energy mechanical grinding step or/and a wet-grinding step. It can be seen that in the high-energy mechanical grinding step and the wet grinding step, the bismuth component in the ruthenium-based electrode material can be continuously refined and a new ruthenium surface is produced, so that the molar ratio can be relatively increased.

On the other hand, it is apparent from the experimental results in Table 1 below that the surface of the ruthenium-based electrode material of Reference Example 3 and Example 1 had a high C-O bonding ratio due to the ethanol contained in the wet milling step.

In addition, the ruthenium-based electrode materials of Reference Example 1, Reference Example 2, Reference Example 3, and Example 1 are known in the X-ray photoelectron energy spectrum of O(1s), and the sulfhydryl groups of Reference Example 3 and Example 1 are known. The O(1s) peak of the electrode material is slightly shifted to the low bond, and it can be inferred that after the wet grinding step, ethanol forms Si-OCH ₂ on the surface of the base electrode material of Reference Example 3 and Example 1. CH ₃ bonding. Table 1: Results of XPS experiments of Reference Examples 1 to 3 and Example 1. Reference Example 1 Reference Example 2 Reference Example 3 Example 1 Si mole ratio (mole%) 47.4 67.1 66.7 65.3 SiO2 molar ratio (mole%) 52.6 32.9 33.3 34.7 CC bonding ratio (%) 83.9 91.5 77.3 72.4 CO bonding Proportion (%) 10.6 8.5 16.1 27.6

analysis 4 : Particle size analysis

Reference Example 1, Reference Example 2, Reference Example 3, and ruthenium-based electrode materials of Examples 1 to 6 The average particle diameter of the primary particle diameter of the ruthenium particles in the ruthenium-based electrode materials was measured using a laser particle size analyzer. The median diameter value (D50) of the ruthenium aggregate obtained by aggregating the ruthenium particles, and the specific surface area of the ruthenium-based electrode materials measured by using a specific surface area analyzer, reference example 1, reference example 2, reference The measurement results of Example 3 and Example 1 are shown in Table 2 below.

In general, the smaller the particle size, the larger the specific surface area. However, in particular, since the niobium raw material is continuously refined and surface-deformed by repeated cold welding and pulverization in the high-energy mechanical grinding step, the specific surface area of Reference Example 2 has no specific surface area of Reference Example 3 in which cold-welded particles are not formed on the surface. Bigger. As is apparent from Table 2 below, Example 1 subjected to the high energy mechanical grinding step and the wet milling step had the largest specific surface area. Similarly, in the ruthenium-based electrode materials of Examples 2 to 6, the average particle diameters of the primary particle diameters of the ruthenium particles are less than 0.1 μm, and the median diameter values (D50) of the ruthenium aggregates are all From 0.3 microns to 0.5 microns, and the specific surface area of the ruthenium aggregates are between 20 m ² /g and 40 m ² /g. Table 2: Average particle diameter and specific surface area of the ruthenium-based electrode materials of Reference Examples 1 to 3 and Example 1. Property Reference Example 1 Reference Example 2 Reference Example 3 Example 1 Primary particle diameter (micrometer) Less than 20 Less than 0.15 Less than 0.5 Less than 0.1 Secondary particle diameter of the secondary particle diameter (micrometer) 10 1 to 5 0.4 0.3 to 0.5 Specific surface area (m2/g) 2.88 19.67 15.98 32.73

Example 7 to 15 Reference example 5 to 9 Negative electrode and battery thereof

The electrode material slurry of Reference Example 5 to Reference Example 8 and Example 7 to Example 12 was prepared by using the ruthenium-based electrode materials of Reference Example 1 to Reference Example 4 and Examples 1 to 6 in the same manner as the following formulation conditions. body. Based on the total solids of the whole electrode material slurry, the amount of each of the ruthenium-based electrode materials is 65 wt%, the amount of carbon black is 20 wt%, and the amount of polyacrylic acid is 8 wt%, and the styrene butadiene rubber The amount is 5 wt%, and the amount of lithium hydroxide is 2 wt%. The electrode material slurry was formed by adding a proper amount of deionized water to the planetary mixer according to the above ratio of the components and stirring at 500 rpm for 60 minutes.

Further, the electrode material slurry of Example 13 and Example 14 was prepared in the same manner as the following using the ruthenium-based electrode materials of Example 1 and Example 2 in that order. Based on the total solids of the whole electrode material slurry, the amount of each of the ruthenium-based electrode materials is 9.24 wt%, the amount of graphite is 80 wt%, and the amount of carbon black and VGCF is 3.5 wt%, polyacrylic acid, styrene. The common amount of butadiene rubber and carboxymethyl cellulose was 7.26 wt%. The electrode material slurry of Example 13 and Example 14 was formed by adding the appropriate ratio of the above components to an appropriate amount of deionized water to the planetary mixer and stirring at 500 rpm for 60 minutes.

Further, the electrode material slurry of Reference Example 9 and Example 15 was prepared in the same manner as the following using the ruthenium-based electrode materials of Reference Example 1 and Example 1. Based on the total solids of the whole electrode material slurry, the amount of each of the ruthenium-based electrode materials is 32.5 wt%, the amount of graphite is 32.5 wt%, and the amount of carbon black is 20 wt%, polyacrylic acid, styrene butadiene. The rubber and carboxymethyl cellulose are used together in an amount of 15% by weight. The electrode material slurry of Reference Example 9 and Example 15 was formed by adding the appropriate amount of each of the components and the amount of deionized water to the planetary mixer and stirring at 500 rpm for 60 minutes.

The foregoing electrode materials slurry of Reference Examples 5 to 9 and Examples 7 to 15 were cast on a copper foil sheet, baked in an oven at 90 ° C for 1 hour, and then rolled into Reference Examples 5 to 9, and implemented. Examples 7 to 15 are negative electrode electrodes for lithium ion batteries.

The negative electrode for a lithium ion battery, the lithium flakes using the reference examples 5 to 9 and the examples 7 to 15 were opposite electrodes, a microporous separator (Celgard 2300), and 1 volume of molar concentration (M) lithium hexafluorophosphate (LiPF). ₆ ), ethylene carbonate (EC), dimethyl carbonate (DMC) and fluorinated ethylene carbonate (FEC) electrolyte preparation international standard model 2032 test button battery And all battery construction and sealing are done in an argon-filled glove box.

analysis 5 : Battery characteristics analysis

The first to third charge and discharge analyses were performed using the batteries including the negative electrodes of Reference Examples 5 to 7 and Example 7 at 25 ° C: at a constant current of 200 milliamperes (mA) and a potential window of 0.02. Under the conditions of volts (V) to 1.5 volts (V), the first to third charge and discharge test results are sequentially presented in the relationship between voltage and capacitance in Figure 4 up and down. The steps of completing the first to third charge and discharge cycles of the batteries are the battery formation steps.

As can be seen from FIG. 4, in the graph of the relationship between the voltage and the capacitance of the first charge and discharge of the battery including the negative electrode of Example 7, the curve was significantly inclined, and the battery including the negative electrode of Reference Examples 5 to 7 was It is apparent that the plateau is different, and it is shown that the battery including the negative electrode of Example 7 has a voltage difference at the time of charge and discharge smaller than that of the battery including the negative electrodes of Reference Examples 5 to 7. The battery including the negative electrode of Example 7 also had a clearly inclined curved section at the second and third charge and discharge. The experimental results show that since the nano-crystals in the ruthenium-based electrode material of Example 1 are surrounded by amorphous ruthenium, and the surface of the ruthenium aggregate contained in the ruthenium-based electrode material of Example 1 is modified with ethanol in the wet-grinding step, Therefore, the foregoing characteristics affect the reaction of the electrode during delithiation and lithiation during charge and discharge, and therefore the battery including the electrode of Example 7 has good electrochemical characteristics.

In addition, Reference Examples 5 to 7 comprising a negative electrode, and Examples 7 to 12 of the first embodiment of such a battery discharge capacity (1 ^st discharge capacity) of the charge-discharge capacity test, the charge capacity (1 ^st charge capacity) and the initial coulombic efficiency (1 ^st Columbic efficiency), the 50th charge capacity (50 ^th charge capacity) and the stability of the capacitance (capacity retention) listed in table 3. The first Coulomb efficiency is the ratio of the first charge capacity to the first discharge capacity, and the capacitance stability is the ratio of the first charge capacity to the 50th charge capacity.

From the results of Table 3, it is understood that Examples 7 to 12 prepared from the ruthenium-based electrode materials of Examples 1 to 6 are superior in performance of capacitance stability to the ruthenium-based electrode materials of Reference Examples 1 to 4. Reference Example 5 to Reference Example 8 were prepared. Taking the ruthenium-based electrode material of Example 1 as an example, since the Si-OCH ₂ CH ₃ bond is formed on the surface of the ruthenium-based electrode material to affect the formation of SEI, it can contribute to the improvement of the negative electrode of Example 7. The battery's capacitance stability.

Table 3: Test results of the first charge and discharge and the 50th charge of the batteries of Reference Examples 5 to 8 and the negative electrodes of Examples 7 to 12.      First discharge capacity (mAh/g) First charge capacity (mAh/g) First coulombic efficiency (%) 50th charge capacity (mAh/g) Capacitance stability (%) Reference example 5 2323 1709 73.6 Unchargeable and dischargeable Up to 50 times -- Reference Example 6 3375 2429 72.0 466 19.2 Reference Example 7 4005 3555 88.8 2203 62.0 Reference Example 8 4018 3375 84.0 291 8.6 Example 7 3981 3439 86.4 2403 69.9 Example 8 3017 2687 89.1 2025 75.4 Example 9 2500 2205 88.2 1656 75.1 Example 10 2459 2142 87.1 1548 72.3 Example 11 1992 1773 89.0 1502 84.7 Example 12 2377 2031 85.4 1475 72.6

The discharge capacity, the charge capacity, and the first coulombic efficiency, the 50th charge capacity, and the capacitance stability of the first charge and discharge capacity test of the batteries of Reference Example 9 and Examples 13 to 15 are shown in Table 4 below. From Table 4, the comparison results of Example 15 and Reference Example 9 show that the battery of Example 15 prepared from the ruthenium-based electrode material of Example 1 had the first discharge capacity, the first charge capacity, the first coulombic efficiency, and the first The 50-charging capacity and the capacitance stability were superior to those of the battery of Reference Example 9 prepared from the ruthenium-based electrode material of Reference Example 1. Table 4: Test results of the first charge and discharge and the 50th charge of the battery including the negative electrode of Reference Example 9 and Examples 13 to 15.      First discharge capacity (mAh/g) First charge capacity (mAh/g) First coulombic efficiency (%) 50th charge capacity (mAh/g) Capacitance stability (%) Example 13 662 597 90.2 533 89.3 Implementation Example 14 638 584 91.5 503 86.1 Example 15 2024 1771 87.5 1443 81.5 Reference Example 9 1718 1465 85.3 396 27.0

In addition, the first three cycles of cyclic voltammetry (CV) were performed using the batteries containing the negative electrodes of Reference Examples 5 to 7 and Example 7 at 25 ° C: 0.005 V to 2.0 V at the potential window. The battery CV test results including the negative electrodes of Reference Examples 5 to 7 and Example 7 were sequentially shown in the relationship between voltage and current of FIGS. 5A to 5D under the condition that the scanning speed was 0.1 mV/s. It can be clearly seen that the battery including the negative electrode of Example 7 has the best curve overlap in the first three CV tests, indicating that the battery including the negative electrode of Example 7 is stable to the fastest, and thus has the best stability and Cycle characteristics. Further, as can be seen by comparing FIGS. 5A to 5D, the battery including the negative electrode of Example 7 has an oxidation/reduction waveform starting from 0.3 V to 0.6 V different from those of the batteries including the negative electrodes of Reference Examples 5 to 7, and the display thereof includes The battery of the negative electrode of Example 7 and the batteries including the negative electrode of Reference Examples 5 to 7 had different lithiation/delithiation behavior. Because the nano-rhenium crystal in the ruthenium-based electrode material of Example 1 is surrounded by amorphous ruthenium, thereby affecting the behavior of lithiation and delithiation during charge and discharge; and at 0.3 V and 0.5 V The reduction peak may be caused by a two-step delithiation from Li _x Si.

The number of charge and discharge cycles was measured using the batteries including the negative electrodes of Reference Examples 5 to 7 and Example 7: under the conditions of a constant current of 200 mA and a potential window of 0.02 V to 1.5 V, the number of charge and discharge cycles of FIG. The relationship with the capacitance is presented. As can be seen from Fig. 6, the capacitance of the batteries including the negative electrodes of Reference Examples 5 and 6 was significantly degraded when the number of charge and discharge cycles was 10 times. It is presumed that the reason is that the ruthenium raw material contained in Reference Example 1 used in the battery of Reference Example 5 and the reference Example 2 ruthenium-based electrode material used in Reference Example 6 are all in the micron-scale size, both of which are in the charge and discharge cycle of the battery. In the case of severe smashing, the capacitor retention rate is poor. In contrast, the battery including the negative electrode of Example 7 may have a capacitance retention ratio of about 70% when the number of cycles is 50, which is superior to that of the battery including the negative electrode of Reference Example 7 when the number of cycles is 50. 62% capacitance retention.

In addition, during the first charge and discharge and the second discharge, the XRD patterns of the batteries including the negative electrodes of Reference Example 5 and Example 7 were measured by in-situ XRD (in situ XRD), as shown in FIG. 7A and FIG. Shown in 7B. The battery including the negative electrode of Reference Example 5 can be markedly representative of representative peaks representing the crystal face (211), the crystal face (220), and the crystal face (310) of Li ₁₅ Si ₄ . On the other hand, the battery including the negative electrode of Example 7 was almost impossible to measure the aforementioned representative peak. From this, it can be seen that in the reaction of multiple lithiation and delithiation, the repeated conversion of amorphous Li _X Si and crystalline Li ₁₅ Si ₄ is disadvantageous for the performance of the capacitance capacity ratio.

analysis 6 : Parity spacing analysis

In addition, during the first charge and discharge, the XRD patterns of the batteries including the negative electrodes of Reference Example 9 and Example 15 were measured by an instant XRD, and the graphite crystal faces of FIG. 8a were derived from the results of XRD. Pitch diagram. During the 50th charge and discharge process, the XRD patterns of the batteries including the negative electrodes of Reference Example 9 and Example 15 were measured again using an instant XRD, and the graphite crystal faces as shown in Fig. 8b were derived from the results of XRD. Pitch diagram. It can be seen from Fig. 8a and Fig. 8b that when graphite is added as a conductive agent, the ruthenium-based electrode material of the present invention can be used to promote lithium ion preferentially in the first charge-discharge process or after multiple charge-discharge processes. Reacting with the ruthenium-based electrode material of the present invention can show that the ruthenium-based electrode material of the present invention maintains good reaction characteristics for lithium ion binding activity after repeated charge and discharge, and thus can be beneficial for improving battery life.

analysis 7 : XPS analysis

The XPS spectra of the Si 2p before the formation of the batteries including the negative electrodes of Example 12 and Reference Example 8 were sequentially measured, and the results are shown in Figs. 9A and 10A. It can be seen that the negative electrodes of Example 12 and Reference Example 8 were measured from the surface of the negative electrodes to the inside of the negative electrodes, and the depth of each measurement was about 15 nm, and the negative electrodes of each depth had a 矽 characteristic before formation. peak. After the formation, the negative electrodes of Example 12 and Reference Example 8 were again measured by XPS, and the internal electrodes were measured from the surface of the negative electrodes, and the XPS spectrum of Si 2p was measured as shown in FIGS. 9B to 10B. Shown. It can be found that the 矽 characteristic peak of Example 12 is still significantly retained compared to Reference Example 8, and the experimental results can be reconfirmed that the ruthenium-based material treated by the modifier can change the characteristics of the formed SEI film and can help lithium. Ion diffusion into the ruthenium-based electrode material produces lithiation and delithiation reactions, which makes the capacitance stability of Example 12 in Table 3 significantly better than that of Reference Example 8, and has good coulombic efficiency and cycle charge. Discharge performance. In addition, the XPS spectra of the batteries of the negative electrodes of Examples 8, 11 and 12 before the formation of the C 1s were measured, and the measurement results were sequentially shown in FIGS. 11A to 13A, and it was found that the ruthenium treated by the different modifiers was found. The C 1s XPS pattern of the negative electrode of the base material is similar before the formation, but the XPS spectra of the C 1s of the cells are significantly different after the formation, and the measurement results are sequentially shown in FIG. 11B to FIG. 13B . From this, it was confirmed that the ruthenium-based materials contained in the negative electrodes of Examples 8, 11, and 12 treated with different modifiers can change the characteristics of the formed SEI film.

In summary, the results of the above analysis show that the ruthenium-based electrode materials of Examples 1 to 6 have both a suitable primary particle size range of nano-ruthenium particles, an appropriately sized ruthenium aggregate, an appropriate specific surface area ruthenium aggregate, and The surface of the anthracene aggregate is modified with an appropriate functional group. Therefore, the anodes of Examples 7 to 15 can be formed by using the ruthenium-based electrode materials of Examples 1 to 6, which can facilitate shortening the lithium ion diffusion distance, increase the reaction interface with lithium ions, and have the ruthenium aggregate simultaneously. Nanocrystalline and amorphous forms expand the interfacial region where lithium ions react during charge and discharge, reduce the energy difference of the lithiation reaction, inhibit the formation of Li ₁₅ Si ₄ crystals during charge and discharge, and further enhance lithium The cycle characteristics and capacitance retention of the ion battery.

Therefore, these batteries have good performance in the performance of the capacitance retention rate, and the small-sized ruthenium-based electrode materials obtained by the steps of high-energy mechanical grinding and wet grinding are more resistant to other nano sulfhydryl groups such as nanowires. The electrode material has the advantage of lower manufacturing cost, which further enhances the development potential of the base electrode material of the present invention.

The above-described embodiments are merely examples for convenience of description, but the embodiments are not intended to limit the scope of the patent application of the present invention; any other changes, modifications, etc. that have been completed without departing from the present disclosure should be included in This patent covers the scope of patents.

no.

1A to 1G are photographs of a scanning electron microscope of the ruthenium-based electrode materials of Reference Examples 1 to 3 and Example 1. 2 is a photograph of a high-resolution transmission electron microscope of the ruthenium-based electrode material of Example 1. 3 is an X-ray diffraction pattern of the ruthenium-based electrode materials of Reference Examples 1 to 3 and Example 1. Fig. 4 is a graph showing the relationship between the voltage and the capacitance of the first to third charge and discharge of the batteries of the negative electrodes of Reference Examples 5 to 7 and Example 7, respectively. Fig. 5A is a graph showing the relationship between voltage and current obtained by cyclic voltammetry of a battery including the negative electrode of Reference Example 5. Fig. 5B is a graph showing the relationship between voltage and current obtained by cyclic voltammetry of a battery including the negative electrode of Reference Example 6. Fig. 5C is a graph showing the relationship between voltage and current obtained by cyclic voltammetry of a battery including the negative electrode of Reference Example 7. Fig. 5D is a graph showing the relationship between voltage and current obtained by cyclic voltammetry of a battery including the negative electrode of Example 7. Fig. 6 is a graph showing the relationship between the number of charge and discharge cycles and the capacitance of the batteries including the negative electrodes of Reference Examples 5 to 7 and Example 7, respectively. Fig. 7A is an XRD pattern of a battery including the negative electrode of Reference Example 5, which was measured by immediate XRD. Figure 7B is an XRD pattern of a battery comprising the negative electrode of Example 7 using immediate XRD measurements. Fig. 8A is a diagram showing the relationship of the interplanar spacing of the first charge and discharge processes of the batteries of the negative electrode of Reference Example 9 and Example 15 respectively. Fig. 8B is a diagram showing the relationship of the interplanar spacing of the 50th charge and discharge process of the batteries of the negative electrode of Reference Example 9 and Example 15 respectively. 9A is an XPS Si 2p analysis of the negative electrode of Example 12 before cell formation; and FIG. 9B is an XPS Si 2p analysis of the negative electrode of Example 12 after battery formation. Fig. 10A is an XPS Si 2p analysis of the negative electrode of Reference Example 8 before the battery formation; Fig. 10B is an XPS Si 2p analysis of the negative electrode of Reference Example 8 after the battery formation. 11A is an XPS C 1s analysis of the negative electrode of Example 8 before battery formation; and FIG. 11B is an XPS C 1s analysis of the negative electrode of Example 8 after battery formation. Figure 12A is an XPS C 1s analysis of the negative electrode of Example 11 prior to cell formation; Figure 12B is an XPS C 1s analysis of the negative electrode of Example 11 after cell formation. Figure 13A is an XPS C 1s analysis of the negative electrode of Example 12 prior to cell formation; Figure 13B is an XPS C 1s analysis of the negative electrode of Example 12 after cell formation.

no.

Claims (8)

A method for preparing a ruthenium-based electrode material, comprising the steps of: grinding a ruthenium raw material by a high-energy mechanical grinding method to obtain a one-micron ruthenium condensate; and mixing a micron-sized ruthenium condensate with a modifier to obtain a mixture. Grinding the mixture by wet milling to obtain a ruthenium-based electrode material; wherein the modifier comprises ethanol, glucose, sucrose, fructose, starch, citric acid, glucosamine, L-alanine, oleic acid, oleylamine, Cellulose acetate, carboxymethyl cellulose, α-D-cellobiose octaacetate, heptylboronic acid, 1,4-dimethoxy-3-methylnaphthalene-2-boronic acid, 2,4,6 -trifluorophenylboronic acid, cysteine, acetylcysteine, dithiothreitol, ethylphosphonic acid, or a combination thereof; the ruthenium-based electrode material comprises a ruthenium aggregate comprising a plurality of surfaces Cold-welded nano-powder particles; wherein the nano-powder particles have a primary particle diameter of less than 0.1 μm; the ruthenium aggregate median particle diameter is equal to or greater than 0.15 μm and equal to or less than 0.5 μm; The specific surface area is equal to or greater than 20 m ² /g and equal to or less than 50 m ² /g. A ruthenium-based electrode material comprising a ruthenium aggregate comprising a plurality of surface cold-welded nano ruthenium particles having a surface of at least one of a hydroxyl group, an alkoxy group, a carboxyl group, a sulfhydryl group, and an amino group a functional group modification of an amino acid group, a phosphonic acid group or a combination thereof; wherein the primary particle diameter of the nano-sized particles is less than 0.1 μm; the median diameter of the germanium aggregate is equal to or greater than 0.15 μm and equal to or less than 0.5 μm; the specific surface area of the ruthenium aggregate is equal to or greater than 20 m ² /g and equal to or less than 50 m ² /g; wherein the ruthenium aggregate has both a crystalline phase and an amorphous state, and the amorphous form accounts for The ratio of the morphology to the sum of the crystalline phases of the nanocrystals is 25% to 75%. The ruthenium-based electrode material according to claim 2, wherein the ruthenium aggregate has a porous structure. A negative electrode for a lithium ion battery comprising the ruthenium based electrode material of claim 2 or 3. The negative electrode according to claim 4, wherein the negative electrode further comprises at least one adhesive resin and at least one auxiliary conductive agent. The anode according to claim 5, wherein the fluxing agent comprises carbon black, carbon tube, carbon fiber, graphite, or a combination thereof. The anode according to any one of claims 4 to 6, wherein the ruthenium-based electrode material is used in an amount of 5 wt% to 75 wt% based on the total weight of the entire anode. A lithium ion battery comprising the anode, the cathode and an electrolyte for a lithium ion battery according to any one of claims 4 to 7.