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 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.