Composite particle, method for producing the same, and applications thereof

A composite particle comprising a particle comprising a carbon material and silicon, and a coating layer comprising carbon and oxygen on the surface of the particle, wherein

• the composite particle has a true density according to dry density measurement using helium gas of 1.80 g/cm3 or more and 1.99 g/cm3 or less;
• in the Raman spectrum of the composite particle,
• a peak is present at 450 to 495 cm−1, and
• when the intensity of the peak is defined as ISi and the intensity of the G band (peak intensity in the vicinity of 1580 cm−1) is defined as IG, ISi/IG is 1.3 or less;
• and
• when the ratios of the number of atoms of Si, O, and C according to the Narrow spectrum of X-ray photoelectron spectroscopy for the composite particle are defined as ASi, AO, and AC, respectively, and when, among the Si species ratios according to Si2p spectral state analysis, the ratios of SiO2 and SiO are defined as BSiO2 and BSiO, respectively,
• ASi is 0.05 or more, and
• at least one of the following expressions (1) and (2) is satisfied:
• Y
• ≥
• 0.75
• (
• 1
• )
• Y
• ≥
• -
• 0.32
• ⁢
• X
• +
• 0.81
• (
• 2
• )
• wherein in expressions (1) and (2), X=ISi/IG and Y=AC/(AC+ASi×(BSiO2+BSiO)).