NEGATIVE ELECTRODE ACTIVE MATERIAL, MIXED NEGATIVE ELECTRODE ACTIVE MATERIAL, AQUEOUS NEGATIVE ELECTRODE SLURRY COMPOSITION, AND METHOD FOR PRODUCING NEGATIVE ELECTRODE ACTIVE MATERIAL

A negative electrode active material for a non-aqueous electrolyte secondary battery, containing negative electrode active material particles, including silicon compound particles each containing a silicon compound (SiO: 0.5≤x≤1.6) and at least one or more of LiSiOand LiSiO, the material includes a phosphate, the negative electrode active material particles each have a surface containing lithium element, and a ratio m/msatisfies 0.02≤m/m≤3, where mrepresents a molar quantity of the lithium element and contained per unit mass of the particles, and mrepresents a molar quantity of phosphorus element contained per unit mass of the particles. Thereby, a negative electrode active material is capable of stabilizing an aqueous negative electrode slurry prepared in producing a negative electrode of a secondary battery, and capable of improving initial charge-discharge characteristics when the negative electrode active material is used for a secondary battery.