Porous Silicon Negative Electrode Material, Silicon Negative Electrode Sheet, and Lithium-Ion Battery

Disclosed is a porous silicon negative electrode material, comprising a sparse-silicon inner core, and a transition ring, a dense-silicon ring and a carbon coating layer which are sequentially coated on the surface of the sparse-silicon inner core. In the sparse-silicon inner core, the transition ring and the dense-silicon ring, the porosity sequentially decreases, and the silicon density sequentially increases. Further disclosed are a negative electrode sheet and a lithium-ion battery which are prepared from the described porous silicon negative electrode material. The porous silicon negative electrode material of the present disclosure effectively reduces the expansion and contraction stress of the electrode material during cycle and slows down the capacity attenuation, and thus the battery capacity retention rate is high, and the cycle performance is stable.