To improve charge-discharge cycle characteristics of an alkali metal sulfur secondary battery.

The alkali metal sulfur secondary battery includes a positive electrode 20 containing porus carbonate material with nitrogen doped and sulfur, a negative electrode 16 containing lithium as an alkali metal element, and a nonaqueous electrolyte interposed between the positive electrode 20 and negative electrode 16 and conducting lithium ions. A ratio of a nitrogen atom and carbonate atom N/C of the nitrogen-doped porous carbonate material is preferably 0.05-0.3, and a BET specific surface area is preferably 300-1,200 m2/g. In this battery, polysulfide ions generated in charge-discharge reaction is likely to be adsorbed in the porous carbonate material contained in the positive electrode, and a sulfur composition hardly transfers to the negative electrode.

COPYRIGHT: (C)2010,JPO&INPIT