METHOD FOR OPERATING SODIUM-SULFUR BATTERY

摘要

PROBLEM TO BE SOLVED: To actualize an operating method for allowing the achievement of a longer lasting sodium-sulfur battery. SOLUTION: In the sodium-sulfur battery, sulfur as a positive-electrode active material and sodium as a negative-electrode active material are disposed with a sodium-ion conductive solid electrolyte interposed between them and a battery reaction produces sodium polysulfide in the positive-electrode active material. This method for operating the battery includes a process for keeping battery temperature during operation not lower than the melting point of sodium polysulfide expressed by Na2 S5 and not higher than the melting point of sodium polysulfide expressed by Na2 S4 .