The invention relates to a multi-element gradient composite high-first-effect
lithium battery negative
electrode material and a preparation method thereof. The negative
electrode material is of a multi-layer core-shell structure, and comprises an inner core, a buffer layer and an outer layer. The inner core and the buffer layer of the negative
electrode material are
silicon-
oxygen compounds, and the outer layer is a
carbon coating layer. The inner core and the buffer layer further contain
lithium salt and
magnesium salt, and the concentration of the
magnesium salt is increased progressively from the inner core to the buffer layer to form gradient distribution. There is more
lithium salt in the core of the negative
electrode material, so that a large amount of
active oxygen can be consumed,the initial coulombic efficiency of the material is effectively improved, and meanwhile, the
ion conductivity of the material is improved. There is more
magnesium silicate in the buffer layer, so that the initial charge-
discharge efficiency of the material is further improved, meanwhile, the
magnesium silicate forms a high-strength protective layer, the
structural stability of the material is enhanced, and the cycle performance of the material is improved.