Fabrication of Carbon/Silicon Composite as Lithium-ion Anode with Enhanced Cycling Stability

In this work, a micro-carbon/nano-silicon hybrid material is synthesized via a scalable and practical solid-state process for rechargeable Li-ion battery anodes. The carbon encapsulated silicon composite is produced by a two-step thermal reduction of commercial wheat flour. This silicon-carbon hybrid demonstrates a stable gravimetric capacity of ca. 1500 mAh g−1 Si (equivalently, 700 mAh g−1 composite mass) from galvanostatic cycling for 90 cycles at a cycling rate of C/20. Multi-rate cycling shows the silicon-carbon hybrid performs with stable gravimetric capacities of 830 mAh g−1 at C/10 and 300 mAh g−1 at 1C. After prolonged cycling, the carbon-silicon hybrid further demonstrates superior mechanical and electrochemical resilience when compared to unencapsulated silicon electrode: greater composite conductivity (ca. 4 times larger at full lithiation), lower electrode deformation, and less SEI formation.