NEGATIVE ELECTRODE ACTIVE MATERIAL FOR LITHIUM ION SECONDARY BATTERY

Provided is a negative electrode active material for a lithium-ion secondary battery, comprising SiO x that has an intensity ratio A 1 /A 2 of 0.1 or less in spectra measured by a Fourier transform infrared spectrometer after subjecting the SiO x to evacuation treatment at 200°C, given that A 1 designates an intensity of a silanol group-derived peak which appears around 3400 to 3800 cm -1 , and A 2 designates an intensity of a siloxane bond-derived peak which appears around 1000 to 1200 cm -1 . It is preferred that x in the SiO x satisfies x