KR20160096071A - Sodium-halogen secondary cell - Google Patents

Abstract

There is provided a sodium-halogen secondary cell comprising a cathode compartment containing a sodium-based cathode and a cathode compartment containing a current collector disposed in the liquid cathode solution. The liquid anode solution comprises halogens and / or halides. The cell comprises a sodium ion conductive electrolyte membrane separating the cathode from the liquid anode solution. Although in some cases the sodium-based cathode is melted during battery operation, in other cases the cathode includes a sodium electrode or a sodium intercalated carbon electrode that is solid during operation.

Description

[0001] SODIUM-HALOGEN SECONDARY CELL [0002]

<Cross-reference to related application>

This application claims priority to U.S. Provisional Patent Application Serial No. 61 / 888,933, filed October 9, 2013 entitled "NASICON MEMBRANE BASED Na-I ₂ BATTERY". This application claims priority to U.S. Provisional Patent Application No. 61 / 697,608, filed September 6, 2012, entitled " SODIUM-HALOGEN BATTERY, " 61 / 777,967, filed on March 14, 2013, entitled " SODIUM-HALOGEN SECONDARY FLOW CELL &quot;, which claims priority to U.S. Provisional Patent Application Serial No. 61 / Quot; SODIUM-HALOGEN BATTERY "filed on December 12, 2012, entitled " BATTERY WITH BROMINE OR BROMIDE ELECTRODE AND SODIUM SELECTIVE MEMBRANE, " This application is a continuation-in-part of U.S. Patent Application No. 14 / 019,651, filed September 6. All of these prior patent applications are expressly incorporated herein by reference.

<STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH>

The present invention was made with government support under Agreement 1189875, granted by Sandia National Lab. The government has certain rights to the invention.

<Technical Field>

The present disclosure relates generally to batteries. More particularly, the present disclosure provides a sodium-based secondary battery (or rechargeable battery) having a liquid electrolyte solution comprising a sodium ion conductive electrolyte membrane and halogens and / or halides.

BACKGROUND OF THE INVENTION [0002] Batteries are well known devices used to store and discharge electrical energy for a variety of applications. To generate electrical energy, a battery typically converts chemical energy directly into electrical energy. Generally, a single battery includes at least one galvanic cell, wherein each cell is made of two electrically isolated half-cells, except through an external circuit. During the discharge, electrochemical reduction occurs at the anode of the cell, whereas electrochemical oxidation occurs at the cathode of the cell. Although the positive and negative electrodes in the cell do not physically touch each other, they are chemically connected by at least one (or more) ionic conducting and electrically insulating electrolyte, which can be a solid state, a liquid state, or a combination of these states have. When an external circuit or a load is connected to a terminal connected to the cathode and a terminal connected to the anode, the battery drives the electrons through the external circuit while the ions move through the electrolyte.

 The battery can be classified in various ways. For example, a battery that is only fully discharged once is often referred to as a primary battery or primary battery. In contrast, a battery that can be discharged and recharged more than once is sometimes referred to as a secondary battery or a secondary battery. The ability of a battery or battery to charge and discharge multiple times depends on the Faradaic efficiency of each charge and discharge cycle.

Sodium-based rechargeable batteries may include a variety of materials and designs, but most sodium batteries that require high Faraday efficiency use solid primary electrolyte separators, such as mostly solid ceramic primary electrolyte membranes. The main advantage of using a solid ceramic primary electrolyte membrane is that the Faraday efficiency of the derived cell is close to 100%. In fact, in almost all other battery designs, the electrode solutions in the cell can be mixed over time, resulting in reduced faraday efficiency and loss of battery capacity.

Primary electrolyte separators used in sodium batteries that require high Faraday efficiency are often made of ion conductive polymers, ionic conductive liquids or gel-impregnated porous materials, or dense ceramics. In this regard, many rechargeable sodium batteries that are currently commercially viable include a molten sodium metal cathode, a sodium beta "- alumina ceramic electrolyte separator, and a molten anode, which is a composite of molten sulfur and carbon These rechargeable batteries typically have a high power density and a relatively low power density because such conventional high temperature sodium-based rechargeable batteries have a relatively high specific energy density and only a moderate power density. It is used in certain special goods, such as fixed storage and uninterruptible power supplies, that require high specific energy densities that are not confronted.

Despite the advantageous properties associated with some conventional sodium-based rechargeable batteries, such batteries can have significant disadvantages. In one example, the sodium &bgr; "-alumina ceramic electrolyte separator is typically more conductive and is better wetted by molten sodium at temperatures above about 270 DEG C and / or the molten anode typically has a relatively high temperature (For example, temperatures of about 170 DEG C or greater than 180 DEG C), many conventional sodium-based rechargeable batteries operate at temperatures above about 270 DEG C and suffer from significant thermal management difficulties and heat sealing problems For example, some sodium-based rechargeable batteries may suffer from the dissipation of heat from the battery or the maintenance of the cathode and anode at relatively high operating temperatures. As another example, a relatively high operation of some sodium- Temperature can cause significant safety issues. Another example is the relatively high activity of some sodium-based batteries The temperature requires that these components be resistant to such high temperatures and be operable thereon. Thus, these components can be relatively costly. As another example, some conventional sodium-based batteries Can require a relatively large amount of energy to heat the battery to a relatively high operating temperature, such a battery can be expensive to operate and energy inefficient.

Thus, although sodium-based rechargeable batteries are available, there are also challenges for such batteries, including those previously mentioned. Accordingly, it would be an improvement in the relevant art to retrofit or even replace certain conventional sodium-based rechargeable batteries with other sodium-based rechargeable batteries.

The present disclosure provides a sodium-halogen secondary cell. The described sodium-halogen secondary battery may comprise any suitable component, but in some embodiments, it comprises a cathode compartment for receiving a sodium-based cathode. In this embodiment, the cell further comprises a cathode compartment for receiving a current collector disposed in a liquid anode solution comprising a halogen and / or a halide. The cell also includes a sodium ion conductive electrolyte membrane separating the cathode from the liquid anode solution.

The cathode may comprise any suitable sodium-based anode, but in some embodiments it comprises a sodium metal that is melted when the cell is operating. However, in other implementations, the negative electrode comprises a sodium anode or sodium intercalated carbon that remains solid as the cell functions. In some such implementations where the cathode remains solid when the cell is operating, the cell includes a non-aqueous anolyte solution disposed between the cathode and the electrolyte membrane.

The sodium ion conductive electrolyte membrane is a material that selectively transports sodium ions and is stable at the operating temperature of the cell and stable when in contact with the positive electrode solution and negative electrode (or nonaqueous anolyte), or alternatively, Membrane (which is used herein to refer to any suitable type of separator). In fact, some non-limiting implementations include, electrolyte membrane substantially water impermeable NaSICON- type film (e.g., a NaSELECT ^® manufactured by three llama Tech (Ceramatec) of Salt Lake City, Utah film on. Thus, in this implementation, the water impermeable electrolyte membrane allows to include an aqueous solution that can react explosively when the anode solution comes in contact with the sodium cathode.

The current collector in the anode compartment may comprise any suitable material that allows the cell to function as intended. Indeed, in some non-limiting embodiments, the current collector includes wire, felt, mesh, plate, foil, tube, foam, or other suitable current collector configuration. Additionally, the current collector may include any suitable material, but in some implementations it may be a carbon, platinum, copper, nickel, zinc, sodium intercalated cathode material (e.g., Na _x MnO ₂ ), and / Any other suitable current collector material.

The liquid anolyte solution in the anode compartment may comprise any suitable material that can conduct sodium ions to and from the electrolyte membrane, or otherwise allow the cell to function as intended. Some examples of suitable anolyte solution materials include aqueous (e.g., dimethylsulfoxide, NMF (N-methylformamide), ethylene glycol, and the like) that readily conducts sodium ions and is chemically compatible with the electrolyte membrane (E. G., Glycerol, ionic liquids, organic electrolytes, etc.) solvents. In addition, in some implementations, the positive electrode solution comprises a mixture of molten fluorosulfonylamide (e.g., 1-ethyl-3-methylimidazolium-bis (fluorosulfonyl) amide) Quot;).

The anode solution also includes halogens and / or halides. Some examples of suitable halogens include bromine, iodine, and chlorine. Similarly, some examples of suitable halides include bromide ions, polybromide ions, iodide ions, polyiodide ions, chloride ions, and polychloride ions. The halide / halide may be introduced into the anode solution in any suitable manner, but in some embodiments they are added as NaBr, NaI or NaCl.

In some implementations, the described cell is modified to limit the amount of free-floating halogen present in the anode solution and / or anode compartment. The amount of halogen in the cell can be reduced and / or adjusted in any suitable manner, but in some implementations it is capable of forming a polyhalide (e.g., Br ₃ ^- , I ₃ ^-, etc.) from free halogen molecules in the anode solution (E.g., NaBr, NaI, etc.) and / or elemental halogens (e.g., bromine, iodine, etc.) in a sufficient amount; Complexing agents capable of forming (or otherwise complexing) an adduct with a halide, halogen and / or polyhalide in the anode solution (e.g., tetramethylammonium bromide, tetramethylammonium iodide, N-methyl -N-methylmorpholinium bromide, N-methyl-N-methyl-morpholinium iodide, etc.); To the corresponding solution in the halide ion to form the halogen to the oxidation before the metal halide (for _{example, CuBr, CuI, NiBr 2,} NiI 2, ZnBr 2, ZnI 2 , and so on) and the solution can be within a halide ion and react to form The use of a current collector comprising a metal (e. G., Copper, nickel, zinc, etc.) oxidizing to form a metal ion; And any suitable combination thereof.

In some embodiments where the cell is operating at elevated temperature, there is a complexing agent for complexing with an excess of sodium halide (e.g., excess I ₂ , Br ₂ ) or formed halogen, Gas to be converted into gas) may be preferable. Indeed, in some embodiments, up to a third of NaI (sodium halide or complexing agent) can be added to the system. In addition, in the embodiment using I ₂ , the casing of the battery may be made of peak stainless steel whose interior is Teflon ®, but other inexpensive materials such as other types of stainless steel may be used. In another embodiment, the cathode chamber may be made of Teflon® lining and polyetheretherketone (PEEK). Teflon® is a registered trademark of DuPont Company.

In some embodiments, the battery includes a first reservoir in fluid communication with the anode compartment. In this embodiment, the reservoir is connected to a pumping mechanism configured to allow the liquid anolyte solution to flow from the reservoir and pass through the current collector in the anode compartment. In some embodiments, the cell also includes a second reservoir in fluid communication with the cathode compartment. In this embodiment, the reservoir is connected to a pumping mechanism configured to allow the molten cathode (or non-aqueous anode liquid) to flow from the reservoir and pass through the cathode compartment.

The described secondary cell can operate at any suitable operating temperature. In fact, in some implementations where the cathode melts when the cell is operating, the cell functions with the temperature of the cathode being from about 100 ° C to about 150 ° C (eg, about 120 ° C ± 10 ° C) Or recharged). Additionally, in some implementations where the cathode remains in a solid state when the cell functions, the temperature of the cathode is maintained at less than about 60 占 폚 (e.g., about 20 占 폚 占 about 10 占 폚). Additional embodiments may be designed in which the battery operates at less than 250 占 폚, or less than 200 占 폚, or less than 180 占 폚, or less than 150 占 폚.

These features and advantages of the embodiments will become more fully apparent from the following description and appended claims.

Figure 1 shows a schematic diagram of a representative embodiment of a sodium-halogen secondary cell during discharge comprising a molten sodium cathode;
Figure 1A shows a schematic diagram of a representative embodiment of a sodium-halogen secondary cell during discharging comprising a molten sodium cathode and a pumping mechanism;
Figure 2 shows a schematic diagram of a representative embodiment of a rechargeable sodium-halogen secondary cell comprising a molten sodium cathode;
Figure 2a shows a schematic diagram of an exemplary embodiment of a rechargeable sodium-halogen secondary cell comprising a molten sodium cathode and a pumping mechanism;
Figure 3 shows a cross-sectional perspective view of an exemplary embodiment of a sodium-halogen secondary cell comprising a tubular design in which the cathode compartment is at least partially disposed within the anode compartment of the battery;
Figure 3a shows a cross-sectional perspective view of another exemplary embodiment of a sodium-halogen secondary cell comprising a tubular design in which the cathode compartment is at least partially disposed within the anode compartment of the battery;
Figure 4 shows a schematic diagram of a representative embodiment of a sodium-halogen secondary cell comprising a non-aqueous anolyte solution disposed between a solid cathode and a cathode and a solid sodium conductive electrolyte membrane;
4A shows a schematic diagram of a representative embodiment of a sodium-halogen secondary cell comprising a solid negative electrode, a pumping mechanism and a non-aqueous anode liquid solution disposed between the negative electrode and the solid sodium conductive electrolyte film;
Figures 5A and 5B each contain a cross-sectional micrograph of an exemplary embodiment of a NaSICON-type material suitable for use in some embodiments of the present invention;
Figure 6 shows a schematic representation of an exemplary embodiment of a sodium-halogen secondary cell in which the anode solution in the cell comprises molten sodium halide and molten sodium fluorosulfonylamide;
6A shows a schematic diagram of an exemplary embodiment of a sodium-halogen secondary cell having a pumping mechanism, wherein the anode solution in the cell comprises molten sodium halide and molten sodium fluorosulfonylamide;
Figure 7a shows a schematic diagram of an exemplary embodiment of a sodium-halogen secondary cell having a pumping mechanism configured to allow the anode solution to flow through the anode compartment and the cathode to flow through the cathode compartment of the cell;
Figs. 8-12 show graphs showing experimental results obtained from a trial run of a representative embodiment of an experimental cell, respectively; Fig.
Figure 13 is a schematic view of another cell according to the present disclosure;
Figure 14 is a schematic view of another battery according to the present disclosure;
15 is a schematic view of another battery according to the present disclosure;
16 is a schematic view of another battery according to the present disclosure;
Figs. 17-21 show graphs showing experimental results obtained from a trial run of a representative embodiment of an experimental cell, respectively;
Figures 22a and 22b show a schematic diagram of a secondary battery similar to Figures 2 and 2a above, showing the details of battery chemistries 1 and 2.

Reference throughout this specification to "an embodiment," " an embodiment, "or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrases throughout this specification, " in one embodiment, "in an embodiment," in another embodiment, "and similar language are not necessarily all referring to the same embodiment. Further, although the following description refers to several embodiments and examples of various elements and aspects of the described invention, it will be appreciated that all described embodiments and examples are to be considered in all respects only as illustrative and not in any way limiting Should not.

Additionally, the features, structures, or characteristics of the invention described may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to provide a thorough understanding of embodiments of the present invention, such as examples of suitable sodium-based cathodes, liquid anion solutions, current collectors, sodium ion conductive electrolyte membranes, and the like. However, one of ordinary skill in the pertinent art will recognize that the invention may be practiced without one or more of the specific details, or with other methods, components, materials, and so on. In other embodiments, well-known structures, materials, or operations are not shown or described in detail in order to avoid obscuring aspects of the invention.

As described above, the secondary battery can be discharged and recharged, and battery arrangements and methods for both states are described herein. Although the term "recharge" includes a second charge in various forms, one of ordinary skill in the relevant art will appreciate that the discussion of recharge is valid for and applicable to the first or initial charge, and vice versa I will understand. Thus, for purposes of this specification, the terms "refilled "," refilled ", and "refillable" will each be interchangeable with the terms "refilled "," refilled "

This embodiment provides a sodium-halogen secondary battery including a liquid anode solution containing at least one of halogens and halides and a cathode containing sodium. 1 illustrates that the sodium-halogen secondary battery 10 comprises a cathode compartment 15 comprising a sodium-based cathode 20, a liquid catholyte solution 35 , A first terminal 45 and a second terminal 50. The positive electrode compartment 25 includes the current collector 30 disposed within the negative electrode current collector 30, the sodium ion conductive electrolyte membrane 40 separating the negative electrode from the positive electrode solution, Lt; / RTI &gt; To provide a better understanding of the battery 10 described, a brief description of how the battery functions is provided below. After such a discussion, the components of each cell shown in Fig. 1 will be discussed in more detail.

Turning now to the manner in which the sodium-halogen secondary cell 10 functions, the cell can actually function in any suitable manner. For example, Figure 1 shows that when sodium (10) is discharged and electrons (e ^- ) flow out of the cathode (20) (for example, through the first terminal To form sodium ions (Na &lt; ^{+ &} gt ^; ). 1 shows that these sodium ions are respectively transported from the sodium-based cathode 20 to the anode solution 35 through the sodium ion conductive electrolyte membrane 40.

By way of contrast, FIG. 2 shows the battery 10 when the secondary cell 10 is recharged and electrons e ^- flow from an external power source (not shown) such as a recharger into the sodium- (As shown in FIG. 1). Specifically, FIG. 2 shows that when the battery 10 is refilled, sodium ions (Na ⁺ ) are respectively transported from the anode solution 35 to the cathode 20 through the electrolyte membrane 40, where sodium ions are reduced To form a sodium metal (Na).

Hereinafter, in connection with the various components of the battery 10, the battery (described above) may include a cathode compartment 15 and an anode compartment 25. In this regard, the two compartments may be of any suitable shape or size and may have any other suitable characteristic that allows the battery 10 to function as intended. By way of example, the cathode compartment and anode compartment may be tubular, rectangular, or any other suitable shape. In addition, the two compartments may have any suitable spatial relationship to each other. For example, Figure 2 shows some embodiments in which the cathode compartment 15 and the anode compartment 25 are close together, while Figure 3 shows that one compartment (e. G., The cathode compartment 15) For example, the anode compartment 25), while the contents of the two compartments remain separated by the electrolyte membrane 40 and any other compartment walls.

In connection with the cathode 20, the battery 10 may include any suitable sodium-based cathode 20 that allows the battery 10 to function (e.g., discharge and recharge) as intended . Some examples of suitable sodium-based cathode materials include, but are not limited to, substantially pure sodium samples, sodium alloys comprising any other suitable sodium-containing cathode material, and sodium intercalation materials. Indeed, in certain embodiments, the cathode comprises or consists of a predetermined amount of substantially pure sodium. However, in another embodiment, the cathode comprises or consists of a sodium intercalating material.

When the cathode 20 comprises a sodium intercalation material, the intercalation material causes the sodium metal in the cathode to oxidize to form sodium ions (Na &lt; ^{+ &} gt ^; ) when the cell 10 is discharged, But may include any suitable material that allows sodium ions to be reduced and intercalated with the intercalating material. In some embodiments, the intercalating material also includes a material that will cause the resistance of the electrolyte membrane 40 to increase little or no at all (discussed below). That is, in some embodiments, the intercalating material facilitates transport of sodium ions therethrough and has little or no adverse effect on the rate at which sodium ions pass from the cathode compartment 15 to the anode compartment 25 (and vice versa) .

In some embodiments, the intercalation material in the cathode 20 is an intercalated sodium metal (e.g., graphite, mesoporous carbon, boron-doped diamond, carbon and / or graphene) / &Lt; / RTI &gt; or a sodium metal alloy). Thus, some embodiments of the cathode include a sodium intercalated carbon material.

When the battery 10 is activated (e.g., discharged and / or charged), the sodium-based cathode 20 may be at any suitable temperature that allows the cell to function as intended. Indeed, in some embodiments (e. G., Embodiments wherein the cathode comprises a sodium metal), the battery functions at any suitable operating temperature to cause the cathode to melt when functioning. In fact, in some embodiments in which the cell comprises a molten cathode, the temperature (or operating temperature) of the cathode when the cell functions is from about 100 캜 to about 155 캜. In another embodiment, the operating temperature of the cell is from about 110 캜 to about 150 캜. In another embodiment, the operating temperature of the cell is from about 115 캜 to about 125 캜. In another embodiment in which the cathode melts when the cell is operating, the cell has an operating temperature that falls within any of the sub-ranges of the operating temperature range described above (e.g., about 120 ° C ± 2 ° C). In a further embodiment, the cell may operate at higher temperatures, such as less than 250 占 폚, less than 200 占 폚, less than 180 占 폚, and the like.

In embodiments where the cathode 20 remains a solid when the cell 10 is in operation (e.g., embodiments that include a negative electrode intercalated carbon and / or a solid sodium anode) Lt; RTI ID = 0.0 &gt; operating temperature. &Lt; / RTI &gt; In fact, in some embodiments where the cathode is solid when the cell is functioning, the operating temperature of the cell is from about -20 캜 to about 98 캜. In other such embodiments, the operating temperature of the cell is from about 18 [deg.] C to about 65 [deg.] C. In yet another such embodiment, the operating temperature of the cell is from about 20 캜 to about 60 캜. In another embodiment, the operating temperature of the cell is from about 30 캜 to about 50 캜. In another embodiment in which the cathode remains in a solid state when the cell is operating, the cell has an operating temperature that falls within any of the sub-ranges of the operating temperature range described above (e.g., about 20 ° C ± 10 ° C).

Although the cathode 20 is in direct contact with (and / or wetted with) the electrolyte membrane 40 in some embodiments (e. G., When the cathode 20 is melted when the battery 10 is operating) In some embodiments (e. G., When the cathode remains solid when the cell functions), the cathode is not in direct contact with the electrolyte membrane at all. 4 shows that in some embodiments in which the cathode 20 remains solid when the cell 10 is operating the non-aqueous anode liquid solution 65 separates the cathode 20 from the electrolyte membrane 40 . In such embodiments, the non-aqueous anolyte solution may include, without limitation, providing a physical buffer between the cathode and the electrolyte membrane such that the cathode is either cracked or runs to prevent (or at least disturb) the electrolyte membrane And can perform any suitable function.

When the battery 10 comprises a non-aqueous anode liquid solution 65, the anolyte solution is chemically compatible with the cathode 20 and the electrolyte membrane 40 and sodium ions from the cathode to the electrolyte membrane and vice versa And may include any suitable chemical that is sufficiently conductive to allow it to pass. In this regard, some examples of suitable non-aqueous anode liquids include propylene carbonate; Ethylene carbonate; One or more organic electrolytes, an ionic liquid, a polar aprotic organic solvent, a polysiloxane compound, an acetonitrile-based compound, and the like; Ethyl acetate; And / or any other suitable non-aqueous liquids and / or gels. For a more detailed description of a suitable non-aqueous anolyte solution, see U.S. Patent Application Publication No. 2011/0104526, filed November 5, 2010; The entire disclosure of which is incorporated herein by reference.

Hereinafter, with respect to the sodium ion conductive electrolyte membrane 40, the membrane may comprise any suitable material that selectively transports sodium ions and allows the cell 10 to function as the non-aqueous anode solution 35 or the aqueous anode solution 35 . &Lt; / RTI &gt; In some embodiments, the electrolyte membrane comprises a NaSICON-type (sodium Super Ion Conductive) material. If the electrolyte membrane comprises a NaSICON-type material, the NaSICON-type material may comprise any known or novel NaSICON-type material suitable for use in the battery 10 described. Some suitable examples of NaSICON-type compositions include Na ₃ Zr ₂ Si ₂ PO ₁₂ , Na _{1 + x} Si _x Zr ₂ P _{3 - x} O ₁₂ (Where, x would be approximately 1.6 to about 2.4), Y- doped _{NaSICON (Na 1 + x + y} Zr 2 - y Y y Si x P 3 - x O 12, Na 1 + x Zr 2 - y Y y Si _{3 x} P _{- x,} and _-y O ₁₂ (wherein, x = 2, y = 0.12 _{Im)), Na 1-x Zr} 2 Si x P 3-x O 12 ( wherein, x is from about 0 to about 3, some when include, but being from about 2 to about 2.5), and Fe- doped _{NaSICON (Na 3 Zr 2/3} Fe 4/3 P 3 O 12), but is not limited thereto. Indeed, in certain embodiments, the NaSICON-type film comprises Na ₃ Si ₂ Zr ₂ PO ₁₂ . In another embodiment, NaSICON-type membranes are prepared by the method described in Serramatech, Inc. Comprises one or more materials NaSELECT ^® (manufactured by United States Salt Lake City). In another embodiment, the NaSICON-type film comprises a known or new composite, cermet-supported NaSICON film. In such embodiments, the composite NaSICON film may include, without limitation, any suitable component, including a porous NaSICON-cermet layer comprising NiO / NaSICON or any other suitable cermet layer, and a dense NaSICON layer. In another embodiment, the NaSICON film comprises monoclinic ceramics.

In some embodiments (shown in FIGS. 5A and 5B), the electrolyte membrane 40 includes a first porous substrate 70 that supports a relatively thin dense NaSICON-type material layer 75 (e.g., a relatively thick porous NaSICON - type material). In such embodiments, the first porous substrate may perform any suitable function, including acting as a scaffold for the dense layer. As a result, some implementations of the electrolyte membrane can minimize ohmic polarization losses at the relatively low operating temperatures discussed above. Additionally, in some embodiments, by having both the porous scaffold and the dense NaSICON-type layer, the electrolyte membrane can be made to have a relatively high mechanical strength (e.g., to allow the pressure within the cell 10 to change as the cell is pressurized, And the like).

The porous substrate layer 70 can be any suitable thickness, but in some embodiments it is from about 50 microns to about 1250 microns thick. In another embodiment, the porous substrate layer is from about 500 microns to about 1,000 microns thick. In another embodiment, the porous substrate layer is from about 700 [mu] m to about 980 [mu] m. In another embodiment, the porous substrate layer has a thickness that falls within any suitable sub-range of the above range (e.g., from about 740 탆 to about 960 탆).

The dense layer 75 on the substrate layer 70 can be any suitable thickness that allows the cell 10 to function as intended. In fact, in some embodiments, the dense layer (e. G., A dense NaSICON-type material layer) has a thickness of about 20 microns to about 400 microns. In another embodiment, the dense layer has a thickness of about 45 [mu] m to about 260 [mu] m. In another embodiment, the dense layer has a thickness that falls in any sub-range (e.g., about 50 占 퐉 占 10 占 퐉) of the thickness described above.

The electrolyte membrane 40 may have any suitable sodium conductivity that allows the cell 10 to operate as intended. Indeed, in some embodiments (where the electrolyte membrane comprises NaSELECT ^® or another suitable NaSICON-type material), the electrolyte membrane has a permeability of about 4 × 10 ^-3 S cm ^-1 to about 20 × 10 ^-3 S cm ^-1 Its optional sub-range).

If the electrolyte membrane 40 comprises a NaSICON-type material, the NaSICON-type material may provide a number of beneficial properties to the battery 10. As an example, since the NaSICON-type material is substantially impermeable to water and stable in the presence of water, unlike the sodium? "- alumina ceramic electrolyte separator, the NaSICON- (Otherwise it would be incompatible with the sodium anode 20.) Thus, the use of a NaSICON-type membrane as the electrolyte membrane allows the cell to have a wide range of battery chemistries. The NaSICON-type As an example of another advantageous characteristic that may be associated with the membrane, such membrane selectively transports sodium ions but does not mix cathode 20 and anode solution 35, In fact, some NaSICON-type materials (e.g., NaSELECT ^® membranes) can be self-discharging, Intersystem, and / or solid-solid permselectivity of the material.

In connection with the current collector 30, the battery 10 may include any suitable current collector that allows the battery to be charged and discharged as intended. For example, the current collector may comprise any current collector configuration that has been successfully used in a sodium-based rechargeable battery system. In some embodiments, the current collector may comprise one or more of wire, felt, foil, plate, parallel plate, tube, mesh, mesh screen, foam (e.g. metal foil, carbon foam etc.) . Indeed, in some embodiments, the current collector comprises a configuration having a relatively large surface area (e.g., one or more mesh screens, metal foams, etc.).

The current collector 30 may comprise any suitable material that allows the cell 10 to function as intended. In this regard, some non-limiting examples of suitable collector materials include carbon, platinum, copper, nickel, zinc, sodium intercalation materials (e.g. Na _x MnO ₂ ), nickel foams, nickel, Halide (e. G., Sulfur chloride), and / or another suitable material. In addition, these materials may be present together or in combination. However, in some embodiments, the current collector includes carbon, platinum, copper, nickel, zinc, and / or sodium intercalation materials (e.g., Na _x MnO ₂ ).

The current collector 30 may be disposed at any suitable location within the anode compartment 25 to allow the battery 10 to function as intended. However, in some embodiments, the current collector is disposed (for example, as shown in Fig. 3) or adjacent thereto (as shown in Fig. 6) on the electrolyte membrane 40, for example.

Hereinafter, with respect to the positive electrode solution 35, the solution may comprise any suitable sodium ion conductive material that allows the battery 10 to function as intended. Indeed, in some embodiments, the anode solution comprises an aqueous or non-aqueous solution. In this regard, some examples of suitable aqueous or water-compatible solutions include aqueous solutions of dimethylsulfoxide ("DMSO"), water, formamide, N-methylformamide (NMF), ethylene glycol, sodium hydroxide Aqueous solution, and / or any other aqueous solution chemically compatible with the sodium ion and electrolyte membrane 40. Indeed, in some embodiments, the positive electrolyte solution comprises NMF, formamide and / or DMSO.

In some embodiments, the anode solution 35 comprises a non-aqueous solvent. In such an embodiment, the anode solution may comprise any suitable non-aqueous solvent that allows the cell 10 to function as intended. Some examples of such non-aqueous solvents include, without limitation, glycerol, ethylene, propylene, and / or sodium ions and any other non-aqueous solution chemically compatible with electrolyte membrane 40.

In an embodiment that includes some embodiments (e.g., a molten sodium cathode 20 and a sodium intercalation current collector 30 (e.g., Na _x MnO ₂ ), shown in FIG. 6), the anode solution 35 includes a molten sodium-FSA (sodium-bis (fluorosulfonyl) amide) electrolyte. In fact, Na-FSA has a melting point of about 107 ° C (Na-FSA melts at some typical operating temperatures of the battery 10) and has a conductivity in the range of about 50-100 mS / cm ² , In an embodiment, Na-FSA serves as a useful solvent (e.g., in the case of molten sodium halide (NaX where X is selected from Br, I, Cl, etc.) Structure:

If the anode solution 35 comprises Na-FSA, the solution may contain any suitable fluorosulfonylamide capable of conducting sodium ions to or from the electrolyte membrane, or otherwise allowing the cell 10 to function as intended . Some examples of suitable fluorosulfonyl amides include, without limitation, 1-ethyl-3-methylimidazolium- (bis (fluorosulfonyl)) amide ("[EMIM] [FSA]") Materials.

In some embodiments, the anode solution 35 also comprises one or more halogens and / or halides. In this regard, halogens and halides, and polyhalides and / or metal halides formed therefrom (e.g., where the current collector 30 comprises a metal such as copper, nickel, zinc, etc. discussed below) May perform any suitable function, including, without limitation, acting as the anode when the cell 10 is operating. Some examples of suitable halogens include bromine, iodine, and chlorine. Similarly, some examples of suitable halides include bromide ions, polybromide ions, iodide ions, polyiodide ions, chloride ions, and polychloride ions. The halide / halide may be introduced into the anode solution in any suitable manner, but in some embodiments they are added as NaX where X is selected from Br, I, Cl, and the like.

In some embodiments in which the anode solution 35 comprises a halogen ("X") (eg, bromine or iodine) and / or a halide, the cell operates in the cathode 20, anode / 30), and in the overall reaction of the cell:

Cathode Na ↔ Na ⁺ + 1e ^-

Anode 2X ^- ↔ X ₂ + 2e ^-

Total 2Na + X ₂ ↔ 2Na ⁺ + 2X ^-

Thus, when X comprises iodine, the cell 10 may have the following theoretical chemistry and theoretical voltage (V) and theoretical specific energy (Wh / kg):

Cathode Na ↔ Na ⁺ + 1e ^- (-2.71 V)

Anode 2I ^- ↔ I ₂ + 2e ^- (0.52 V)

Total 2Na + I ₂ ↔ 2Na ⁺ + 2I ^- (3.23 V) (581 Wh / kg)

In addition, where X comprises bromine, the cell may have the following theoretical and theoretical ratios of the following chemical reactions and theoretical specific energies:

Cathode Na ↔ Na ⁺ + 1e ^- (-2.71 V)

Anode 2Br ^- ↔ Br ₂ + 2e ^- (1.08 V)

Total 2Na + Br ₂ ↔ 2Na ⁺ + 2Br ^- (3.79 V) (987 Wh / kg)

It has been observed that the actual charge transport reaction in the anode / current collector 30 can occur in at least two stages. These two potential responses are shown below and are named Battery Chemistry 1 (schematically shown in Figure 22a for battery recharging) and Battery Chemistry 2 (schematically shown in Figure 22b for battery chemistry recharging). It has been observed that these reactions may be individual steps of a multistage reaction, or that one step may predominate over the other depending on the battery conditions.

Anode X ₃ ^- + 2e ^- ↔ 3X ^- (Battery chemistry 1)

anode 3X₂ +2e^- ↔ 2X₃ ^- (Battery Chemistry 2)

all 2Na + X₃ ^-↔ 2Na⁺ + 3X^- (Battery Chemistry 1)

Total 2Na + 3X ₂ ↔ 2Na ⁺ + 2X ₃ ^- (Battery chemistry 2)

It will be appreciated that there are at least two potential reactions (named as different "battery chemistry" numbers) that occur in the anode / current collector 30.

When X comprises iodine, the battery 10 may have the following chemical reaction and the following theoretical voltage (V vs. SHE (standard hydrogen electrode)) and theoretical specific energy (Wh / kg):

Cathode Na ↔ Na ⁺ + 1e ^- (-2.71 V)

Anode I ₃ ^- + 2e ^- ↔ 3I ^- (0.29 V, Chemistry 1)

Anode 3I ₂ + 2e ^- ↔ 2I ₃ ^- (0.74 V, chemical 2)

all 2Na + I₃ ^- ↔ 2Na⁺ + 3I^- (2.8 V, chemical 1) (388 Wh / kg)

All 2Na + 3I ₂ ↔ 2Na ⁺ + 2I ₃ ^- (3.25 V, Chemical 2) (193 Wh kg)

The charging reaction at the anode can take place in two steps: 1) from iodide to triiodide and 2) from triiodide to iodine. Similarly, the discharge reaction at the anode can take place in two steps: 1) from iodine to triiodide and 2) from triiodide to iodide. Alternatively, the charge and discharge reactions may occur using a combination of the above reaction chemistries.

When X comprises bromine, the cell 10 may have the following chemical reaction and the following theoretical voltage (V vs. SHE) and theoretical specific energy (Wh / kg):

Cathode Na ↔ Na ⁺ + 1e ^- (-2.71 V)

Anode Br ₃ ^- + 2e ^- ↔ 3Br ^- (0.82 V, chemical 1)

Anode 3Br ₂ + 2e ^- ↔ 2Br ₃ ^- (1.04 V, chemical 2)

all 2Na + I₃ ^- ↔ 2Na⁺ + 3I^- (3.53 V, chemical 1) (658 Wh / kg)

all 2Na + 3I₂ ↔ 2Na⁺ + 2I₃ ^- (3.75 V, chemical 2) (329 Wh kg)

The charging reaction at the anode can take place in two steps: 1) from bromide to tribromide and 2) from tribromide to bromine. Similarly, the discharge reaction at the anode can take place in two steps: 1) from bromine to tribromide and 2) from tribromide to bromide. Alternatively, the charge and discharge reactions may occur using a combination of the above reaction chemistries.

The combination of Battery Chemistry 1, Battery Chemistry 2, and Battery Chemistry 1 and 2 occurring at the anode includes, but is not limited to, aqueous and non-aqueous sodium iodide solution, voltage limit, additive, concentration of solution, The equilibrium state between iodine and iodine (polybromide and bromine), the presence of free iodine (free bromine) at operating temperature, and the like.

The various components in the anode solution 35 can be present in the cell at any suitable concentration that allows the cell 10 to function as intended.

In some embodiments, a halogen (e.g., bromine, iodine, or chlorine) is formed in the cell 10 when the cell 10 is activated (e.g., charged). In this regard, halogens can have a number of effects when the cell functions. In one example, the halogen produced in the anode solution 35 may have a relatively high vapor pressure, which may eventually expose the cell rule to undesirable pressures. In another example, the halogen in the anode solution reacts with other reagents in the solution to form undesirable chemicals, such as HOX and / or HX where X is selected from Br, I, etc., when the anode solution is water- Can be formed. In some implementations, in order to reduce and / or prevent problems that may be associated with halogens generated in the anode solution, the cell is modified to provide a total of the elemental halogens (e.g., bromine, iodine, etc.) present in the anode solution Reduce the amount. In such an implementation, the cell may be modified in any suitable manner to allow the cell to operate while controlling the amount of halogen present in the anode solution.

In some embodiments, to reduce the amount of halogen in the anode solution 35, the solution may be treated with an excess of sodium halide (e.g., sodium bromide, sodium iodide, sodium chloride, etc.) and / For example, bromine, iodine, chlorine, etc.). In such embodiments, the anode solution is one or more poly halide (e. _{^{G., Br 3 -, I 3 -}} , Cl 3 - , etc.), any suitable amount of sodium halide and / or to be formed in the cathode solution was 35 (Shown in Figs. 2 and 2a, wherein X represents Br, I or Cl). In this embodiment, the polyhalide is still electroactively similar to its corresponding halogen, but may have a lower vapor pressure than its corresponding halogen.

In some embodiments, to reduce the amount of halogen in the anolyte 35, the anolyte solution may be treated with a halide, a halide and / or a polyhalide and an adduct (e. G., A halide-amine adduct, halide- Additions, and the like) or one capable of complexing therewith. In this regard, the complexing agent may include any chemical capable of forming adducts and / or complexes with halogens, halides and / or polyhalides in the anode solution. Some non-limiting examples of such complexing agents include at least one of a bromide-amine adduct, an iodide-amine adduct, a chloride-amine adduct, a tetramethylammonium halide (e.g., Tetramethylammonium chloride), ammonium compounds, N-methyl-N-methyl-morpholinium halide, and the like. In fact, in some embodiments in which the anode solution comprises NaBr / Br ₂ , the complexing agent comprises tetramethylammonium bromide, which reacts with the bromine to form tetramethylammonium tribromide. 4, the negative electrode compartment 15 includes a non-aqueous anode liquid 65, the positive electrode solution 35 includes NaBr / Br ₂ , In embodiments where the total (30) comprises carbon), the complexing agent comprises N-methyl-N-methylmorpholinium bromide.

In another embodiment, in order to reduce the amount of halogen produced in the anode solution 35, the cell 10 is formed of a metal current collector (not shown) forming a metal halide corresponding to the halide ion in the solution and the metal used in the current collector 30), the generation of halogens (e.g., bromine, iodine, chlorine, etc.) is avoided. This process may be performed in any suitable manner, but in some embodiments it relies on the metal in the current collector to be oxidized before the halide ions in the anode solution are oxidized to form the corresponding halogens. Thus, as a result, the non-volatile metal halides (for example, CuBr, NiBr _2, ZnBr _2, CuI, NiI _2, ZnI _2, etc.) are formed. In this regard, the current collector may include any suitable metal capable of avoiding the formation of halide by forming a metal halide when the cell is operating. Some non-limiting examples of such metals include copper, nickel, zinc, combinations thereof, and alloys thereof. In this regard, some examples of corresponding half-cell reactions for a cell comprising such a metal current collector include:

Cu + X ^- &gt; CuX + 1e ^-

Ni + 2X ^- &lt; ^- &gt; NiX ₂ + 2e ^-

Zn + 2X ^- &lt; ^- &gt; ZnX ₂ + 2e ^-

In addition, an example of a full-cell reaction for a NaBr / Br ₂ cell 10 comprising a nickel current collector 30 is as follows:

2Na + NiBr _2? 2NaBr + Ni

A battery including the metal current collector 30 can generate a wide variety of voltage ranges but the battery 10 contains NaBr / Br ₂ in the positive electrode solution 35 and the current collector contains copper, nickel or zinc In some cases, the voltages generated by such a cell are about 2.57 V, about 2.61 V, and about 2 V, respectively.

In some other embodiments, to reduce the total amount of halogens (e.g., bromine, iodine, etc.) in the anode compartment 25, the battery 10 may include any suitable combination of the above techniques Is modified. By way of non-limiting example, some embodiments of the battery include a current collector 30 comprising copper, nickel, zinc, or another suitable metal, and the anolyte solution 35 comprises a complexing agent, an excess of sodium halide, / &Lt; / RTI &gt; or an excess of elemental halogen.

In the following, with respect to terminals 45 and 50, the battery 10 may include any suitable terminal that can electrically connect the battery to an external circuit (not shown), for example, to one or more batteries without limitation . In this regard, the terminal includes any suitable material, and can be any suitable shape and any suitable size.

 Hereinafter, in Figs. 1A and 2A, further embodiments of the battery 10 are described. Figures 1A and 2A are similar to the embodiment shown in Figures 1 and 2, respectively; Figures 1A and 2A include additional components (Figure 1A shows the discharge of the battery 10 while Figure 2A shows the charge of the battery 10). 1a and 2a illustrate that the sodium-halogen secondary battery 10 includes a negative electrode compartment 15 comprising a sodium-based negative electrode 20 and a current collector 30 disposed within a liquid positive electrode solution 35 A first terminal 45, a second terminal 50, an external reservoir 55 for receiving the positive electrode solution, and a positive electrode compartment 25 for separating the negative electrode from the negative electrode solution, And a pumping mechanism (60) configured to flow the solution out of the reservoir and through the current collector in the anode compartment.

In the following, with respect to the pumping mechanism 60, the battery 10 may include any suitable pumping mechanism capable of allowing fluid to flow out of the reservoir 55 and into the battery. In fact, FIG. 7A is a schematic diagram of a battery 10 in which in some embodiments a battery 10 is configured to pump a first reservoir 55 and an anode solution 35 from the reservoir to pass through the current collector 30 in the anode compartment 25. [ Mechanism 60 shown in FIG. In some embodiments (also shown in FIG. 7A), the battery 10 is also connected to a second reservoir 56 and a second pumping mechanism 62. In this embodiment, the second pumping mechanism is configured such that liquid (e.g., molten sodium, non-aqueous anolyte 65, secondary anolyte, etc.) from the second reservoir 56 flows into the cathode compartment 15 And may include any suitable pump capable of flowing through it. This configuration always reduces the total amount of sodium in the cathode compartment so that the anode solution 35 can be supplied to the negative electrode 35. The pumping mechanism allows the fluid to pass through the negative compartment, Thereby reducing the damage and / or risk that may occur when contacting the substrate 20. Additionally, in some embodiments, by pumping the anode solution through the anode compartment, the cell can limit the amount of anode solution present in the cell, thereby limiting or controlling the amount of halogen present in the cell.

When the battery 10 is connected to one or more pumping mechanisms (e. G., 60 and 62) and / or to a reservoir (e. G., 55 and 56) (E.g., the anode compartment 25 and / or the cathode compartment 15) at any suitable rate that allows the fluid to function as it is. In this regard, the particular flow rate of the various embodiments of the battery will depend on the solubility of the various species in the anode solution 35, the components of the cathode compartment 15, and / or the intended charging and / or discharging rate of the cell .

Pumping mechanisms (e. G., 60 and 62) and / or reservoirs (e. G., 55 and 56) may be added to other embodiments . &Lt; / RTI &gt; For example, FIG. 4A shows an embodiment of a battery 10 similar to that described in connection with FIG. 4A, a pumping mechanism 60 and a reservoir 55 were added to the battery 10 to pump the positive electrode solution 35 so that the positive electrode solution 35 came into contact with the electrode 30. 6A, this battery 10 is similar to that shown in Fig. 6, but the battery 10 is not used for pumping the positive electrode solution 35 so that the positive electrode solution 35 comes into contact with the electrode 30 And a pumping mechanism 60, and a reservoir 55 is added to the battery 10. It should further be noted that the embodiment of FIG. 7A in which one or more pumping mechanisms 60, 62 and / or one or more reservoirs 55, 56 have been removed may also be constructed.

1a, 2a, 3a, and 4a, 6a and 7a, in at least some embodiments, may be formed of any suitable size, such as, for example, an anode compartment 15 and an anode compartment 25. In other embodiments, The anode compartment 25 is relatively small such that a substantial portion is stored in the exterior of the anode compartment (e.g., at least one external reservoir 55 configured to hold a portion of the anode solution). This configuration can provide various features for the battery 10, but in some embodiments, by having a relatively small anode compartment, the battery can be made to have a relatively small amount of anode solution in the cathode compartment, So that a relatively large portion can be brought into contact with the current collector 30.

In addition to the components described above, the battery 10 may optionally include any other suitable components and features. By way of non-limiting example, FIG. 6 shows that some embodiments of the battery 10 include one or more thermal management systems 80. In such an embodiment, the battery may comprise any suitable type of thermal management system capable of holding the battery within a suitable operating temperature range. Some examples of such thermal management systems include, but are not limited to, heaters, heat exchangers, coolers, one or more temperature sensors, and / or suitable temperature control circuits.

As another example of another suitable component that may be used in the battery 10, some embodiments of the battery include one or more current collectors (not shown) between the reservoir 55 and the positive electrolyte compartment 25 do. This current collector may perform any suitable function, but in some embodiments, the current collector may comprise a halogen (e.g., bromine, iodine, etc.) from the liquid anolyte solution 35 as the solution flows through the current collector, . &Lt; / RTI &gt;

As another example, the battery 10 may be modified in any suitable manner to accommodate the transport of sodium from the cathode compartment 15 to the anode compartment 25 during discharge. In this regard, some embodiments of the described battery 10 include a volume compensating battery casing (not shown).

As another example, the anode solution 35 may comprise any other suitable component that allows the cell 10 to function as described herein. Indeed, in some embodiments, the anode solution is a mixture of carbon (e.g., ground carbon, carbonaceous material, etc.) and / or a solution that is sodium conductive and chemically compatible with electrolyte membrane 40 and current collector 30 &Lt; / RTI &gt;

As another example, the battery 10 may be modified in any suitable manner so as to still allow the cell to function as intended and to improve the safety of the cell. Indeed, in some embodiments, the battery includes one or more pressure reducing valves (not shown). In another embodiment, the battery comprises at least one protective outer cover. In another embodiment, a cell is split into two or more smaller cells to reduce any risk associated with a damaged or malfunctioning cell. In another embodiment, in addition to the electrolyte membrane 40, the cell may include one or more additions between the cathode 20 and the anode solution 35 to minimize possible exposure that may occur between the cathode and anode solutions when the electrolyte membrane is damaged And a separator.

As another example of a method by which the battery 10 can be modified, some embodiments of the battery may include, without limitation, pressure configured to regulate the pressure within a portion of the cell, including the anode compartment 25 and / Management system. Such a pressure management system may perform any suitable function, but in some embodiments it may be a halogen-containing solution in which the halogen is replaced with another species in the anode solution 35 (e. G., An excess of sodium halide, A complexing agent, a metal ion from the current collector 30, and the like) in the anode compartment.

In addition to the benefits of the battery 10 described above, the described battery may have a number of other beneficial properties. By way of example, being able to operate in a temperature range of less than about 150 캜, the battery 10 can operate at significantly lower operating temperatures than some conventional molten sodium rechargeable batteries. Thus, the described battery may require less energy to heat and / or dissipate heat from the battery when the battery is functioning, may be used or handled less dangerously, and may be more environmentally friendly . Additionally, some conventional sodium rechargeable batteries that operate at relatively high temperatures require relatively costly components (e.g., metal or ceramic components, glass encapsulation, and / or thermal expansion-matching components) , Some embodiments of the described battery may be made from a less expensive material (e.g., polymeric material, epoxy, epoxy and / or plastic mechanical sealing components, such as the O-ring 85 shown in FIG. 3, cap 90, Tube flange 92, etc.). Figure 3a shows that one compartment (e. G., Cathode compartment 15) is separated from the other compartment (e. G., Anode compartment 25 ) Of the battery 10 having a tubular design that is at least partially disposed within the battery 10.

As another example, some embodiments of the described battery 10 may be maintained at a suitable operating temperature through Joule heating by itself. As a result, relatively high efficiencies may be possible, since such cells may not require additional energy to maintain these cells at high operating temperatures.

As another example, some embodiments of the described battery 10 include some conventional competitive batteries (e.g., some Na / S batteries with a theoretical voltage of about 2.07 V and some Zn / S batteries with a theoretical voltage of about 1.85 V) (E.g., about 3.23 V to about 3.79 V), as compared to a Br ₂ battery. Additionally, some embodiments of the described battery may include some competitive batteries (e.g., some Na / S rechargeable batteries having a theoretical specific energy of about 755 Wh / kg or some normal (For example, about 987 Wh / kg for a NaBr / Br ₂ battery and about 581 Wh / kg for a NaI / I ₂ cell), compared to a Zn / Br ₂ rechargeable battery . Similarly, some embodiments of the described battery may include some conventional competitive batteries (e.g., some Na / S batteries having an actual specific energy of about 150 to about 240 Wh / kg and an actual specific energy of about 65 Wh / kg compared with some of the Zn / Br ₂ battery) having, for a relatively high actual specific energy (e. g., from about 330 to about 440. for some embodiments NaBr / Br ₂ cell mode).

As a result of the relatively high voltage and specific energy associated with some embodiments of the described battery 10, fewer such embodiments may be needed to achieve the same voltage and specific energy obtained by conventional competitive batteries. In this regard, using a smaller number of cells may reduce the amount of battery interconnect hardware and charge-conditioning circuitry required to achieve the target voltage and target specific energy. Thus, some embodiments of the described battery may reduce overall battery complexity and total cost through removal of the battery, interconnecting hardware, and charge conditioning circuitry. Additionally, as a result of the relatively high capacity and voltage of the battery, such a battery may be useful in a wide variety of articles, including, without limitation, grid-scale electric energy storage systems and electric vehicles.

As an example of another advantageous characteristic, some embodiments of the described battery 10 have a relatively long cycle life (e.g., about 4,000 cycles for some Na / S batteries and some Zn / Br ₂ batteries (About 5,000 deep cycles in some NaBr / Br ₂ battery embodiments, unlike about 2,000 in the case of some NaBr / Br ₂ battery embodiments). Additionally, since some embodiments of the described battery can make extensive use of sodium and halogen during cycling, the discharge / charge cycle of this embodiment may be relatively deep compared to some conventional batteries (e.g., about 70% A high SOC (charge state) and DOD (discharge depth) of about 80%).

As another example, some embodiments of the described battery 10 include high sodium ion mobility through the electrolyte membrane 40 (e.g., a fully dense NaSICON-type material on a porous support) and a relatively fast redox reaction rate (And hence the resulting power) due to the low temperature and intermediate temperatures described herein (e.g., at ambient temperature to about 150 ° C).

Hereinafter, in Fig. 13, a further embodiment of the battery 10 is illustrated. This embodiment includes a sodium ion conductive electrolyte membrane 40, for example a NaSICON membrane sold under the NaSELECT trademark by Ceramatech, Inc. of Salt Lake City, Utah. The battery 10 also includes a sodium-based cathode 20 comprising a sodium metal in the embodiment of FIG. The cathode is housed in a cathode compartment (15). Sodium ions are respectively transported from the cathode 20 to the anode compartment 25 through the sodium ion conductive electrolyte membrane 40. The current collector 30a may be used in the cathode compartment 15 as the case may be. Those of ordinary skill in the relevant art will recognize certain types of materials that may be used in the current collector 30a.

The anode compartment 25 comprises a current collector 30, which may be a carbon current collector, although other types of materials (e.g. metal) may be used. The liquid anolyte solution 35 is also contained in the anode compartment 25. In the embodiment of Figure 13, the solution comprises a NaBr / Br ₂ mixture in the solvent. Of course, other types of halogen / halide containing materials may be used.

In the embodiment of Figure 13, the cell 10 is comprised of a molten sodium anode and an aqueous or non-aqueous bromine cathode. This battery has a theoretical voltage of 3.79 V. Since the melting point of the Na metal is about 100 ° C, the battery can operate above 110 ° C, preferably above 120 ° C. Catholyte for this embodiment is formulated with an excess of sodium bromide with elemental bromine, Br ₃ ^- may be formed with a sodium halide such as poly. These species have a lower vapor pressure, but are electroactive similarly to bromine (although, of course, other types of halides may be used, although bromine is illustrated as a halide material).

The embodiment of FIG. 13 may have certain advantages. For example, one potential application for the present invention is the use of a battery in a large-scale secondary battery, for example, in a grid-scale energy storage system (ESS) and electric vehicle (EV) market. In addition, the film 40 may have a room temperature conductivity in the range of 5 x ^10-3 S / cm. In addition, NaSICON membranes can be completely insensitive to moisture and other conventional solvents (e.g., methanol).

With reference to FIG. 13, a further embodiment can be constructed in which the liquid anode solution 35 comprises additional species which form bromine and / or polybromide adducts such as bromide-amine adducts. The following are examples of tetramethylammonium bromide that act as complexing agents:

Br ₂ + tetramethylammonium bromide ↔ tetramethylammonium tribromide

In one embodiment, the membrane is a NaSICON tube that allows the battery system to be pressurized. Pressure can be used to maintain the bromine in solution form.

Hereinafter, in Fig. 14, another embodiment of the battery 10 is illustrated. This embodiment of the battery 10 is similar to that shown in Fig. However, in the embodiment of FIG. 14, the cell 10 avoids the production of bromine by using a metal current collector 30 which oxidizes to form the corresponding bromide. The following are non-limiting examples of cathode half-cell reactions:

Examples of complete cell reactions are:

This cell 10 relies on the oxidation of the pre-oxidation current collector 30 metal of bromide ion to bromine, resulting in the formation of non-volatile metal bromide. The voltages of these batteries may be 2.57, 2.61 and 2 volts for Cu, Ni and Zn, respectively. The battery may comprise a bromide or bromine electrode, a complexing agent, and an aqueous or non-aqueous solvent at 120 &lt; 0 &gt; C. The battery can have a stable NaSICON film under these conditions.

Hereinafter, in Fig. 15, a further embodiment of the battery 10 is illustrated. In the embodiment of FIG. 15, the battery 10 may comprise a solid sodium anode. However, as shown in Fig. 15, the battery 10 includes a sodium intercalated carbon anode 20a. The anode compartment 25 comprises an aqueous or non-aqueous bromine or bromide solution used as the liquid cathode solution 35. The anode liquid 60 is located adjacent to the film 40 (which may be a NaSICON film).

The cell 10 of FIG. 15 can be operated at ambient to 60 ° C., where elemental bromine can be effectively complexed such that free bromine can be reduced by more than 100-fold (eg, N-methyl-N- Methylmorpholinium bromide). Other complexing agents capable of effectively complexing bromine at ambient temperature can be used (MEMBr may be used in zinc-bromine systems). In one embodiment, the cell 10 utilizes a non-aqueous anode liquid 65 between the sodium intercalated carbon and the NaSICON film 40.

One particular embodiment of the battery 10 shown in Figure 15 uses bromine or bromide as the halogen / halide material in the anode compartment 25. NaSICON membranes and such aqueous or non-aqueous solvents are stable at ambient temperatures. The battery 10 is capable of reversible plating of Na and can have a bromine cathode. The battery can operate at least 25 reversible cycles at actual C-rate (C / 5) and actual discharge depth (DOD ≥ 50%).

Hereinafter, in Fig. 16, a further embodiment of the battery 10 is illustrated. This battery uses a Zn cathode 20b and a positive electrode (a current collector is used in the positive electrode compartment 25, but this characteristic is not shown in FIG. 16). The battery 10 uses a dense NaSICON film 40 that is sodium ion selective and water impermeable. The anode liquid 65 and the liquid positive electrode solution 35 are sodium bromide-based solutions and may not be a zinc bromide solution.

In this battery 10, the Zn anode 20b will be placed in an aqueous solution containing sodium bromide (or another alkali metal ion and a halide ion solution). The anode shown in this figure may be Zn or other metal. The liquid anode solution 35 (cathode solution) will be a solution of bromine / sodium bromide having a graphite current collector. During the discharge, Zn will oxidize to form zinc bromide, and sodium ions will be transported to the cathode current collector, where they will react with bromine to form sodium bromide. During charging, Zn will be re-deposited and bromine is regenerated. The advantages of this battery 10 compared to a microporous type battery are as follows:

(1) The composition of the anode liquid can be adjusted to enable reversible deposition of Zn. In fact, the anode liquid may be a mixture of NaBr and NaOH such that a zinc dendrite that results in loss of capacity can not be formed.

(2) Since the bromine from the catholyte will never contact the zinc metal, there is no self-discharge.

(3) Specific electrolyte chemistry may be used to avoid the need for flow of anode and cathode liquids.

(4) Other lower reducing potential elements (such as Mg) may be used that result in a higher voltage battery when a non-aqueous solvent is used.

The battery 10 of this embodiment will have a Zn anode in sodium bromide and / or sodium hydroxide solution in a NaSICON-based cell and will be capable of reversible deposition. Such NaSICON membranes in a battery will be stable at ambient temperature in the presence of a bromide / bromine / complexing agent / aqueous or non-aqueous solvent.

Battery 10 may be configured to have a reversible NaBr / Br ₂ cathodes operating at ambient temperature. Such a battery 10 may have at least 25 reversible cycles at actual C-rate (C / 5) and actual discharge depth (DOD ≥ 50%) of a stagnant battery having a Zn anode and a NaBr / Br ₂ cathode.

Example

The following examples are given to illustrate various embodiments, and aspects thereof, within the scope of the present invention. It is understood that the embodiments are given by way of example only, and that the following embodiments are not meant to be comprehensive or exhaustive of the many types of embodiments that may be made.

Example  One

For example, a molten sodium cathode 20, a platinum mesh current collector 30, an anode solution comprising 20 wt% NaI in formamide with a molar ratio of I ₂ to NaI of 1: 3 + 5 wt % &Lt; / RTI &gt; carbon. In this example, after operating for 2,000 minutes at a temperature up to about 120 &lt; 0 &gt; C, the cell had the performance characteristics shown in Fig. Specifically, it can be seen from FIG. 8 that the battery has a relatively large overcharge potential as well as a relatively noisy charging / discharging curve. In this regard, it is believed that these noise curves and overvoltages may have resulted from the use of formamide, because the formamide only dissolves NaI and does not dissolve the iodine to produce bubbles, Is less conductive than any other suitable solvent that may be present. Nevertheless, it can be seen from FIG. 8 that at least some embodiments of the NaI / NaI ₂ cell described are feasible.

Example  2

In a second example, a molten sodium cathode 20, a platinum mesh current collector 30, a NaSICON-type membrane having a current density of 5 mA / cm ² to 10 mA / cm ² , The battery 10 was set to include an anode solution containing more than 75% DMSO. In this example, after more than 150 hours of operation at temperatures up to about 120 캜, the cell had the performance characteristics shown in Fig. 9 (according to Battery Chemistry 1 described above). Specifically, from the performance characteristics of Fig. 9, it can be seen that the battery of this embodiment has a lower overvoltage than that of the battery of the preceding embodiment. In this regard, it is believed that the DMSO solution is more conductive than the formamide, thus providing a lower overvoltage to the cell. Further, in this experiment, it was clear that DMSO dissolves NaI and iodine. It is also believed that DMSO has a stable electrochemical window that allows the present cell to operate better than the cell of Example 1. Thus, from this example, DMSO appears to be a better solvent for use than formamide in at least some embodiments of the cell.

Example  3

As a third example, an electrolyte membrane 40 having a current density of about 3.65 mA / cm ² and a surface area roughly four times that of the membrane used in the first two embodiments, a molten sodium cathode 20, a platinum mesh current collector 30 ), And an anode solution 35 containing about 75 wt% of formamide with about 0.5 mole of I ₂ per mole of NaI and about 25 wt% or less of NaI. Additionally, an electrolyte membrane 40, a molten sodium cathode 20, a platinum mesh current collector 30, and an electrolyte membrane 40 having a current density of about 3.65 mA / cm ² and a surface area roughly four times that of the membrane used in the first two embodiments, The second large cell was set to include an anode solution 35 containing about 75 wt% of DMSO with about 0.5 mole of I ₂ per mole of NaI and about 25 wt% or less of NaI. These two cells were operated at a temperature up to about 120 &lt; 0 &gt; C for more than 120 hours with a discharge depth of about 20% of the cell effective capacity. The performance characteristics of the cell using the DMSO solvent are shown in Fig. 10 (according to Battery Chemistry 1 described above). The performance characteristics of the cells using formamide were similar. Figure 11 shows some performance characteristics for a DMSO cell when the cell operates at a discharge depth of 50% of the cell effective capacity according to Battery Chemistry 1 described above. In this regard, Fig. 11 shows the operational feasibility of a battery having such a relatively deep discharge cycle.

Example  4

For example, dissolved in the dimethylformamide solvent with the molten sodium anode 20, electrolyte layer 40 including NaSICON- type film having a current density of about 10 mA / cm ^2, and carbon was added NaI / I ₂ The battery 10 was set so as to include the positive electrode solution 35 containing the positive electrode solution 35. Then, the battery was operated at about 110 DEG C for more than 30 hours. Some performance characteristics of the test run of this experimental cell are shown in Figure 12 (according to Battery Chemistry 1 described above). In this connection, from Fig. 12, it can be seen that the voltage drop of the experimental cell is relatively large and there is some noise in the data. Fig. 12 shows the feasibility of a sodium-halogen based system using iodine.

Example  5

As an example of a battery chemistry 1 and a battery chemistry 2 case where the halogen is iodine, oxidation of a pH neutral sodium iodide solution near neutrality was studied using a standard electrochemical cyclic voltammetric (CV) method. Test set included the three platinum electrode (by one, one relative and one operation) contained in 0.2M NaI / 0.1MI ₂ aqueous solution. The test was performed at ambient temperature. During the test, the cell voltage was gradually increased and decreased with respect to the cell open circuit voltage, and the working electrode potential was measured using the reference electrode. In addition, the cell current generated by the operation and the reaction of the counter electrode was measured. Figure 17 shows a different process (indicated by an increase in current) that occurs during 500 mV / s (left) and 5 mV / s (right) working electrode potential scans for the reference. The first step occurring at 0.3 V during the positive anode (oxidation) scan was the oxidation of the following iodide to the triiodide following the reaction of Battery Chemistry 1 described above:

3NaI? NaI ₃ + 2Na ⁺ + 2 e ^-

The following oxidation peak at 0.8 V occurs due to the oxidation of the following triiodide to the molecular iodine following the reaction of Battery Chemistry 2 described above:

NaI ₃ → 3/2 I ₂ + Na ⁺ + e ^-

From this data it is easier to oxidize sodium iodide to triiodide, which, when coupled with molten Na, results in a higher ionization potential, which leads to higher voltage battery chemistry 2 (open circuit voltage of 3.15 V) Id will result in lower voltage battery chemistry 1 (2.8 V open circuit voltage) compared to oxidation to iodine.

Example  6

As an example of battery chemistry, a molten sodium cathode, an electrolyte membrane comprising a NaSICON-type membrane with a current density of approximately 8.8 mA / cm ² , and an anode solution comprising 35 wt.% NaI dissolved in NMF solvent (I ₂ No battery) was set. The cell was then operated at about 110 캜 for more than 24 hours. Some performance characteristics of the test operation of this experimental cell are shown in Fig. In this regard, FIG. 18 shows the first six cycles using constant current charging (rising voltage portion) followed by constant voltage charging at the initial high 3.25 voltage (flat voltage portion). This was sufficient to raise the charge OCV of the system above 3 V, which represents anode battery chemistry 2. The last cycle has a constant current, but maintains a high charge OCV, representing a high voltage battery chemistry 2.

Example  7

As an example, a molten sodium cathode, an electrolyte membrane comprising a NaSICON-type membrane with a current density of approximately 7.5 mA / cm ² , and an anode solution (without I ₂ ) containing 35 wt.% NaI dissolved in NMF solvent A 263 mAh battery was set to include. The cell was then operated at about 110 캜 for about 200 hours. Some performance characteristics of the test operation of this experimental cell are shown in Fig. In this regard, Figure 19 shows an initial cycle using constant voltage charging at a high voltage, which was sufficient to raise the charge OCV of the system for the remaining cycles to above 3 V representing anode battery chemistry 2.

Example  8

As an example, a molten sodium cathode, an electrolyte membrane comprising a NaSICON-type membrane with a current density of approximately 3.8 mA / cm ² , and an anode solution (without I ₂ ) containing 35 wt.% NaI dissolved in NMF solvent A 263 mAh battery was set to include. The cell was then operated at about 110 캜 over 3 charge / discharge cycles. Some performance characteristics of the test operation of this experimental cell are shown in Fig. In this connection, it can be seen from FIG. 20 that the higher partial voltage charging increases the coulomb efficiency and the transportable capacity.

Example  9

As an example, a molten sodium cathode, an electrolyte membrane comprising a NaSICON-type membrane with a current density of approximately 8.3 mA / cm ² , and 7M I ₂ (pre-charged with excess iodine) dissolved in NMF solvent or DMSO solvent and Two cells were set up to contain the positive electrode solution containing 3M NaI. Then, the batteries were discharged at about 120 캜. The discharge characteristics of the test operation of these experimental cells are shown in Fig. In this regard, it can be seen from FIG. 21 that in NMF, battery chemistry 1 (triiodide to iodide) occurs whereas in DMSO the combination of battery chemistries 1 and 2 (from iodine to triiodide to iodide) I can see the rise. This result indicates that the solvent used to dissolve NaI and I ₂ affects the battery chemistry that occurs during discharge.

Thus, it can be seen from the above-mentioned embodiments that a Na-iodine battery can be realized which dissolves sodium iodide and dissolves (at least partially) iodine using DMSO or NMF as solvent. This system is capable of a deep discharge of about 50% of the effective capacity of the NaI / iodine cathode and up to about 70% of the effective capacity of the NaI / iodine cathode, if possible, have. In some embodiments, the Pt cathode may be replaced with a cheaper cathode such as graphite, hard carbon or metals such as manganese, molybdenum, tungsten, titanium, tantalum and other valve metals. The film used in the battery may be a NaSICON film, and may have a current density of 10 mA / cm ² or more.

The batteries (batteries) described herein can have significant advantages over other types of batteries. For example, as noted above, many types of known sodium rechargeable batteries must be operated at high temperatures, for example, above 250 ° C or even above 270 ° C. However, as mentioned herein, this embodiment can be operated at temperatures below 250 ° C. In fact, some embodiments can operate at ambient temperature, temperatures below about 60 占 폚, below about 150 占 폚, below 200 占 폚, below 180 占 폚, and the like. These temperature ranges for the battery can provide significant benefits because resources need not be allocated to heat the battery to very high temperatures (e.g., 270 [deg.] C).

In addition, some embodiments of the present invention may use NaSICON as a separator in place of sodium beta "- alumina ceramic material. NaSICON has certain advantages over sodium beta" - alumina ceramic because it is compatible with water and other solvents. In addition, NaSICON can separate the two sides of the cell so that reactants on one side of the membrane can be optimized on each side without fear of contamination / interfering reactants on the other side of the membrane.

All patent applications and patents listed herein are expressly incorporated herein by reference.

Embodiments of the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The described embodiments and examples are merely exemplary in all respects and should not be construed as limiting. Accordingly, the scope of the invention is indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims (15)

Wherein the cathode is electrochemically oxidized during discharging to release sodium ions and electrochemically reducing sodium ions during refill to form a sodium metal cathode, wherein the cathode compartment comprises a cathode comprising sodium;
A positive electrode compartment comprising a current collector disposed in a liquid positive electrode solution comprising at least one of a halogen and a halide,
NaX ₃ + 2e ^- 3NaX
3X ₂ + 2Na ⁺ + 2e ^- 2NaX ₃
The anode compartment being configured to perform at least one reaction in the anode compartment selected from the anode compartment; And
A sodium ion conductive electrolyte membrane separating the cathode from the liquid anode solution
&Lt; / RTI &gt; The secondary battery according to claim 1, wherein the cathode comprises a molten sodium metal. The secondary battery according to claim 1, wherein the secondary battery operates when the temperature of the cathode is less than about 150 캜. 4. The secondary battery of claim 3, wherein the temperature of the cathode is also greater than about 100 &lt; 0 &gt; C. The secondary battery according to claim 1, wherein the electrolyte membrane comprises a NaSICON-type material. 6. The secondary battery of claim 5, wherein the NaSICON-type material comprises a composite membrane having a porous layer and a dense functional coating layer. The secondary battery according to claim 1, wherein the liquid anode solution comprises a solvent selected so that the reaction in the anode compartment of 3X ₂ + 2Na ⁺ + 2e ^- 2NaX ₃ predominates. The secondary battery according to claim 1, wherein the liquid anode solution comprises a dimethyl sulfoxide solvent. The secondary battery according to claim 1, wherein the liquid anode solution comprises an N-methyl formamide solvent. The secondary battery according to claim 1, wherein the liquid anode solution comprises a compound selected from NaBr, NaI and NaCl. The secondary battery according to claim 1, wherein the liquid anode solution comprises at least one of an amount of sodium halide and an elemental halogen in an amount sufficient to form a sodium polyhalide when the secondary battery operates. The secondary battery according to claim 1, wherein the liquid anolyte solution comprises a complexing agent capable of forming a complex with at least one of halogen, sodium halide and polyhalide in the liquid anolyte solution. The secondary battery of claim 1, wherein the complexing agent comprises a tetramethylammonium halide compound. The method of claim 1 wherein the current collector comprises a material selected from the group consisting of graphite, hard carbon, manganese, molybdenum, tungsten, titanium, tantalum, copper, nickel, Lt; / RTI &gt; The method according to claim 1,
A first reservoir in fluid communication with the anode compartment; And
A first pumping mechanism configured to flow liquid anode solution from the first reservoir into the anode compartment and through the collector,
Further comprising a secondary battery.

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