In situ synthesis of stable silicon carbide-reinforced silicon nanosheets from organoclay for high-performance lithium-ion battery anodes

Abstract

The extreme volume change of silicon anode causes fast capacity decay and short cycle life of lithium-ion batteries (LIBs). Thus, the development of stable Si-based anodes to avoid fractures of electrode materials is critical to their commercial applications. Herein, we designed a mechanically stable silicon carbide-reinforced silicon (Si/SiC) material via a facile molten salt-assisted magnesiothermic reduction of the carbonized organoclay. The as-prepared Si/SiC sample inherited the intrinsic layered structure of clay minerals. Benefiting from the atomic-scale direct contact of silicon oxide and carbon in organoclay precursor, β-SiC nanoparticles grew in situ in the Si nanosheets to form a heterostructure with strong bonding, thanks to their similar cubic crystal structure. The Si/SiC anodes exhibited enhanced cycling performance as anodes in LIBs, as compared with pure nanosilicon, which was attributed to the incorporation of SiC nanoparticles, the robust interface structure, and the hierarchical pore structure. Specifically, the Si/SiC nanocomposites containing 11 wt% SiC exhibited a high gravimetric capacity of 1507 mAh g−1, with 72% capacity being retained after 100 cycles at 1 A g−1. Coupled with the LiCoO2 cathode, the full cell showed a high capacity of 148 mAh g−1 after 100 cycles at 0.5C, demonstrating its potential for application in LIBs.