High stability of sub-micro-sized silicon/carbon composites using recycling Silicon waste for lithium-ion battery anode

Silicon-carbon composite is recognized as one of the most promising anodes for high-energy lithium-ion batteries. In this work, a kind of sub-micro-sized silicon (Si) recycled from solar cell industrial cutting waste has been explored as lithium-ion battery anode through a simple compound process. Coated and bound by chitosan pyrolyzed hard carbon, the Si particles (most) were distributed in graphite particles in a balanced way to form silicon-graphite-carbon (SCG) composite. Hence, as-prepared SCG anode delivers a stable cycling performance, with a reversable capacity of 741 mAh g⁻¹ at 100 mA g⁻¹ after 400 cycles and retention of 98.8%. In addition, that the slower electrolyte penetration phenomenon for chitosan derived hard carbon anode plus SCG anode has been found, should and can be modified by pre-activation. The better stability as well as higher rate capability (587 mAh g⁻¹ at 400 mA g⁻¹) of SCG anode proved that the strategy of hard carbon as a glue while graphite as main frame structure works on making up defects of sub-micron Si. The remarkable cycling performances and low-cost manufacturing process make Si particles of larger size also show important commercial application values.