| 摘要 |
PROBLEM TO BE SOLVED: To provide a negative electrode active material including nano silicon which exhibits a high capacity-keeping rate.SOLUTION: A negative electrode active material comprises nano silicon. As to the nano silicon, a content of crystal silicon calculated from a peak area ratio in a case of performing, by Gaussian distribution approximation, a peak separation of a silicon diffraction peak arising near 2&thetas;=28.4 degrees in XRD spectra measured with Cu Kα rays is 40% or less to all of silicon. Further, in the negative electrode active material, a content of oxygen included therein is 30 mass% or less. A power storage device comprises a negative electrode including the negative electrode active material. The negative electrode active material is produced by performing a thermal treatment on a layered polysilane having a structure composed of a chain of six-membered rings of silicon atoms, and expressed by the following compositional formula: (SiH). |
