Coral-like porous composite material of silicon and carbon synthesized by using diatomite as self-template and precursor with a good performance as anode of lithium-ions battery

Abstract

Developing silicon based anode of lithium-ion battery (LIB) is seriously blocked by the huge volume change of lithiation and delithiation and the corresponded high cost paying to solve it, although Si with the theoretical capacity of 4200 mAh g−1 for Li+ storage. In this study, natural diatomite with low cost was using as precursor and self-template to produce Si and construct porous structure, a coral-like porous Si/C (CLP-Si/C) material has been successfully synthesized through the NaCl added magnesiothermic reduction reaction (MRR) technology and acetylene CVD method. The hierarchical structure of macro-/mesopores in CLP-Si/C are inherited from diatomite itself and produced by removing the unreacted SiO2 in diatomite and the byproduct of MgO of MRR. Acetylene CVD further constructs a shell-core structure of carbon layers and Si particles. The hierarchical pores and core-shell structure make CLP-Si/C exhibit a stable cycling performance as LIB anode that the capacity of 990.6 mAh g−1 can be kept after 100 cycles at a rate of 250 mA g−1. This work provides a simple, low-cost and scalable strategy for producing porous Si/C anode materials with high-performance by using diatomite as both precursor and template, and is promising in the development of practical application of Si based anode materials of lithium-ion battery.