Facile preparation of silicon/carbon composite with porous architecture for advanced lithium-ion battery anode

Silicon is a potential anode material for Li battery due to its high theoretical specific capacity (4200 mAh g⁻¹). However, Si is hampered for practical application in Li-battery due to its enormous volume alternation causing instability. Herein, we demonstrated a novel carbon-coated porous structure (C@void/Si-G) synthesized by uniformly wrapping Si into pitch pyrolytic carbon shells and then in-situ removing the sodium chloride template can overcome the bottleneck. It is worth noting that our process for C@void/Si-G also offers a simple route for cost down and mass production of anode material. The C@void/Si-G anodes exhibit an excellent capacity of 1082.7 mAh g⁻¹ at 0.2 C after 200 cycles. Furthermore, it holds a high capacity retention of 81.9 % after 500 cycles at 0.5 C. We found that C@void/Si-G composite only rises about 41% volumetric expansion during 500 operation cycles. This can effectively avoid direct contact between silicon and electrolyte to form a stable solid electrolyte interphase (SEI) film. Especially, practical application of the C@void/Si-G anode is demonstrated in a full cell pairing with LiNi_0.3Co_0.3Mn_0.3O₂ cathode. The full cell presents great cycle retention of 90.1 % at 0.2 C after 100 cycles and a high energy density (446 Wh kg⁻¹).