Patent ID: 8334069

Claim:
An anode active material comprising silicon (Si), boron (B), carbon (C), and one or more of metal elements selected from the group consisting of cobalt (Co), titanium (Ti) and iron (Fe), wherein, a boron content is from and including 4.9 mass % to 19.8 mass %, a carbon content is from and including 4.9 mass % to 19.8 mass %, a total of the boron content and the carbon content is from and including 9.8 mass % to 29.8 mass %, a ratio of a silicon content to the total of the silicon content and a content of the metal element (Si/(Si+M)) is from and including 70 mass % to 95 mass %, and a reaction phase whose half-width of a diffraction peak obtained by X-ray diffraction is 1 degree or more is included and the anode active material is capable of reacting with an electrode reactant.