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 tem-plate 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 LiNi0.3Co0.3Mn0.3O2 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).

Automated summary

Researchers have developed a novel carbon-coated porous structure for silicon anodes, which solves the instability issue caused by volume expansion. The material exhibits excellent cycling performance and capacity retention, making it suitable for practical application in lithium-ion batteries.