Abstract: An intermediate temperature sodium-halogen secondary cell that includes a negative electrode compartment housing a negative, molten sodium-based electrode and a positive electrode compartment housing a current collector disposed in a highly conductive molten positive electrolyte. A sodium halide (NaX) positive electrode is disposed in a molten positive electrolyte comprising one or more AlX3 salts, wherein X may be the same or different halogen selected from Cl, Br, and I, wherein the ratio of NaX to AlX3 is greater than or equal to one. A sodium ion conductive solid electrolyte membrane separates the molten sodium negative electrode from the molten positive electrolyte. The secondary cell operates at a temperature in the range from about 80° C. to 210° C.

Abstract: The present invention provides a sodium-aluminum secondary cell. The cell includes a sodium metal negative electrode, a positive electrode compartment that includes an aluminum positive electrode disposed in a positive electrolyte mixture of NaAl2X7 and NaAlX4, where X is a halogen atom or mixture of different halogen atoms selected from chlorine, bromine, and iodine, and a sodium ion conductive electrolyte membrane that separates the negative electrode from the positive electrolyte. In such cases, the electrolyte membrane can include any suitable material, including, without limitation, a NaSICON-type membrane. Generally, when the cell functions, both the sodium negative electrode and the positive electrolyte are molten and in contact with the electrolyte membrane. Additionally, the cell is functional at an operating temperature between about 100° C. and about 200° C.

Abstract: The present invention provides a secondary cell having a negative electrode compartment and a positive electrode compartment, which are separated by an alkali ion conductive electrolyte membrane. An alkali metal negative electrode disposed in the negative electrode compartment oxidizes to release alkali ions as the cell discharges and reduces the alkali ions to alkali metal during recharge. The positive electrode compartment includes a positive electrode contacting a positive electrode solution that includes an alkali metal compound and a metal halide. The alkali metal compound can be selected from an alkali halide and an alkali pseudo-halide. During discharge, the metal ion reduces to form metal plating on the positive electrode. As the cell charges, the metal plating oxidizes to strip the metal plating to form metal halide or pseudo halide or corresponding metal complex.

Abstract: The present invention provides a molten sodium secondary cell. In some cases, the secondary cell includes a sodium metal negative electrode, a positive electrode compartment that includes a positive electrode disposed in a molten positive electrolyte comprising Na—FSA (sodium-bis(fluorosulonyl)amide), and a sodium ion conductive electrolyte membrane that separates the negative electrode from the positive electrolyte. One disclosed example of electrolyte membrane material includes, without limitation, a NaSICON-type membrane. The positive electrode includes a sodium intercalation electrode. Non-limiting examples of the sodium intercalation electrode include NaxMnO2, NaxCrO2, NaxNiO, and NaxFey(PO4)z. The cell is functional at an operating temperature between about 100° C. and about 150° C., and preferably between about 110° C. and about 130° C.

Abstract: The present invention provides a molten sodium secondary cell. In some cases, the secondary cell includes a sodium metal negative electrode, a positive electrode compartment that includes a positive electrode disposed in a molten positive electrolyte comprising Na-FSA (sodium-bis(fluorosulonyl)amide), and a sodium ion conductive electrolyte membrane that separates the negative electrode from the positive electrolyte. One disclosed example of electrolyte membrane material includes, without limitation, a NaSICON-type membrane. Non-limiting examples of the positive electrode include Ni, Zn, Cu, or Fe. The cell is functional at an operating temperature between about 100° C. and about 150° C., and preferably between about 110° C. and about 130° C.

Abstract: An additive that is added to the NaAlX4 electrolyte for use in a ZEBRA battery (or other similar battery). This additive has a moiety with a partial positive charge (?+) that attracts the negative charge of the [AlX4]? moiety and weakens the ionic bond between the Na+ and [AlX4]? moieties, thereby freeing some Na+ ions to transport (move). By using a suitable NaAlX4 electrolyte additive, the battery may be operated at much lower temperatures than are typical of ZEBRA batteries (such as, for example, at temperatures between 150 and 200° C.). Additionally, the additive also lowers the viscosity of the electrolyte solution and improves sodium conductivity. Non-limiting examples of the additive SOCl2, SO2, dimethyl sulfoxide (DMSO, CH3SOCH3), CH3S(O)Cl, SO2Cl2. A further advantage of using this additive is that it allows the use of a NaSICON membrane in a ZEBRA-type battery at lower temperatures compared to a typical ZEBRA battery.

Abstract: An intermediate temperature molten sodium-metal halide rechargeable battery utilizes a molten eutectic mixture of sodium haloaluminate salts having a relatively low melting point that enables the battery to operate at substantially lower temperature compared to the traditional ZEBRA battery system and utilize a highly conductive NaSICON solid electrolyte membrane. The positive electrode comprises a mixture of NaX and MX, where X is a halogen selected from Cl, Br and I and M is a metal selected Ni, Fe, and Zn. The positive electrode is disposed in a mixed molten salt positive electrolyte comprising at least two salts that can be represented by the formula NaAlX?4-?X??, where 0<?<4, wherein X? and X? are different halogens selected from Cl, Br and I. The positive electrode may include additional NaX added in a molar ratio ranging from 1:1 to 3:1 of NaX:NaAlX?4-?X??.

Abstract: The present invention provides a sodium-aluminum secondary cell. The cell includes a sodium metal negative electrode, a positive electrode compartment that includes an aluminum positive electrode disposed in a positive electrolyte mixture of NaAl2X7 and NaAlX4, where X is a halogen atom or mixture of different halogen atoms selected from chlorine, bromine, and iodine, and a sodium ion conductive electrolyte membrane that separates the negative electrode from the positive electrolyte. In such cases, the electrolyte membrane can include any suitable material, including, without limitation, a NaSICON-type membrane. Generally, when the cell functions, both the sodium negative electrode and the positive electrolyte are molten and in contact with the electrolyte membrane. Additionally, the cell is functional at an operating temperature between about 100° C. and about 200° C.

Abstract: The present invention provides an electrochemical cell having an negative electrode compartment and a positive electrode compartment. A solid alkali ion conductive electrolyte membrane is positioned between the negative electrode compartment and the positive electrode compartment. A catholyte solution in the positive electrode compartment includes a halide ion or pseudohalide ion concentration greater than 3M, which provides degradation protection to the alkali ion conductive electrolyte membrane. The halide ion or pseudohalide ion is selected from chloride, bromide, iodide, azide, thiocyanate, and cyanide. In some embodiments, the electrochemical cell is a molten sodium rechargeable cell which functions at an operating temperature between about 100° C. and about 150° C.

Abstract: A sodium-halogen secondary cell that includes a negative electrode compartment housing a negative, sodium-based electrode and a positive electrode compartment housing a current collector disposed in a liquid positive electrode solution. The liquid positive electrode solution includes a halogen and/or a halide. The cell includes a sodium ion conductive electrolyte membrane that separates the negative electrode from the liquid positive electrode solution. Although in some cases, the negative sodium-based electrode is molten during cell operation, in other cases, the negative electrode includes a sodium electrode or a sodium intercalation carbon electrode that is solid during operation.

Abstract: An intermediate temperature sodium-halogen secondary cell that includes a negative electrode compartment housing a negative, molten sodium-based electrode and a positive electrode compartment housing a current collector disposed in a highly conductive molten positive electrolyte. A sodium halide (NaX) positive electrode is disposed in a molten positive electrolyte comprising one or more AlX3 salts, wherein X may be the same or different halogen selected from Cl, Br, and I, wherein the ratio of NaX to AlX3 is greater than or equal to one. A sodium ion conductive solid electrolyte membrane separates the molten sodium negative electrode from the molten positive electrolyte. The secondary cell operates at a temperature in the range from about 80° C. to 210° C.

Abstract: An intermediate temperature molten sodium-metal halide rechargeable battery utilizes a molten eutectic mixture of sodium haloaluminate salts having a relatively low melting point that enables the battery to operate at substantially lower temperature compared to the traditional ZEBRA battery system and utilize a highly conductive NaSICON solid electrolyte membrane. The positive electrode comprises a mixture of NaX and MX, where X is a halogen selected from Cl, Br and I and M is a metal selected Ni, Fe, and Zn. The positive electrode is disposed in a mixed molten salt positive electrolyte comprising at least two salts that can be represented by the formula NaAlX?4-?X??, where 0<?<4, wherein X? and X? are different halogens selected from Cl, Br and I. The positive electrode may include additional NaX added in a molar ratio ranging from 1:1 to 3:1 of NaX:NaAlX?4-?X??.

Abstract: The present invention provides a molten sodium secondary cell. In some cases, the secondary cell includes a sodium metal negative electrode, a positive electrode compartment that includes a positive electrode disposed in a liquid positive electrode solution, and a sodium ion conductive electrolyte membrane that separates the negative electrode from the positive electrode solution. In such cases, the electrolyte membrane can comprise any suitable material, including, without limitation, a NaSICON membrane. Furthermore, in such cases, the liquid positive electrode solution can comprise any suitable positive electrode solution, including, but not limited to, an aqueous sodium hydroxide solution. Generally, when the cell functions, the sodium negative electrode is molten and in contact with the electrolyte membrane. Additionally, the cell is functional at an operating temperature between about 100° C. and about 170° C. Indeed, in some instances, the molten sodium secondary cell is functional between about 110° C.

Abstract: A sodium-halogen secondary cell that includes a negative electrode compartment housing a negative, sodium-based electrode and a positive electrode compartment housing a current collector disposed in a liquid positive electrode solution. The liquid positive electrode solution includes a halogen and/or a halide. The cell includes a sodium ion conductive electrolyte membrane that separates the negative electrode from the liquid positive electrode solution. Although in some cases, the negative sodium-based electrode is molten during cell operation, in other cases, the negative electrode includes a sodium electrode or a sodium intercalation carbon electrode that is solid during operation.

Abstract: An additive that is added to the NaAlX4 electrolyte for use in a ZEBRA battery (or other similar battery). This additive has a moiety with a partial positive charge (?+) that attracts the negative charge of the [AlX4]? moiety and weakens the ionic bond between the Na+ and [AlX4]? moieties, thereby freeing some Na+ ions to transport (move). By using a suitable NaAlX4 electrolyte additive, the battery may be operated at much lower temperatures than are typical of ZEBRA batteries (such as, for example, at temperatures between 150 and 200° C.). Additionally, the additive also lowers the viscosity of the electrolyte solution and improves sodium conductivity. Non-limiting examples of the additive SOCl2, SO2, dimethyl sulfoxide (DMSO, CH3SOCH3), CH3S(O)Cl, SO2Cl2. A further advantage of using this additive is that it allows the use of a NaSICON membrane in a ZEBRA-type battery at lower temperatures compared to a typical ZEBRA battery.

Abstract: The present invention provides a molten sodium secondary cell. In some cases, the secondary cell includes a sodium metal negative electrode, a positive electrode compartment that includes a positive electrode disposed in a molten positive electrolyte comprising Na-FSA (sodium-bis(fluorosulonyl)amide), and a sodium ion conductive electrolyte membrane that separates the negative electrode from the positive electrolyte. One disclosed example of electrolyte membrane material includes, without limitation, a NaSICON-type membrane. Non-limiting examples of the positive electrode include Ni, Zn, Cu, or Fe. The cell is functional at an operating temperature between about 100° C. and about 150° C., and preferably between about 110° C. and about 130° C.

Abstract: The present invention provides a molten sodium secondary cell. In some cases, the secondary cell includes a sodium metal negative electrode, a positive electrode compartment that includes a positive electrode disposed in a molten positive electrolyte comprising Na—FSA (sodium-bis(fluorosulonyl)amide), and a sodium ion conductive electrolyte membrane that separates the negative electrode from the positive electrolyte. One disclosed example of electrolyte membrane material includes, without limitation, a NaSICON-type membrane. The positive electrode includes a sodium intercalation electrode. Non-limiting examples of the sodium intercalation electrode include NaxMnO2, NaxCrO2, NaxNiO, and NaxFey(PO4)z. The cell is functional at an operating temperature between about 100° C. and about 150° C., and preferably between about 110° C. and about 130° C.

Abstract: The present invention provides an electrochemical cell having an negative electrode compartment and a positive electrode compartment. A solid alkali ion conductive electrolyte membrane is positioned between the negative electrode compartment and the positive electrode compartment. A catholyte solution in the positive electrode compartment includes a halide ion or pseudohalide ion concentration greater than 3M, which provides degradation protection to the alkali ion conductive electrolyte membrane. The halide ion or pseudohalide ion is selected from chloride, bromide, iodide, azide, thiocyanate, and cyanide. In some embodiments, the electrochemical cell is a molten sodium rechargeable cell which functions at an operating temperature between about 100° C. and about 150° C.

Abstract: A sodium-halogen secondary cell that includes a negative electrode compartment housing a negative, sodium-based electrode and a positive electrode compartment housing a current collector disposed in a liquid positive electrode solution. The liquid positive electrode solution includes a halogen and/or a halide. The cell includes a sodium ion conductive electrolyte membrane that separates the negative electrode from the liquid positive electrode solution. Although in some cases, the negative sodium-based electrode is molten during cell operation, in other cases, the negative electrode includes a sodium electrode or a sodium intercalation carbon electrode that is solid during operation.

Abstract: The present invention provides a secondary cell having a negative electrode compartment and a positive electrode compartment, which are separated by an alkali ion conductive electrolyte membrane. An alkali metal negative electrode disposed in the negative electrode compartment oxidizes to release alkali ions as the cell discharges and reduces the alkali ions to alkali metal during recharge. The positive electrode compartment includes a positive electrode contacting a positive electrode solution that includes an alkali metal compound and a metal halide. The alkali metal compound can be selected from an alkali halide and an alkali pseudo-halide. During discharge, the metal ion reduces to form metal plating on the positive electrode. As the cell charges, the metal plating oxidizes to strip the metal plating to form metal halide or pseudo halide or corresponding metal complex.