NEGATIVE-ELECTRODE ACTIVE MATERIAL FOR SODIUM-ION BATTERY, AND SODIUM-ION BATTERY

The problem of the present invention is to provide an anode active material for a sodium ion battery, which may intend to improve safety of the battery. The present invention solves the problem by providing an anode active material for a sodium ion battery comprising an MNbOphase (M is at least one kind of H, Li, Na and K) belonging to an orthorhombic crystal.