The invention relates to the technical field of battery negative
electrode materials, and provides a silica negative
electrode material and a
lithium ion battery. The silica negative
electrode material has a core-shell structure and comprises an inner core, a middle layer
coating the surface of the inner core and an outer shell layer
coating the surface of the middle layer; the material of the inner core comprises
amorphous silicon oxide and
silicon microcrystals, and the sizes of the
silicon microcrystals are increased in a gradient manner along the direction from the center of the inner core to the
surface layer of the inner core; the middle layer is made of
silicon carbide; and the outer shell layer comprises a
carbon layer. The negative electrode core material with the characteristics can guide huge
volume expansion stress generated in a
lithium embedding process to be released outwards through silicon microcrystals which are distributed in an
amorphous silicon oxide main body material and have gradually changed sizes, so that
volume expansion of the silicon-based negative
electrode material is inhibited, and irreversible capacity increase caused by
volume expansion is reduced; therefore, the cycle life of the silicon-based negative
electrode material is effectively prolonged.