Negative electrode active material, negative electrode, and battery

A negative electrode active material, comprising a plurality of alloy particles, wherein

• a chemical composition of the alloy particles contains:
• 0.50 to 3.00 mass % of oxygen;
• and
• alloy elements containing:
• in atomic composition percentage excluding the oxygen and carbon, Sn:
• 13.0 to 40.0 at % and Si:
• 6.0 to 40.0 at %, with a balance being Cu and impurities, wherein
• a structure of the alloy particles includes:
• one or more types selected from a group consisting of a phase having a D03 structure in Strukturbericht notation and having a Si content of 0 to 5.0 at %, and a δ phase having a Si content of 0 to 5.0 at %;
• one or more types selected from a group consisting of an ε phase having a Si content of 0 to 5.0 at % and an η′ phase having a Si content of 0 to 5.0 at %;
• and
• a SiOx phase (x=0.50 to 1.70), wherein
• the alloy particles have a peak having a maximum diffraction integrated intensity in an X-ray diffraction profile, in a range of 42.0 to 44.0 degrees of diffraction angle 2θ, and the peak has a half-value width of 0.15 to 2.50 degrees, and wherein
• in the structure of the alloy particles,
• the SiOx phase (x=0.50 to 1.70) has a volume fraction of 5.0 to 60.0%, and
• the η′ phase has a volume fraction of 0 to 60.0%.