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: 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: 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-type 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.