A Stable Core-Shell Si@SiO_x/C Anode Produced via the Spray and Pyrolysis Method for Lithium-Ion Batteries

In the critical situation of energy shortage and environmental problems, Si has been regarded as one of the most potential anode materials for next-generation lithium-ion batteries as a result of the relatively low delithiation potential and the eminent specific capacity. However, a Si anode is subjected to the huge volume expansion-contraction in the charging-discharging process, which can touch off pulverization of the bulk particles and worsens the cycle life. Herein, to reduce the volume change and improve the electrochemical performance, a novel Si@SiO_x/C anode with a core-shell structure is designed by spray and pyrolysis methods. The SiO_x/C shell not only ensures the structure stability and proves the high electrical conductivity but also prevents the penetration of electrolytes, so as to avoid the repetitive decomposition of electrolytes on the surface of Si particle. As expected, Si@SiO_x/C anode maintains the excellent discharge capacity of 1,333 mAh g^-1 after 100 cycles at a current density of 100 mA g^-1. Even if the current density reaches up to 2,000 mA g^-1, the capacity can still be maintained at 1,173 mAh g^-1. This work paves an effective way to develop Si-based anodes for high-energy density lithium-ion batteries.