CN101563797A - Copper-based energy storage device and method - Google Patents

Abstract

An energy storage device (100) is provided that includes a positive electrode material in electrical communication with a separator. The positive electrode material includes copper. The partition (104) has a first surface (106) defining at least a portion of a first compartment (110) and a second surface (108) defining a second compartment (112). The first compartment is in ionic communication with the second compartment via the partition. The separator has at least one of the following properties: the separator is a composite of alumina and a rare earth oxide, or the separator is a composite of alumina and a transition metal oxide, or the separator comprises a plurality of grains defining grain boundaries defining interstitial spaces, the interstitial spaces defined by the grain boundaries being free of sodium aluminate prior to initial charging of the energy storage device or free of a positive electrode material after initial charging of the energy storage device, or the separator comprises a continuous phase of an alkali metal ion conductor and a continuous phase of a ceramic oxygen ion conductor.

Description

Copper-based energy storage device and method

Cross References to Related Applications

This application claims priority and benefit from U.S. Provisional Application No. 60/870,843, filed December 19, 2006, entitled "ENERGY STORAGE DEVICE AND METHOD," which is hereby incorporated by reference in its entirety.

technical field

The present invention relates to molten salt electrochemical cells. The present invention relates to methods of using electrochemical cells. The invention relates to an energy storage device and an energy management device comprising the energy storage device.

Background technique

For rechargeable batteries, development work has been carried out using sodium for the negative electrode. Sodium has a reduction potential of 2.71 volts, is small in weight, relatively nontoxic, relatively abundant, available and low cost. Sodium is used in liquid form and its melting point is 98°C. It should be noted that thermal cycling, pressure differentials, and vibrations within the cell during use may in some cases damage the β-alumina separator electrode (BASE). Thus, thicker walls may impart better strength and durability to the BASE, but may degrade related performance due to increased electrical resistance due to thicker walls.

It may be desirable to have a molten salt electrochemical cell that has a different chemistry than existing electrochemical cells. It may be desirable to obtain energy storage devices that differ from existing approaches. It may be desirable to obtain energy storage devices that differ from existing devices.

Contents of the invention

According to an embodiment of the present invention, an energy storage device is provided. The energy storage device includes a positive electrode material in electrical communication with the separator. The positive electrode material includes copper. The partition has a first surface defining at least a portion of the first compartment and a second surface defining the second compartment. The first compartment is in ion communication with the second compartment via the partition. The separator has at least one of the following properties: the separator is a composite of alumina and a rare earth metal oxide; or the separator is a composite of alumina and a transition metal oxide; or the separator comprises a plurality of grains, the grain boundaries define interstitial spaces, and the interstitial spaces bounded by the grain boundaries are free of sodium aluminate prior to initial charge of the energy storage device or free of positive electrode material after initial charge of the energy storage device; or The plates comprise a continuous phase of an alkali metal ionic conductor and a continuous phase of a ceramic oxygen ionic conductor.

According to an embodiment of the present invention, there is provided a method comprising transporting sodium ions between a first compartment and a second compartment via a separator in electrical communication with a positive electrode material comprising copper. The separator has at least one of the following properties: the separator is a composite of alumina and a rare earth metal oxide; or the separator is a composite of alumina and a transition metal oxide; or the separator comprises a plurality of The grains, the grain boundaries define interstitial spaces, and the interstitial spaces bounded by the grain boundaries are free of sodium aluminate prior to initial charge of the energy storage device or free of positive electrode material after initial charge of the energy storage device; or the separator contains sodium ions The continuous phase of the conductor and the continuous phase of the ceramic oxygen ion conductor. The method also includes preventing copper from infiltrating interstitial spaces during sodium ion transport.

According to an embodiment of the present invention, an energy storage system is provided. The system includes bulkheads. The separator transports sodium ions between the first compartment and the second compartment. The separator is in electrical communication with the positive electrode material including copper. The separator has at least one of the following properties: the separator is a composite of alumina and a rare earth metal oxide; or the separator is a composite of alumina and a transition metal oxide; or the separator comprises a plurality of The grains, the grain boundaries define interstitial spaces, and the interstitial spaces bounded by the grain boundaries are free of sodium aluminate prior to initial charge of the energy storage device or free of positive electrode material after initial charge of the energy storage device; or the separator contains sodium ions The continuous phase of the conductor and the continuous phase of the ceramic oxygen ion conductor. The system also includes means to prevent copper from penetrating into the interstitial space during sodium ion transport.

Description of drawings

Figure 1 is a schematic diagram of an article according to one embodiment of the invention.

Figure 2 is a series of designs (Figures 2A-2J) for embodiments of the present invention.

Figure 3 is a graph of an example polarization curve according to an embodiment of the present invention.

Figure 4 is a performance graph of an example according to an embodiment of the present invention.

Figure 5 is a graph comparing examples and comparative samples according to one embodiment of the present invention.

Detailed ways

The present invention relates to molten salt electrochemical cells. The present invention relates to methods of using electrochemical cells. The present invention relates to energy storage devices and energy management devices including energy storage devices.

As used herein, a positive electrode material is a material that donates electrons during charging and has greater than about 5% by weight of the electrochemical reactants participating in the reaction on its reactive side as part of the redox reaction. As used in the specification and claims, any quantitative expression may be modified using approximate expressions, allowing the quantitative expression to be changed without altering the basic function to which it relates. Accordingly, a value modified by a term such as "about" is not to be limited to the precise value stated. In some cases, expressions of approximation may correspond to the precision of the instrumentation used to measure the value.

According to an embodiment of the present invention, an energy storage device is provided. The energy storage device includes a positive electrode material in electrical communication with the separator. The positive electrode material includes copper. The partition has a first surface defining at least a portion of the first compartment and a second surface defining the second compartment. The first compartment is in ion communication with the second compartment via the partition. The separator has at least one of the following properties: the separator is a composite of alumina and a rare earth metal oxide; or the separator is a composite of alumina and a transition metal oxide; or the separator comprises a plurality of grains, the grain boundaries delimit interstitial spaces, and the interstitial spaces delimited by the grain boundaries are free of sodium aluminate prior to initial charge of the energy storage device or free of positive electrode material after initial charge of the energy storage device; or the separator comprises alkali A continuous phase of a metal ion conductor and a continuous phase of a ceramic oxygen ion conductor.

According to another embodiment of the present invention, an energy storage device includes a plurality of cathode materials. Among other functions, the choice of cathode materials and their potential when chemically active, the ratio of cathode materials, the relative position of cathode materials to each other in the energy storage device, and the method of operation of the energy storage device can also indicate the energy storage capacity. The state of charge (SOC) of the device. The other functions may include pulsed peak charging, pulsed peak discharging, overcharge protection, overdischarge protection, increased power and/or increased energy density.

In order to realize the state of charge indication, the first positive electrode material can be most active metals, and the second positive electrode material can be paired with the first positive electrode material. The second positive electrode material may have a charge/discharge voltage that is significantly different from that of the active metal of the first positive electrode material. In alternative embodiments, the second cathode material may differ from the first cathode material by having a lower activation voltage or a higher activation voltage, or in some cases both a higher and a lower activation voltage. For example, in the case of using a copper-based first positive electrode material with chlorine as a halogen, a zinc-based second positive electrode material may be used. Copper is active at 2.6 volts and zinc is active at 2.2 volts. In this case, zinc can act as an end of discharge indicator such that with all the CuCl reduced to copper, the operating cathode voltage ( OCV) from 2.6 volts down to 2.2 volts.

In some embodiments, the following conditions exist: if the first positive electrode material or the second positive electrode material is nickel, the other positive electrode material is not iron, arsenic, or tin; if the first positive electrode material or the second positive electrode material is copper, then Another positive electrode material is other than arsenic or tin.

To achieve a state of charge indication, the amount of the second positive electrode material may be relatively small compared to the first positive electrode material. A ratio of the first positive electrode material to the second positive electrode material may be less than about 100:1. In one embodiment, the ratio may be from about 100:1 to about 75:1, from about 75:1 to about 50:1, from about 50:1 to about 25:1, from about 25:1 to about 15:1 1, from about 15:1 to about 5:1, or from about 5:1 to greater than about 1:1.

The combination of the first cathode material and the second cathode material can increase the energy density of the energy storage device, and can provide over-discharge protection relative to a single cathode material system. To achieve overdischarge protection, the second cathode material can be selected to have an activation voltage lower than that of the first cathode material but higher than that of the supporting electrolyte (eg, aluminum trichloride). Thus, unlike the case where all Cu is used up in a copper-only system, causing _AlCl3 to deposit as Al during continuous operation or at too low a voltage, Zn in a Cu/Zn system can precede the trichloride Aluminum reacts.

In one embodiment, the first positive electrode material is zinc and the second positive electrode material is copper. In this case, Cu is the SOC indicator, which indicates when all the zinc is oxidized to _ZnCl2 , at which point the positive operating voltage increases from 2.24 volts to 2.6 volts when Cu first begins to oxidize to CuCl. Additionally, copper provides overcharge protection. That is, copper will be oxidized rather than the supporting electrolyte (eg _AlCl3 ) being oxidized to _Cl2 .

In one embodiment, two or more cathode materials are mixed together. In another embodiment, the first positive electrode material is coated on top of the second positive electrode material. Thus, the second positive electrode material is not physically exposed or electrochemically available until the first positive electrode material is removed or electrochemically converted. This coating method can be applied to the case where an active metal (such as Zn and Cu) soluble in the positive electrode melt is the first positive electrode material, and a metal insoluble in the positive electrode melt (such as Ni) is the second positive electrode material.

Pulse charge and pulse discharge characteristics can be shown in a similar fashion. To achieve pulsed charge/discharge, a second cathode material may be added to provide faster or more active electrical energy intake and output relative to the first cathode material. The amount of second cathode material can be tailored to the specific requirements of the end use, as the type, location and amount of second cathode material can be based on the expected pulse volume. For example, in a plug-in hybrid vehicle (PHEV), 11 kilowatt-hours (kWh) of energy may be required at a low rate of discharge (e.g., 10 kW per hour), whereas a transient pulse of 3 to 10 seconds may 40kW to 50kW is required. In a dual cathode material system, the second cathode material can be charged or discharged at a higher current than the first cathode material. The voltage at which the material is active can be selected, and the voltage can be selected relative to the breakdown voltage of the electrolyte.

For example, in conjunction with the Cu/Zn example above, for a constant resistance of 0.005 ohms in the positive electrode and a cut-off voltage of 3.4 volts before electrolyte breakdown, copper can deliver 544 watts of power (3.4-2.6/0.005) at a voltage of 3.4 volts and Operating at 160 amps, Zinc can operate at 816 watts (3.4-2.2/0.005) at 3.4 volts and 240 amps to provide a relatively high pulse charge capability compared to copper alone . Zn can also provide pulse discharge capability by controlling the standard discharge potential of Cu cathode. With the same battery resistance, copper can be discharged at a power of 176 watts (2.6-2.2/0.005) at a voltage greater than 2.2 volts and a current greater than 80 amps. In a comparative example of a conventional electrochemical cell, this discharge mode allowed the cell to discharge in about 32 minutes—referred to as the 2C rate.

In one embodiment, to achieve pulsed discharge at higher currents, the cell voltage can be as low as 1.8 volts so that the first and second positive electrode materials can be discharged simultaneously rather than sequentially. This functionality is required in batteries where the resistance increases with state of charge as the reaction front of the cathode material moves deeper into the cathode and away from the separator. Relative to a standard battery, the resistance increases from 0.005 ohms to 0.025 ohms, and in this embodiment the power from the first positive electrode material (eg, copper as described above) drops from 176 watts to about 57.6 watts as the state of charge increases. The battery voltage may remain above 2.2 volts so that a second positive electrode material (such as the aforementioned zinc) located near the separator is still available at a lower resistance of 0.005 ohms, allowing discharge at a power pulse of 144 watts.

Separating the first cathode material from the second cathode material, rather than selecting by voltage, may be a suitable method for use with embodiments of the present invention. For example, in an elongated tube having a top end and a bottom end, a first positive electrode material can be placed at the top end and a second positive electrode material can be placed at the bottom end. The plate preventing the mixing of the positive electrode materials during use may separate the first positive electrode material from the second positive electrode material. Two current collectors, one in each active cathode material, electrically control which cathode material is charged and discharged.

Alternatively, the positive electrode material can be radially graded. The radial gradient can be formed by placing the first positive electrode material in a layer closer to the surface of the separator and the second positive electrode material in the center of the positive electrode compartment closer to the axis. The concentration of the first positive electrode material relative to the second positive electrode material varies with distance from the separator surface, or with distance from the axis (moving radially in the opposite direction). In one embodiment, the first positive electrode material is a metal with a higher activation voltage, such as zinc; the second positive electrode material is a metal with a lower activation voltage, such as nickel. Since at least a portion of the second positive electrode material is available at any state of charge, this concentration gradient arrangement allows for a maximum power pulse at any point in the cycle.

Another feature of bipositive electrodes may include alloy potential. Alloy oxidation products may be more conductive, more soluble, and have better kinetic properties than any single cathode material. For example, in Ni-Zn or Cu-Zn, the alloying of the two metals during the reduction of the chloride to the metal can form an alloy with relatively improved charging performance.

Non-limiting examples of contemplated cathode material pairings may include:

Ni and Cu:

Cu/CuCl can provide SOC indicators

Cu/CuCl and CuCl/ _CuCl2 for overcharge protection

CuCl/ _CuCl2 can provide pulse charging

Ni and Zn, Sn:

Zn and Sn can provide SOC indicators near the end of discharge

Zn, Sn can provide overcharge protection

Zn, Sn can provide pulse discharge (if the normal discharge remains greater than 2.2 volts)

Zn, Sn can provide pulse charging

Zn can be added in the form of metal, ZnCl ₂ , ZnS dissolved in the melt

Sn can be added in the form of metal or salt

Ni and W, Mo:

W, Mo can provide SOC indicators

Cu and W, Mo:

W, Mo can provide SOC indicators

Cu and Zn, Sn:

The role of Zn, Sn is the same as in the case of Ni above

Zn and Cu, Ni, Sn:

Ni and Cu can provide SOC indicators, overcharge protection, pulse discharge

Unless otherwise noted, the positive electrode material may be disposed within the second compartment. For the partition of the energy storage device, the second compartment may be arranged within the first compartment and may be elongated to define an axis. Thus, the first compartment may be arranged coaxially around the axis. Furthermore, with further reference to the separator, the separator may have a circular, triangular, square, cross or star-shaped cross-sectional profile perpendicular to the axis. Alternatively, the partition may be substantially planar. Planar (or slightly arched) structures can be used for prismatic or button cell configurations with arched or dimpled separators. Similarly, the partitions may be flat or corrugated. The separator material will be further described below.

The housing can be sized and shaped to have a square, polygonal or circular cross-sectional profile; and the housing can have an aspect ratio greater than about 1:10. In one embodiment, the aspect ratio is from about 1:10 to about 1:5, from about 1:5 to about 1:1, from about 1:1 to about 5:1, from about 5:1 to about 10:1 , about 10:1 to about 15:1. The housing can be made of metal, ceramic or composite; the metal can be selected from nickel or steel and the ceramic can be a metal oxide.

Optionally, one or more spacer structures may be provided at opposite ends of the separator. The spacer structure supports the bulkhead inside the enclosure. The spacer structure protects the separator from vibrations caused by battery movement during use, thereby reducing or eliminating movement of the separator relative to the housing. If present, the spacer structure can act as a current collector for the housing. If the potential of the molten anode rises and falls during charge and discharge, it may be advantageous to use a gasket structure as a current collector. The spacer structure can provide a narrow gap adjacent to the separator to facilitate wicking of the thin layer of molten negative electrode material to the surface of the separator. The wicking effect may be independent of the state of charge of the battery and independent of the head height of the negative electrode material.

In one embodiment, the first compartment can contain a negative electrode material, such as sodium, that can act as a negative electrode. Other suitable negative electrode materials may include one or both of lithium and potassium, and may be used in place of or in combination with sodium. The negative electrode material can be melted during use. The first sub-chamber can receive and store negative electrode material storage. Additives suitable for negative electrode materials may include metal oxygen scavengers. Suitable metal oxygen scavengers may include one or more of manganese, vanadium, zirconium, aluminum or titanium. Other useful additives may include materials that increase the wettability of the separator surface by the molten negative electrode material. In addition, some additives can enhance the contact or wettability of the separator with respect to the current collector to ensure substantially uniform current flow across the separator.

The second compartment can accommodate positive electrode material, and the positive electrode material can be, for example, one or more of the first positive electrode material, the second positive electrode material or the third positive electrode material. The first positive electrode material may exist in a simple form or in a salt form according to a state of charge. That is, the first positive electrode material exists in elemental form and/or in salt form, and the ratio of the weight percent of the first positive electrode material in elemental form to the weight percent of the first positive electrode material in salt form may be based on the state of charge. Materials suitable for use as the first positive electrode material may include aluminum, nickel, zinc, copper, chromium, tin, arsenic, tungsten, molybdenum, and iron. In one embodiment, the first positive electrode material consists essentially of only one of zinc, copper, or chromium. In one embodiment, the first positive electrode material consists essentially of only two of nickel, zinc, copper, chromium, or iron. In one embodiment, the first positive electrode material consists essentially of only three of aluminum, nickel, zinc, copper, chromium, tin, arsenic, tungsten, molybdenum, and iron. The second cathode material and the third cathode material are different from the first cathode material. The first cathode material, the second cathode material, and the third cathode material may be intermixed, may be adjacent, or may be spatially and/or electrically displaced from each other.

If present, the second positive electrode material is different from the first positive electrode material and may include aluminum, nickel, zinc, copper, chromium, and iron. Other suitable second positive electrode materials may include tin and/or arsenic. Other suitable second positive electrode materials may include tungsten, titanium, niobium, molybdenum, tantalum, and vanadium. The first positive electrode material may be present in a ratio of less than about 100:1 relative to the second metal. In one embodiment, the first positive electrode material may be present in the following ratio ranges relative to the added metal: about 100:1 to about 50:1, about 50:1 to about 1:1, about 1:1 to about 1 :50, about 1:50 to about 1:95.

The first positive electrode material may be self-supporting or liquid/molten, and in one embodiment the positive electrode material is disposed on a support structure. Alternatively, a second cathode material having a different activation voltage can support the cathode material. The support structure can be foam, mesh, fabric, felt, or heavily filled with particles, fibers, whiskers. Suitable support structures may be formed from carbon. A suitable carbon foam is reticulated glassy carbon.

The first positive electrode material can be fixed on the outer surface of the support structure. The support structure can have a large surface area. The first positive electrode material on the support structure can be adjacent to and extend from the first surface of the separator. The support structure may extend from the first surface to a thickness greater than about 0.01 mm. In one embodiment, the thickness is about 0.01 mm to about 0.1 mm, about 0.1 mm to about 1 mm, about 1 mm to about 5 mm, about 5 mm to about 10 mm, about 10 mm to about 15 mm , about 15 mm to about 20 mm. For larger capacity electrochemical cells, the thickness may be greater than 20 mm.

Homogenization of the liquid can be avoided by placing the first positive electrode material on the surface of the support structure, rather than in the second compartment as a liquid melt. That is, placement on a support enables the positioning of specific materials within the electrochemical cell. For example, the concentration of the first positive electrode material in elemental form may be different from a position closer to the separator to a position farther from the separator. Similar to an onion, there may be multiple layers of the first positive electrode material in different concentrations or amounts depending on where it is located within the electrochemical cell. Similarly, gradients can be created to account for, for example, an increase in electrical resistance, or to provide more constant availability of reactants as the reaction front area changes as reactants are used and advances away from the separator surface into the cell body. As used herein, a gradient can include a stepwise change in concentration and thus be configured to function as a state-of-charge indicator.

Materials suitable for the negative electrode material to provide transport ions are group I metals, such as sodium. The salt of the negative electrode material may be a metal halide. Suitable halides may include chlorides. Alternatively, the halide may include bromide, iodide or fluoride. In one embodiment, the halide may include chloride, and one or more additional halides. Suitable additional halides may include iodide or fluoride. In one embodiment, the additional halide is sodium iodide or sodium fluoride. The amount of additional halide may be greater than about 0.1 weight percent. In one embodiment, the amount ranges from about 0.1 weight percent to about 0.5 weight percent, from about 0.5 weight percent to about 1 weight percent, from about 1 weight percent to about 5 weight percent, from about 5 weight percent to about 10 % by weight.

In one embodiment, the electrolyte may include a salt of a first metal, a salt of a second metal, and a salt of a third metal to form a ternary melt at an operating temperature high enough to melt the salts. The ternary melt can be, for example, _MCl2 :NaCl: _AlCl3 , where M represents the first metal. Metals suitable for use as the first metal "M" include transition metals.

A suitable ratio of _MCl2 :NaCl: _AlCl3 is such that the _MCl2 content is up to about 20 weight percent. The amount of _AlCl3 in the ternary melt can be greater than about 10 weight percent based on the total weight. In one embodiment, the amount of _AlCl3 in the ternary melt is about 10 weight percent to about 20 weight percent, about 20 weight percent to about 30 weight percent, about 30 weight percent to about 40 weight percent, about 40 weight percent % to about 50 weight percent, about 50 weight percent to about 60 weight percent, or about 60 weight percent to about 70 weight percent. In one embodiment, the weight of _AlCl3 is greater than the weight of NaCl. In another embodiment, the weight of NaCl is greater than the weight of _AlCl3 .

In one embodiment, the plurality of electrolyte salts includes a mixture of two metal salts to form a binary melt at the operating temperature. Suitable binary melts may include _MCl2 :NaCl or _MCl2 : _AlCl3 . In one embodiment, the binary melt consists essentially of _MCl2 : _AlCl3 . A suitable amount of _MCl2 may be greater than 10 weight percent. In one embodiment, the amount of _MCl is from about 10 weight percent to about 20 weight percent, from about 20 weight percent to about 30 weight percent, from about 30 weight percent to about 40 weight percent, from about 40 weight percent to about 50 weight percent Percentage, about 50 weight percent to about 60 weight percent, about 60 weight percent to about 70 weight percent, about 70 weight percent to about 80 weight percent, or about 80 weight percent to about 90 weight percent.

Additives containing sulfur or phosphorus can be provided in the positive electrode material. The presence of sulfur or phosphorus in the cathode inhibits salt recrystallization and grain growth. For example, elemental sulfur, sodium sulfide, or triphenyl sulfide may be disposed in the positive electrode.

The suitable working temperature of the energy storage device can be greater than 150°C and can be selected according to the composition and performance requirements. In one embodiment, the working temperature is from about 150°C to about 200°C, from about 200°C to about 250°C, from about 250°C to about 300°C, from about 300°C to about 350°C, from about 350°C to about 400°C, From about 400°C to about 450°C, from about 450°C to about 500°C, or from about 550°C to about 600°C.

The separator is a sodium ion conductor solid electrode that conducts sodium ions in use. Suitable separators may include composites of alumina and metal (ceramic) oxides. Aluminum can be β-alumina, β”-alumina, or a mixture thereof, and is rapidly conductive to sodium ions. _The compositional range of β-alumina is defined by the _Na2O - _Al2O3 phase diagram. β-alumina Aluminum has _a hexagonal crystal structure _{and contains about} 1 mole Na ₂ O to about 9 moles Al ₂ O ₃ . 5 moles of Al ₂ O ₃ , and has an orthorhombic structure. In one embodiment, one portion of the separator is alpha-alumina and the other portion of the separator is beta-alumina. Alpha-alumina may be easier to join (eg, pressure join) than beta-alumina and facilitate sealing and/or fabrication of energy storage devices.

The separator can be stabilized by adding small amounts (without limitation) of lithium oxide, magnesium oxide, zinc oxide, yttrium oxide, or similar oxides. These stabilizers may be used alone or in combination with these stabilizers themselves or other materials. BASE may include one or more dopants. Suitable dopants may include oxides of transition metals selected from iron, nickel, copper, chromium, manganese, cobalt or molybdenum. The separator, sometimes called β"-alumina separator electrolyte (BASE), has a higher sodium ion conductivity than β-alumina. One form of β"-alumina separator electrolyte conducts sodium ions at 300°C The rate is about 0.2 ohm ^-1 cm ^-1 to about 0.4 ohm ^-1 cm ^-1 .

The amount of stabilizer for β"-alumina may be greater than 0.5 weight percent. In one embodiment, the amount is from about 0.5 weight percent to about 1 weight percent, based on the total weight of the β"-alumina material, about 1 weight percent % to about 2 weight percent, about 2 weight percent to about 3 weight percent, about 3 weight percent to about 4 weight percent, about 4 weight percent to about 5 weight percent, about 5 weight percent to about 10 weight percent, about 10 weight percent % to about 15 weight percent, about 15 weight percent to about 20 weight percent, or greater than about 20 weight percent.

The metal oxide may be any suitable alkali metal oxide, alkaline earth metal oxide, transition metal oxide or rare earth metal oxide. In one embodiment, the metal oxide may be a doped metal oxide. In another embodiment, the metal oxide comprises a mixed metal oxide. Suitable metal oxides may include zirconia, yttrium oxide, hafnium oxide, cerium oxide, and thorium oxide. Other suitable mixed metal oxides may include yttria stabilized zirconia, rare earth oxide doped zirconia, scandia doped zirconia, rare earth oxide doped ceria, alkaline earth oxide doped cerium oxide or stabilized hafnium oxide. In one embodiment, the metal oxide includes zirconia. In one embodiment the metal oxide may comprise yttria stabilized zirconia (YSZ). A suitable amount of yttrium oxide in YSZ may be greater than about 1 weight percent, or may be less than about 10 weight percent. In one embodiment, the amount of yttrium oxide can be from about 1 weight percent to about 2 weight percent, from 2 weight percent to about 3 weight percent, from 3 weight percent to about 4 weight percent, from 4 weight percent to about 5 weight percent, 5 weight percent to about 6 weight percent, 6 weight percent to about 7 weight percent, 7 weight percent to about 8 weight percent, 8 weight percent to about 9 weight percent, or greater than about 9 weight percent. As will be discussed further on grains later, the presence of metal oxides can reduce the chance of forming grains with a relatively increased grain size.

Suitable preparation methods include sintering, optionally followed by forging of the sinter, and crystal growth using, for example, flux methods. In one embodiment, additives can be used to affect the resulting ceramic monolith. Zirconium, YSZ or selenium can be used as additives to the composite separator material during the formation process. For polycrystalline or semi-polycrystalline materials, the control of grain size, grain boundaries, and chemical properties at grain boundaries can be achieved by selecting raw materials, the order and amount of addition of materials, and the type and method of formation.

Alternatively, preparation of a composite of alpha-alumina and an oxygen ion conductor and subsequent exposure of the composite to a vapor, fume or plasma containing an alkali metal oxide can make a suitable separator. Suitable oxygen ion conductors may include one of the metal oxides and stabilized metal oxides described above. Suitable alkali metal oxides may include sodium oxide. The vapor, fume or plasma may include one or more of the aforementioned stabilizers to inhibit the conversion of β"-alumina to β-alumina. Alternatively or additionally, a stabilizer may be added to the complex .

A suitable separator formed from a ceramic composite can first be formed into a green body formed from alpha-alumina and an oxygen ion conductor. The green body can be processed by pressing, extrusion, slip casting, injection molding, tape casting, etc., followed by sintering or hot pressing. The physical properties of the final article depend largely on the physical properties of the initial ceramic composite and the processing of the green body.

The amount of alpha-alumina and oxygen ion conductor present in the green body is sufficient to form a continuous matrix of alpha-alumina phase and oxygen ion conductor phase. Two continuous and interpenetrating networks are thus provided. The amount of alpha-alumina may be from about 90 vol.% to about 70 vol.% and the amount of the oxygen ion conductor may be from about 10 vol.% to about 30 vol.%. As previously described, the green body may be exposed to an appropriate ionic species (as the metal oxide) in the form of an alkali metal oxide vapor, fume, or plasma at elevated temperatures greater than about 800°C and less than about 1700°C (atmospheric pressure) . The temperature may be based on the evaporation loss of the alkali metal oxide.

The vapor, fume or plasma may include an alkali metal oxide and (if desired in β" form) optional stabilizing ions. The green body may be placed in the precursor powder of the vapor, fume or plasma and when heated When reaching the reaction temperature, the precursor generates vapor, smoke or plasma. During the conversion process, oxygen ions are transported through the oxygen ion conductor, while sodium ions are transported through the green body. Transport channels are provided for both ions to increase reaction kinetics. The reaction kinetics can be based on the formation of alkali-β or β"-alumina at the reaction front; the reaction front is what separates the α-alumina (with the oxygen ion conductor) from the formed alkali-β or β"-alumina (with Oxygen ion conductors). By controlling the activity of sodium ions when vapor, fume, or plasma is formed (and not sintered), little or no liquid phase is formed. And little or no formation or deposition occurs in the interstitial spaces Or no formation or deposition of eg sodium aluminate.Smaller grain size may also reduce the volume of interstitial space or eliminate interstitial space.

Furthermore, regarding the crystal grains of the separator, the separator has a microstructure including a plurality of crystal grains. In one embodiment, as described herein, the plurality of grains may comprise some grains of a stabilizer, such as zirconia, in an interpenetrating phase or matrix. The stabilizer grains may be greater than about 10% relative to the grains of other materials in the composite separator. In one embodiment, the stabilizer grains in the composite separator may comprise from about 10% to about 20%, from about 20% to about 30%, from about 30% to about 40%, or from about 40% to about 50%. %.

In another embodiment, the composite separator may have a graded concentration of stabilizer grains through its thickness. Ramping the concentration of a given species changes the cross-sectional difference. Unless otherwise indicated, ramping includes both concentration changes with a smooth slope as well as multi-step concentration changes. The concentration of the stabilizer grains can be graded in the axial direction, but in at least one embodiment the grains can extend a certain distance and then be interrupted by the spacer having a boundary on the other side of the boundary with α- alumina.

Furthermore, the microstructure of the composite separator may not change or deteriorate appreciably during use. The grains of the composite may have grain boundaries that define interstitial spaces that are free of ternary melt or binary melt. In one embodiment, the plurality of grains may have grain boundaries defining interstitial spaces that are free of ternary or binary melt. The interstitial spaces provide relatively high sodium ion conductivity.

The separator may be a ceramic composite of an oxygen ion conductor and β- or β"-alumina. In one embodiment, the BASE separator is a composite of β"-alumina and zirconia. Zirconia has good strength properties and good chemical stability. Thus, the resulting separator can have higher mechanical strength, be more durable, and be more reliable. Due to the resulting chemical stability and strength, composite BASE separators can improve the reliability of electrochemical cells and allow the use of thinner walled separators with lower ionic resistance while maintaining appropriate resistance. The thinner walls of the composite separator provide relatively high strength while maintaining suitably high ionic conductivity.

In one embodiment the partition may be a tubular container having at least one wall. The tube wall may have a certain thickness; and ion conductivity and impedance across the tube wall may depend in part on thickness. A suitable thickness may be less than 5mm. In one embodiment, the thickness is from about 5 mm to about 4 mm, from about 4 mm to about 3 mm, from about 3 mm to about 2 mm, from about 2 mm to about 1.5 mm, from about 1.5 mm to about 1.25 mm , about 1.25 mm to about 1.1 mm, about 1.1 mm to about 1 mm, about 1 mm to about 0.75 mm, about 0.75 mm to about 0.6 mm, about 0.6 mm to about 0.5 mm, about 0.5 mm to about 0.4 mm, about 0.4 mm to about 0.3 mm, or less than about 0.3 mm.

In one embodiment, a cation facilitator material may be provided on at least one surface of the separator. Cationic promoter materials may include, for example, selenium. At least one surface of the separator has a surface roughness RMS greater than about 10 nanometers. In one embodiment, the surface roughness RMS is from about 10 nanometers to about 20 nanometers, from about 20 nanometers to about 30 nanometers, from about 30 nanometers to about 40 nanometers, from about 40 nanometers to about 50 nanometers, from about 50 nanometers to about 60 nanometers Nanometer, about 60 nanometers to about 70 nanometers, about 70 nanometers to about 80 nanometers, about 80 nanometers to about 90 nanometers, about 90 nanometers to about 100 nanometers.

The partition can be sealed with the inner surface of the housing by means of a sealing structure. The sealed structure may contain a glassy component. The sealing structure is operable to maintain a seal between the contents and the environment at temperatures greater than about 100°C. In one embodiment, the working temperature is from about 100°C to about 200°C, from about 200°C to about 300°C, from about 300°C to about 400°C, from about 400°C to about 500°C, from about 500°C to about 600°C. The separator may not be corroded or pitted in the presence of the halogen and the negative electrode material.

Suitable vitreous components may include, but are not limited to, phosphates, silicates, borates, germanates, vanadates, zirconates, arsenates, and variations thereof such as borosilicates, aluminosilicates salt, calcium silicate, binary alkali metal silicate, alkali metal borate, or a combination of two or more thereof. Alternatively, the ends of the separator may comprise alpha-alumina. The alpha-alumina can be directly engaged with the lid closing the second compartment. Suitable bonding methods may include thermocompression bonding, diffusion bonding, or thin film metallization, each of which may be used in conjunction with welding or brazing techniques.

The article can have multiple current collectors, including negative and positive current collectors. The negative electrode current collector is in electrical communication with the first compartment, and the positive electrode current collector is in electrical communication with the contents of the second compartment. Materials suitable for the negative electrode current collector may include Ti, Ni, Cu, Fe, or a combination of two or more thereof. Other suitable materials for the negative electrode current collector may include steel or stainless steel. Still other suitable materials for negative electrode current collectors may include carbon. The current collector can be subjected to plating or cladding. The positive electrode current collector may be a wire, blade or grid made of Pt, Pd, Au, Ni, Cu, C or Ti. The plurality of current collectors may have a thickness greater than 1 millimeter (mm). In one embodiment, the thickness is from about 1 mm to about 10 mm, from about 10 mm to about 20 mm, from about 20 mm to about 30 mm, from about 30 mm to about 40 mm, or from about 40 mm to about 50 mm. mm. The coating on the current collector, if present, can be applied to the current collector to a thickness greater than 1 μm. In one embodiment, the coating has a thickness of about 1 micrometer (μm) to about 10 μm, about 10 μm to about 20 μm, about 20 μm to about 30 μm, about 30 μm to about 40 μm, or about 40 μm to about 50 μm.

The operation of the article and the function of the electrochemical cell are described below in connection with the illustrated embodiments. Embodiments of the present invention have been described with reference to the drawings, but the present invention is not limited thereto.

Figure 1 shows an article 100 according to an embodiment. Article 100 can be used as an electrochemical cell for generating energy. The device includes a housing 102 . The housing includes a bulkhead 104 having an outer surface 106 and an inner surface 108 . The outer surface defines a first compartment 110 and the inner surface defines a second compartment 112 . The first compartment is the negative electrode including sodium and the second compartment is the positive electrode including various salts. The first sub-chamber is in electrical communication with the second sub-chamber via the partition. The first and second compartments also include a negative current collector 114 and a positive current collector 116 to collect the electrical current generated by the electrochemical cell.

The article can be an electrochemical cell. Electrochemical cells can be assembled in a discharged state. An electrochemical cell is charged by applying a voltage between its negative and positive electrodes and reversing the electrochemical reaction. During charging, sodium chloride in the positive electrode decomposes due to the applied potential to form sodium ions and chloride ions. The sodium ions conduct through the separator under the action of the applied potential and combine with the electrons from the external circuit to form a sodium electrode, and the chloride ions react with the transition metal in the first material to form metal chloride and supply electrons to the external circuit. During the discharge process, sodium ions conduct reversely through the separator, the reaction proceeds in reverse, and electrons are generated. The battery reacts as follows:

2NaCl+ positive electrode material → (positive electrode material) Cl ₂ + 2Na

Referring to FIG. 2 , a number of energy storage devices ( FIGS. 2A through 2J ) are shown to illustrate various design options. In FIGS. 2A to 2J , the same symbols are used to designate the same parts (the same means the same function). Thus, assembly 200 includes an energy storage device having an elongated housing 210 defining an axis 220 . The inner surface of the housing wall defines a volume. The volume includes a negative electrode 230 and a positive electrode 240 physically separated from each other by a separator 250 and a core 260 . The core is disposed on the outwardly facing surface of the separator and allows the liquid negative electrode material to flow on the surface of the separator to be transported through the separator. Since the partition is a closed space that is capped at each end, there are effectively two compartments within the volume - an inner compartment and an outer compartment.

Some designs are self-explanatory; others are explained in more detail. Figure 2C includes a plurality of separators, where each separator can have a core and a current collector. For Figures 2D-2E, there is a phenomenon that as the first material is consumed during use, the front surface area of the unused material does not change appreciably. In contrast, in Fig. 2A, for example, the reaction front surface area of the first material becomes smaller as the first material (similar to a cylinder) is used.

Figure 2I differs from the other designs in that the negative electrode 270 is inside the separator 274 and the positive electrode 272 is outside the separator 274, which has a core 276 on its inner surface. Similar to the embodiment shown in Figure 2C, with multiple spacers. The housing 290 can be made of materials resistant to high temperature and chemical corrosion.

For any of the foregoing designs, the first positive electrode material can be deposited on the foam support. However, in Figure 2I, the support material can also support the separator. The support reduces or eliminates damage caused by thermal cycling, pressure differentials, and vibration.

Referring to Figure 2J, a separator is provided having two "legs" that are oval in cross-section. Due to the perspective view, the overall connection structure on the "legs" during operation is not shown. The overall structure may look like a pair of pants. For cases with an even number of partitions, the axis is non-coaxial with at least one partition.

Multiple electrochemical cells can be arranged in an energy storage system. Multiple cells can be arranged in series or in parallel to form a stack. The power and energy rating of the stack may depend on factors such as stack size or the number of cells in the stack. Other factors may be based on the specific criteria of the end application.

Various embodiments of energy storage devices can store energy from about 0.1 kilowatt hours (kWh) to about 100 kWh. One embodiment of the energy storage device has an energy/weight ratio greater than 100 Wh/kg, and/or an energy/volume ratio greater than 160 Wh/liter. Another embodiment of the energy storage device has a specific power rating greater than 150 watts per kilogram.

Suitable energy storage devices may have an applied specific power/energy ratio of less than 10:1. In one embodiment, the specific power/energy ratio is from about 1:1 to about 2:1, from about 2:1 to about 4:1, from about 4:1 to about 6:1, from about 6:1 to about 8 :1, or about 8:1 to about 10:1. In other embodiments, the specific power/energy ratio is about 1:1 to about 1:2, about 1:2 to about 1:4, about 1:4 to about 1:6, about 1:6 to about 1:6 8, or about 1:8 to about 1:10.

In one embodiment of the energy storage system, the controller communicates with the plurality of batteries. The controller may distribute the electrical load to selected cells in the battery pack in response to feedback signals indicative of the status of the individual cells in the battery pack. The controller is operable to implement a rewarm method wherein a series of heating elements are sequentially activated to melt the condensed portion of the energy storage device. In another embodiment, the controller can distribute the electrical load to selected cathode materials located at defined locations within each cell.

A suitable controller may be a proportional-integral-derivative controller (PID controller). The controller measures a value obtained from a process or other equipment and compares that value to a reference setpoint. The difference (or "error" signal) can be used to adjust some process input value to bring the process measurement back to its desired setpoint.

A thermal management device (if present) maintains the temperature of the energy storage device. The thermal management device may heat the energy storage device if it is too cold, and cool the energy storage device if it is too hot. The thermal management system includes a thaw profile that keeps the first and second compartments at a minimum heat level to prevent freezing of battery reactants.

Another embodiment of the present invention provides an energy management system comprising a second energy storage device different from said energy storage device. Such a dual energy storage device system can address the power to energy ratio problem where the first energy storage device can be optimized for efficient energy storage and the second energy storage device can be optimized for power delivery. The control system can obtain energy from any energy storage device as needed and charge any energy storage device that needs to be charged.

Secondary energy storage devices suitable for power pieces include primary batteries, secondary batteries, fuel cells, or supercapacitors. Suitable secondary batteries may be lithium batteries, lithium ion batteries, lithium polymer batteries or nickel metal hydride batteries.

Example

The following examples are intended to illustrate the methods and embodiments of the invention only and should not be construed as limitations on the claims. Unless otherwise noted, all ingredients were commercially available from common chemical suppliers such as AlphaAesar, Inc. (Ward Hill, Massachusetts), Spectrum Chemical Mfg. Corp. (Gardena, California).

The preparation of embodiment 1 electrode

Several metal-coated carbon foam electrodes measuring 1.25 cm x 1.25 cm x 2 mm (thickness) were prepared by electroplating the carbon foam with layers of copper or nickel as appropriate. Carbon foams are available from ERG Material and Aerospace Corp. (Oakland, California). The foam electrode has a carbon-containing reticulated glassy carbon (RVC) foam skeleton. The carbon foam has a pore density of 100 pores per inch (PPI) and an average pore size of about 100 microns.

Electroplating may suitably be performed in an aqueous solution of copper or nickel. The coating coats the carbon foam to form the prepared metal-coated porous electrode substrate. Some of the nickel-plated porous electrodes were further dipped into the zinc solution to coat the metallic zinc on top of the nickel layer.

The fabricated metal-coated carbon foam electrodes were analyzed and characterized. When observed under an optical microscope at a magnification of 200X, a smooth and glossy surface of the copper-coated electrode substrate was presented. Copper has an effective density of about 0.01 g/cm ³ . When observed under an optical microscope at a magnification of 200X, the surface of the nickel-plated electrode substrate is smooth and shiny. Nickel has an effective density of about 0.01 g/cm ³ . When viewed under an optical microscope at a magnification of 200X, the surface of the zinc-nickel electrode substrate appears dull and grainy. Zinc has an effective density of about 0.49 g/cm ³ . The metal zinc plated on the nickel electrode was about 0.2 microns thick, and the working electrode had a rectangular section thickness of 1.5 cm and a depth of 2 mm.

The preparation of embodiment 2 separator

Multiple separators were prepared. The plurality of separators includes two sets of separators, each set of separators having a different type of stabilizer phase. Two different types of zirconia _phases include (i) 8 _mol .% _Y2O3 stabilized cubic zirconia (8YSZ) and (ii) 4.5 mol.% _Y2O3 stabilized tetragonal and cubic zirconia ( 4.5YSZ).

Separators formed using stabilized zirconia were fabricated into three types of discs. The three types of wafers include two types belonging to type (i) and one type belonging to type (ii). The three samples were characterized as having the following compositions: (a) 50 vol.% α-alumina + 50 vol.% 8YSZ; (b) 70 vol.% α-alumina + 30 vol.% 8YSZ; and (c) 50 vol.% .% α-alumina + 50vol.% 4.5YSZ. Disc-shaped samples of composition (a), (b) and (c) with a thickness of 2.5 millimeters (mm)) were prepared by using the desired powder mixture, by molding, followed by isostatic pressing, and then at 1600 °C Sintered in air. The sintered disc is placed in the powder mixture. The composition of the powder mixture was 8.85 wt.% Na ₂ O, 0.75 wt.% Li ₂ O and 90.45 wt.% Al ₂ O ₃ . The discs in the powder were calcined at 1250°C for 2 hours to form sodium-β"-alumina and act as a source of sodium-lithium oxide during the reaction. The samples were incubated at 1450°C for 2 hours to about 16 hours. The sample was cut and the thickness of the sodium-β"-alumina formed was measured.

One sample with composition (a) was further heat-treated at 1450° C. for a longer time (32 hours) to ensure complete conversion of the sample to sodium-β-alumina. Conductivity (σ) was measured from about 200°C to about 500°C. The activation energy was measured to be about 15.7 kilojoules per mole (kJ/mol). Conductivity at 300° C. is 0.0455 Siemens per centimeter (S/cm) (resistivity 22 ohm-centimeter (Ωcm)). The sample has 50 vol.% zirconia. Furthermore, the grain size of sodium-β-alumina is several micrometers. The measured conductivity is consistent with known values for fine-grained Na-β-alumina.

Embodiment 3 Formation and testing of test battery

The configuration of the battery used for the test in Example 3 was basically the same as that shown in FIG. 1 . A cylindrical composite separator tube was prepared according to the process of Example 2 using composition (a). The dimensions of the cylinder are as follows: length 228 mm, inner diameter 36 mm, outer diameter 38 mm. The composite separator tube is insulated from an alpha alumina collar by means of glass. Place the assembly in a stainless steel tank. The tank measures approximately 38mm x 38mm x 230mm. The composite separator contained 50 grams (g) Cu, 22 grams NaCl, 25 grams _NaAlCl4 . In addition, 11 g of reticulated glassy carbon was added to the cathode to prevent the precipitation of CuCl between charge and discharge. An electric heater surrounds the battery. During operation, the battery is heated to an operating temperature of 300°C. Charge and discharge the battery at 4A and 12A currents. After several charge and discharge cycles, the battery is disconnected, cooled and tested. Microscopic examination of the spacer grains showed no infiltration of copper into the interstitial spaces.

The current collectors for the working and auxiliary electrodes were rectangular blades made of titanium and had the same cross-sectional shape and area as the foam-based electrodes. The blades were spot welded to 1-mm Ti wire. Sheets of nonwoven borosilicate glass fiber filter media (Whatman GF/C) were stacked to a thickness of 0.15 centimeter (cm). An additional glass filter medium was placed on the back of the Ti blade. A spring was made by bending a 1-mm long titanium wire into a W shape. Said springs press against the back of the titanium blades, thus slightly compressing the entire assembly. An additional glass dielectric on the back of the blade provides electrical insulation so that the spring does not create an electrical path between the two electrodes.

The connecting wires of the three electrodes were passed through a conical stopper fitted in the central neck of the flask. Utilize a dry glove box purged with _N2 , and finally connect the moisture-sensitive sodium electrode. The connecting wires were adjusted so that the foam electrodes were fully immersed in the molten salt. The sodium reference electrode is close to the working/auxiliary electrode assembly, but outside the working/auxiliary electrode assembly.

The external leads were connected to a computer interface galvanostat (PARSTAT 2272 from AMETEK Princeton Applied Research (Oak Ridge, TN)) and constant current data was measured. The working electrode was first oxidized at 100 milliamps (mA) for 3600 seconds, followed by reduction at 400 mA for 900 seconds. The open circuit potential was measured to be 2.077 volts versus Na. The charging voltage is 2.17 volts and the discharging voltage is 2.02 volts. When all the zinc in the Ni-plated foam was depleted, the open circuit voltage was 2.58 volts.

Embodiment 4 tests the formation of energy storage device

The energy storage device was formed using β"-alumina tubes and copper tubes. The β"-alumina tubes had an inner diameter of 6.5 mm, an outer diameter of 8.6 mm, and a total length of 68 mm. The copper tube was sized and shaped to accommodate the β"-alumina tube. The copper tube had an inner diameter of 12.7 mm. The β"-alumina tube was placed in the copper tube. In addition to the copper tube, 1.2 grams of sodium chloride and 3.4 grams of electrolyte AlCl ₃ : NaCl were placed in the space between the inner surface of the β"-alumina tube and the outer surface of the copper tube. Placed inside the β"-alumina tube 0.2 grams of sodium in contact with a nickel wire (as current collector) with a diameter of 1 mm.

The energy storage device body and nickel current collectors within the β"-alumina tubes were connected to a PAR barostat/galvanostat Model 2273. An electric heater surrounded the energy storage device. During testing, the heater (and subsequent energy storage device) heated to a working temperature of 300°C.

After an initial charge cycle at 0.025 A to achieve a total charge of 1360 coulombs, the energy storage device was charged and discharged 140 times at 0.5 A (61.8 mA/cm ² ). The charging capacity per cycle is 500 coulombs. The voltage between the battery terminals oscillates between about 2 volts and 3.2 volts when cycled. The polarization curve is shown in Fig.3. Discharge curves (300, 304, 308, 312) and charge curves (302, 306, 310, 314) are shown representing 10 cycles, 50 cycles, 90 cycles, 120 cycles, respectively. No increase in cell resistance was observed.

Embodiment 5 Tests the formation of energy storage device

Two energy storage devices were formed, each comprising commercially available cylindrical β"-alumina tubes. The tubes contained no stabilizer and each tube contained sodium aluminate present between the grains, And the size of the grain is large enough. Each tube has an inner diameter of 36mm, an outer diameter of 38mm, and a total length of 228mm. The nickel foil is thermocompressed with the α-alumina collar. The β”-alumina tube is wrapped with glass and foil coated α-alumina ferrules to form components. The assembly was placed in a square stainless steel enclosure with dimensions approximately 38mm x 38mm x 230mm. The assembly is welded to the housing to form a hermetic seal. The nickel foil and alpha-alumina collar define the opening in the assembly. Fill the positive electrode material and other materials into the β"-alumina tube through the opening. The β"-alumina tube is filled with 100 grams of copper, 44 grams of sodium chloride, 1 gram of aluminum and ₄₈ grams of NaAlCl form of electrolytes. A nickel rod was placed in the center of the β"-alumina tube and in contact with the negative material to act as a current collector. The opening was covered by a metal cap. The metal cap was welded on the collar to form a fully sealed Battery. The battery has a theoretical capacity of 20.18 amp-hours. An electric heater surrounds the energy storage device. Turning on the heater raises the temperature of the enclosure to an operating temperature of approximately 350°C. After the current charging cycle reaches a total charge capacity of 17.95 ampere-hours (64,620 coulombs), the energy storage device is charged and discharged at a current of 2 amps and 4 amps (equivalent to 6 amps and 12 amps of a fuel cell). The performance of the energy storage device is shown in FIG. 4 .

The voltages of the two energy storage devices are close to each other and remain stable during the discharge cycle. The capacity of the battery is temperature dependent: an equivalent 2 amp discharge at 300°C yields 2.25 amp-hours, and a 2 amp discharge at 380°C yields 8.75 amp-hours.

Figure 5 includes a comparison of the resistance of the test cell with the standard Na/ _NiCl2 cell during charging. As shown, the test cells had a relatively low resistance and a small rise in resistance with ampere-hours charged. After only a few cycles, each β"-alumina tube ruptured. Copper migrated at most about 1/3 of the distance through the β"-alumina tube wall.

Embodiment 6 Formation of energy storage device

An energy storage device was fabricated in the same manner as the energy storage device of Example 5, except that 11 grams of carbon was added to the positive electrode material. The added carbon prevents the precipitation of CuCl during the charge and discharge modes of operation. An electric heater surrounds the energy storage device. The heater is activated to heat the energy storage device to an operating temperature of about 300°C.

After an initial constant voltage charge cycle at 3 to 15 amps to a total charge of 10 amp-hours, the energy storage device was charged and discharged at 4 amps and 12 amps. The charging performance of the battery is approximately the same as that of the energy storage device in Example 4. The discharge voltage is also approximately the same. The difference from the energy storage device of Example 4 is that the amount of CuCl used during discharge is higher (85%) (the average value of the device of Example 4 is 50%). After only a few cycles, the separator tubes ruptured. Copper migrates up to about 1/3 the distance through the β"-alumina tube wall.

Embodiment 7 Tests the formation of energy storage device

An energy storage device was formed in the same manner as in Example 6, except that the β"-alumina tubes were different. The β"-alumina tubes in this example were prepared by a vapor phase impregnation process. Compared with the tubes used in Examples 5 and 6, the β"-alumina tube interstitial phase contains less sodium aluminate. The performance of the energy storage device of this example is similar to that of the energy storage device of Example 6. Similar. The difference is that no copper penetrates or migrates into the tube wall of the β"-alumina tube after use.

The embodiments described herein are examples of compositions, structures, systems and methods having elements corresponding to elements of the invention as claimed. This description enables those skilled in the art to implement and utilize embodiments having alternative elements that also correspond to elements of the invention as claimed. Therefore, the scope of the present invention includes compositions, structures, systems, and methods that are different from the expressions of the claims, and also includes other structures, systems, and methods that are not substantially different from the expressions of the claims. While only a few features and embodiments have been illustrated and described herein, various modifications and changes will occur to those skilled in the art. The appended claims cover all such improvements and changes.

Claims (74)

1. energy storage device comprises:

The positive electrode that comprises copper; And

Dividing plate with described positive electrode electric connection, this dividing plate has the first surface of at least a portion that defines first locellus and defines the second surface of second locellus, described first locellus and second locellus be via the dividing plate ionic communication, and described dividing plate has at least a in the following Column Properties:

Dividing plate is the compound of aluminium oxide and rare-earth oxide, perhaps

Dividing plate is the compound of aluminium oxide and transition metal oxide, perhaps

Dividing plate comprises a plurality of crystal grain that define crystal boundary, described crystal boundary defines space, brilliant crack, and do not containing sodium aluminate before the described energy storage device initial charge or after described energy storage device initial charge, do not containing described positive electrode by the space, brilliant crack that described crystal boundary defines, perhaps

Dividing plate comprises the continuous phase of alkali metal ion conductor and the continuous phase of ceramic oxygen ion conductor.

2. the energy storage device of claim 1, wherein said first locellus and described second locellus are electronic isolations.

3. the energy storage device of claim 1, wherein said second locellus be arranged on described first minute indoor.

4. the energy storage device of claim 1, wherein said second locellus is elongated and defines axis.

5. the energy storage device of claim 4, wherein said first locellus is around described axis coaxle setting.

6. the energy storage device of claim 1, wherein said dividing plate is roughly plane.

7. the energy storage device of claim 6, wherein said dividing plate is plate shaped or waveform.

8. the energy storage device of claim 6, wherein said dividing plate arching or nick.

9. the energy storage device of claim 4, wherein said dividing plate has circle, triangle, square, cross or the star cross section profile perpendicular to described axis.

10. the energy storage device of claim 1, wherein said dividing plate is the alkali metal ion conductor and comprises alkali metal-beta-alumina, alkali metal-β "-aluminium oxide, alkali metal-β-gallate or alkali metal-β "-at least a in the gallate.

11. the energy storage device of claim 10, the alkali metal ion conductor in the wherein said dividing plate do not contain the crystal boundary liquid phase that sintering forms mutually.

12. the energy storage device of claim 1, wherein said dividing plate comprise one or more metal oxides that are selected from zirconia, yittrium oxide, hafnium oxide, cerium oxide and the thorium oxide.

13. the energy storage device of claim 12, the amount of wherein said metal oxide is less than about 10 percentage by weights.

14. the energy storage device of claim 12, wherein said dividing plate comprise the zirconia of stabilized with yttrium oxide or the zirconia that scandium oxide mixes.

15. the energy storage device of claim 1, wherein said dividing plate comprise the metal oxide of one or more stabilisations in zirconia, rare-earth oxide doping of cerium oxide and the alkaline earth oxide doping of cerium oxide that is selected from the rare-earth oxide doping.

16. the energy storage device of claim 1, wherein said positive electrode also comprises aluminium or zinc.

17. the energy storage device of claim 1, wherein said positive electrode also comprise one or more metals that are selected from nickel, chromium and the iron.

18. the energy storage device of claim 1, wherein said positive electrode is made up of copper basically.

19. the energy storage device of claim 1 also comprises the negative material that is arranged in described first locellus.

20. the energy storage device of claim 1, wherein said negative material comprise one or more metals that are selected from sodium, lithium, potassium and the calcium.

21. the energy storage device of claim 20, wherein said negative material also comprises aluminium.

22. the energy storage device of claim 1, wherein said positive electrode comprise one or more halide that are selected from chloride, fluoride, bromide and the iodide.

23. the energy storage device of claim 1, wherein said positive electrode also are included in the support electrolyte greater than fusion under 150 ℃ the working temperature.

24. the energy storage device of claim 23, wherein said fusion support electrolyte and comprise the ternary melt.

25. the energy storage device of claim 24, wherein said ternary melt comprises NaCl:AlCl ₃: CuCl.

26. the energy storage device of claim 23, wherein said support electrolyte comprises sulphur or phosphorus.

27. the energy storage device of claim 1 also comprises at least one the surperficial cation promoter that is arranged at described dividing plate.

28. the energy storage device of claim 27, wherein said cation promoter material comprises selenium.

29. the energy storage device of claim 1, wherein at least one baffle surface has about 10 nanometers to about 100 microns surface roughness value (RMS).

30. the energy storage device of claim 1, hermetically-sealed construction and another sealing structure that wherein said dividing plate constitutes by means of nature of glass composition.

31. the energy storage device of claim 1, wherein said hermetically-sealed construction be in about 100 ℃ of sealings that operationally keep to about 600 ℃ temperature between described at least positive electrode and the environment, and randomly do not corrode under the situation that halogen exists or pit do not occur.

32. energy-storage system that comprises the energy storage device of claim 1.

33. the energy-storage system of claim 32, wherein said energy-storage system can be stored the energy greater than 10 kilowatt hours.

34. the energy-storage system of claim 32, wherein said energy-storage system have greater than the rated energy/weight ratio of 100 watt-hour/kilograms and greater than 160 watt-hours/liter rated energy/volume ratio.

35. the energy-storage system of claim 32, wherein said energy-storage system have the specified unit power greater than 150 watts/kilogram.

36. the energy-storage system of claim 32, wherein said energy-storage system have the power/energy ratio less than 1: 1.

37. a method comprises:

Between first locellus and second locellus, transmit sodium ion via dividing plate, described dividing plate with comprise the positive electrode electric connection of copper, and this dividing plate has at least a in the following Column Properties:

Dividing plate is the compound of aluminium oxide and rare-earth oxide, perhaps

Dividing plate is the compound of aluminium oxide and transition metal oxide, perhaps

Dividing plate comprises a plurality of crystal grain that define crystal boundary, and described crystal boundary defines space, brilliant crack, and is not being contained sodium aluminate before the energy storage device primary charging or do not contained positive electrode after the energy storage device primary charging by the space, brilliant crack that described crystal boundary defines, perhaps

Dividing plate comprises the continuous phase of sodium ion conductor and the continuous phase of ceramic oxygen ion conductor; And

Stop copper in the sodium ion transmission course, to infiltrate space, described brilliant crack.

38. a system comprises:

Can between first locellus and second locellus, transmit sodium ion and with the dividing plate of the positive electrode electric connection that comprises copper, described dividing plate has at least a in the following Column Properties:

Dividing plate is the compound of aluminium oxide and rare-earth oxide, perhaps

Dividing plate is the compound of aluminium oxide and transition metal oxide, perhaps

Dividing plate comprises a plurality of crystal grain that define crystal boundary, and described crystal boundary defines space, brilliant crack, and is not being contained sodium aluminate before the energy storage device primary charging or do not contained positive electrode after the energy storage device primary charging by the space, brilliant crack that described crystal boundary defines, perhaps

Dividing plate comprises the continuous phase of sodium ion conductor and the continuous phase of ceramic oxygen ion conductor; And be used for stoping copper to infiltrate the mechanism in space, described brilliant crack in the sodium ion transmission course.

39. an energy storage device comprises:

Dividing plate, described dividing plate have the first surface of at least a portion that defines first locellus and define the second surface of second locellus, and described first locellus and described second locellus are via described dividing plate ionic communication; And

Multiple positive electrode, described multiple positive electrode comprises first positive electrode and second positive electrode at least, described two kinds of positive electrodes are all with described dividing plate electric connection and all can form metal halide,

Condition is, if any in described first positive electrode or described second positive electrode is transition metal, then another kind of positive electrode is not iron, arsenic or tin.

40. the energy storage device of claim 39, wherein said first positive electrode comprises zinc, and described second positive electrode comprises copper.

41. the energy storage device of claim 39, wherein said first positive electrode comprises nickel, and described second positive electrode comprises copper.

42. the energy storage device of claim 39, wherein said first positive electrode comprises nickel, and described second positive electrode comprises zinc.

43. the energy storage device of claim 39, wherein said first positive electrode comprises nickel, and described second positive electrode comprises zinc, and described multiple positive electrode also comprises the 3rd positive electrode, and the 3rd positive electrode comprises copper.

44. the energy storage device of claim 39, wherein said first positive electrode comprises nickel, and described second positive electrode comprises zinc or copper, and described multiple positive electrode also comprises the 3rd positive electrode, and the 3rd positive electrode comprises molybdenum or tungsten.

45. the energy storage device of claim 39, wherein said first positive electrode comprises nickel, and described second positive electrode comprises zinc or copper, and described multiple positive electrode also comprises the 3rd positive electrode, and the 3rd positive electrode comprises tin or arsenic.

46. the energy storage device of claim 39, wherein said first positive electrode comprises zinc, and described second positive electrode comprises copper, and described multiple positive electrode also comprises the 3rd positive electrode, and the 3rd positive electrode comprises molybdenum or tungsten.

47. the energy storage device of claim 39, wherein said first positive electrode comprises zinc, and described second positive electrode comprises copper, and described multiple positive electrode also comprises the 3rd positive electrode and the 4th positive electrode, the 3rd positive electrode comprises nickel, and the 4th positive electrode comprises tin or arsenic.

48. the energy storage device of claim 39, the multiple positive electrode of wherein obeying described condition comprises two or more metals that are selected from nickel, zinc, copper, chromium and the iron.

49. the energy storage device of claim 39, wherein said first positive electrode comprises nickel, and described second positive electrode comprises aluminium or chromium.

50. the energy storage device of claim 39, wherein said first positive electrode comprises copper, and described second positive electrode comprises aluminium or chromium.

51. the energy storage device of claim 39, wherein said first positive electrode comprises zinc or copper, and described second positive electrode comprises at least two kinds in tin, arsenic, aluminium or the chromium.

52. the energy storage device of claim 39, wherein said multiple positive electrode comprise three kinds or the more kinds of metal that is selected from nickel, zinc, copper, chromium and the iron.

53. the energy storage device of claim 39, wherein said multiple positive electrode comprises nickel, zinc, copper, chromium and iron.

54. the energy storage device of claim 39 is wherein obeyed the multiple positive electrode of described condition, is made up of two kinds of metals that are selected from nickel, zinc, copper, chromium, tungsten, molybdenum and the iron in fact.

55. the energy storage device of claim 39 is wherein obeyed the multiple positive electrode of described condition, is made up of three kinds of metals that are selected from aluminium, nickel, zinc, copper, chromium, tin, arsenic, tungsten, molybdenum and the iron in fact.

56. the energy storage device of claim 39, wherein said first positive electrode is about 1: 1 to about 5: 1 with respect to the amount of described second positive electrode.

57. the energy storage device of claim 39, wherein said first positive electrode is about 5: 1 to about 20: 1 with respect to the amount of described second positive electrode.

58. the energy storage device of claim 39, wherein said first positive electrode is about 20: 1 to about 50: 1 with respect to the amount of described second positive electrode.

59. the energy storage device of claim 39, wherein said multiple positive electrode comprises one or more halide that are selected from chloride, fluoride, bromide and the iodide.

60. the energy storage device of claim 39, wherein said multiple positive electrode is included in the support electrolyte greater than fusion under about 150 ℃ working temperature.

61. the energy storage device of claim 60, wherein said fusion support electrolyte and comprise the ternary melt.

62. the energy storage device of claim 60, wherein said fusion support electrolyte and comprise binary melt.

63. the energy storage device of claim 39, wherein said fusion support electrolyte and comprise sulphur or phosphorus.

64. the energy storage device of claim 39 also comprises negative material, described negative material comprises sodium.

65. the energy storage device of claim 64, wherein said negative material also comprises aluminium or titanium.

66. the energy storage device of claim 39, wherein said dividing plate comprises β "-aluminium oxide and at least a stabilizer, described stabilizer is alkali metal oxide, alkaline earth oxide, transition metal oxide or rare-earth oxide.

67. the energy storage device of claim 66, wherein said stabilizer comprise blended metal oxide that transmits oxygen or the mixed-metal oxides that transmits oxygen.

68. the energy storage device of claim 39, wherein said dividing plate comprise at least a in zirconia, yittrium oxide, hafnium oxide, cerium oxide or the thorium oxide.

69. energy-storage system that comprises the energy storage device of claim 39.

70. the energy-storage system of claim 69, wherein said energy-storage system can be stored the energy greater than 10 kilowatt hours.

71. the energy-storage system of claim 69, wherein said energy storage device have greater than the rated energy/weight of 100 watt-hour/kilograms and greater than 160 watt-hours/liter rated energy/volume.

72. the energy-storage system of claim 69, wherein said energy storage device have the specified unit power greater than 150 watts/kilogram.

That 73. the energy-storage system of claim 31, wherein said energy storage device have is about 1 (hour ^-1) to about 10 (hour ^-1) the power/energy ratio.

74. a system comprises:

The mechanism of transmission sodium ion between first locellus and second locellus; And

With first positive electrode and second positive electrode of described transport sector electric connection, and

Condition is, if any in described first positive electrode or described second positive electrode is transition metal, then another kind of positive electrode is not iron, arsenic, or tin.

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