Method for producing negative electrode active material particle

A method for producing a negative electrode active material particle including a silicon compound particle, comprising the steps of:

• preparing a silicon compound particle containing a silicon compound that contains oxygen;
• inserting Li into the silicon compound particle;
• and
• heating, while stirring, the Li-inserted silicon compound particle in a furnace to produce a negative electrode active material particle, wherein at least part of Si constituting the silicon compound particle after the heating is present in at least one state selected from an oxide of Si2+ to Si3+ containing no Li, and a compound containing Li and Si2+ to Si3+,
• wherein the silicon compound particle has a peak or shoulder peak in an energy range from 1844 eV to 1846.5 eV in a XANES region of a Si K-edge in an X-ray absorption spectrum obtained when an X-ray absorption fine structure analysis is performed, and
• wherein as the silicon compound particle is charged with electricity in a larger amount in an electricity charging process, the peak or shoulder peak appearing in the energy range from 1844 eV to 1846.5 eV in the XANES region of the Si K-edge has a higher intensity.