A low-cost silicon-graphite anode made from recycled graphite of spent lithium-ion batteries

Recycling graphite from spent lithium-ion batteries has substantial significance in protection of environment as well as in growth of economic. Silicon-graphite composite materials have been extensively studied and expected to replace graphite in commercial lithium-ion batteries, but it is still difficult to reduce the volume expansion of silicon. In this paper, we find that spent graphite is an ideal choice for low cost production of high-performance silicon-graphite composite, because the treated spent graphite (T-SGT) presents a porous structure which can be well combined with silicon and effectively relieve the volume expansion. The carbon coated silicon-treated spent graphite (T-SGT/Si@C) anode exhibits good cycling performance (92.47% capacity retention) over 300 cycles and good rate property (434.1 mAh g(-1) at a current density of 500 mA g(-1)), much better than carbon coated silicon-commercial graphite (CGT/Si@C).