High capacity SiAl/C anode material for lithium-ion batteries

High capacity anode material SiAl/C composite was prepared by thermal annealing process. Its structure was characterized by XRD and its cyclability and potentiostatic cycling performance were investigated. The charging and discharging test shows SiAl/C composite possesses higher capacity than carbonaceous mesophase spherules. And its first irreversible capacity is decreased, comparing with Si/C composite prepared under the same conditions. It is demonstrated that by adding Al into Si/C composite system, its first Li+ insertion depth is suppressed and voltage hysteresis is alleviated. Obtained SiAl/C composite anode material has a capacity about 600 mAh/g for its first Li⁺ insertion and its coulombic efficiency for the first cycle is up to 85%. And after 25 cycles, its capacity retention can be retained about 90%.