Anode active material, alkaline storage battery, and method for producing anode active material

An anode active material to be used in an alkaline storage battery,

• the anode active material comprising:
• a base material containing Ti and Cr, and including a BCC structure as a metastable phase;
• and
• a coating layer that coats the base material, and has a composition of TixNi (1≤x≤2);
• wherein
• the total proportion of Ti and Cr with respect to all metals configuring the base material is 90 at % or more,
• and a proportion of V in the base material is less than 10 at %,
• an oxide film is present in an interface between the coating layer and the base material;
• and
• when a maximum oxygen concentration CMAX (at %) of the oxide film near the interface, and a position P1 where the CMAX is obtained, are determined by Auger electron spectroscopy, and when 1/2CMAX designates a half value of the CMAX, PA designates a position where the 1/2CMAX is obtained in a region closer to the coating layer side than the P1, PB designates a position where the 1/2CMAX is obtained in a region closer to the base material side than the position P1, and when a distance from the P1 to the PA is regarded as a first thickness TA (nm) of the oxide film, a distance from the P1 to the PB is regarded as a second thickness TB (nm) of the oxide film, a distance from the PA to the PB is regarded as a thickness T (nm) of the oxide film, and a measurement interval in a depth direction is regarded as DI (nm),
• the anode active material satisfies at least one of:
• (i) a rate of the TA with respect to the TB, which is TA/TB is 1.50 or more;
• (ii) a difference between the TA and the TB, which is TA-TB is larger than the Dr;
• and
• (iii) a rate of the CMAX with respect to the T, which is CMAX/T is 0.035 or less;
• the thickness T of the oxide film is 200 nm or more;
• and
• the thickness of the coating layer is 100 nm or more and 2000 nm or less.