Matryoshka-type carbon-stabilized hollow Si spheres as an advanced anode material for lithium-ion batteries

摘要

Silicon(Si)is regarded as the potential anode for lithium-ion batteries(LIBs),due to the remarkable theoretical specific capacity and low voltage plateau.However,the rapid capacity decay resulting from volume variation and slow electron/ion transportation of Si limit its practical application.Here,matryoshka-type carbon-stabilized hollow silicon spheres(Si/C/Si/C)are synthesized by an aluminothermic reduction and calcination process.The Si/C/Si/C anode materials prepared at 500℃(Si/C/Si/C-500)exhibit unique structures,in which amorphous region and porous structure are preserved in the Si layers.The anode based on Si/C/Si/C-500 displays an initial specific capacity of 2792 m Ah/g at a current density of 100 m A/g.At 1000 m A/g,this anode retains a reversible capacity of 1673 m Ah/g,86.9%of the initial capacity after 200 cycles.Such synthetic strategy can be employed to fabricate other high-capacity anode materials with large volume variation during charge/discharge process.