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

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 °C (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 mAh/g at a current density of 100 mA/g. At 1000 mA/g, this anode retains a reversible capacity of 1673 mAh/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