A submicron Si@C core-shell intertwined with carbon nanowires and graphene nanosheet as a high-performance anode material for lithium ion battery

Silicon is widely used as anode for lithium-ion batteries (LIBs). However, its application is limited due to some problems such as large volume expansion. In this work, silicon waste from wafer slicing via diamond wire saw technology in photovoltaic industry is used as raw materials. A submicron core-shell structure Si@C intertwined with CNWs and graphene nanosheet, is prepared as anode for LIBs by hydrothermal process. The anode retains a specific capacity of 2514.8 mAh g(-1) with capacity retention of 75.8% after 360 cycles under a current of 0.1 C and 1548.9 mAh g(-1) after 1000 cycles under 0.2 C. In addition, it maintains 1596.9 mAh g(-1) (1.0 C), 925.3 mAh g(-1) (2.0 C) after several rate testing of 0.1 C to 2.0 C. A COMSOL Multiphysics and MD simulation are performed to examine the lithiation-induced volume expansion of silicon. The results demonstrate that, the lamellar micron silicon can achieve a stable lithium intercalating capacity larger than 2100 mAh g(-1), which agrees well with our experimental results. It is demonstrated that the submicron Si from the kerf waste in the photovoltaic slicing process via diamond wire saw technology are available as direct raw materials for high performance anode of LIBs.