NEGATIVE ELECTRODE MATERIAL FOR LITHIUM-ION SECONDARY BATTERY AND METHOD FOR PRODUCING NEGATIVE ELECTRODE MATERIAL FOR LITHIUM-ION SECONDARY BATTERY

A negative electrode material for a lithium-ion secondary battery is disclosed which contains a mass of graphite particle spherical aggregates in which a plurality of flat graphite particles are aggregated. The mass of the graphite particle spherical aggregates has an average circularity, D/D, and a crystallite size Lc (004) within a predetermined range, and the proportion of the graphite particle spherical aggregates in which the largest flat graphite particle observed on the outermost surface has a circle equivalent diameter of 2 μm to 12 μm in graphite particle spherical aggregates having a circle equivalent diameter of 10 μm or more when observed by SEM is 80% or more.