NEGATIVE ELECTRODE ACTIVE MATERIAL FOR SODIUM ION BATTERY, SODIUM ION BATTERY, AND METHOD FOR PRODUCING NEGATIVE ELECTRODE ACTIVE MATERIAL FOR SODIUM ION BATTERY

摘要

PROBLEM TO BE SOLVED: To provide a negative electrode active material for a sodium ion battery, which is excellent in charge/discharge efficiency.SOLUTION: The present invention provides a negative electrode active material for a sodium ion battery, which includes a negative electrode active substance material and a carbon material, the negative electrode active substance material being a compound having an aromatic ring structure and two or more COOX groups (X represents Li or Na) coupled to a terminal of the aromatic ring structure. The carbon material has interlayer distance d002 of 3.5 or less, or a D/G ratio determined by Raman spectrometry of 0.80 or less.