NEGATIVE ELECTRODE MATERIAL FOR SODIUM SECONDARY BATTERY, ELECTRODE FOR SODIUM SECONDARY BATTERY, AND SODIUM SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a sodium secondary battery having a high charge-discharge capacity, an electrode for a sodium secondary battery suitable for the secondary battery, and a negative electrode material for a sodium secondary battery suitable for the electrode.SOLUTION: A negative electrode material for a sodium secondary battery contains an amorphous carbon material capable of being doped and de-doped with sodium ions. The amorphous carbon material shows one of a first peak indicating the maximum heat generation and a second peak indicating the second greatest heat generation in the temperature range of 400 to 615°C in a thermogravimetric/differential thermal analysis at temperatures of 400°C or higher, and the other peak in the temperature range of 620 to 800°C. An electrode for a sodium secondary battery contains the negative electrode material, and a sodium secondary battery includes the electrode as a negative electrode.