Preparation and lithium-storage performance of attapulgite-derived Si@C composite

Silicon is considered as one of the most promising anode materials of next generation lithium-ion battery (LIBs) due to its extremely high theoretic capacity. However, its applications in LIBs are hindered by the high-cost and harsh synthesis conditions of silicon nanomaterials. In this paper, the natural attapulgite was selected as the precursor for the synthesis of silicon nanoparticles (MRR Si) via hydrothermal purification process followed by magnesium reduction process. By adopting chemical vapor deposition, MRR Si@C composite was prepared and its electrochemical performance was evaluated. Results indicate that the synthesized MRR Si can deliver a high discharge capacity of 2 362 mAh/g under a current density of 0.2 A/g with a coulombic efficiency (CE) of 71.87%. After 100 cycles at 0.5 A/g, the MRR Si-based electrode can deliver a capacity of 909 mAh/g. After the deposition of carbon film, the resulted MRR Si@C composite can deliver a high capacity of 2 494 mAh/g with an enhanced CE of 78.92% and a high capacity of 1 324 mAh/g after 100 cycles at 0.5 A/g. More importantly, the MRR Si@C composite can still remain a high capacity of 844 mAh/g at a high current density of 5 A/g, implying a good rate capability and promising applications of MRR Si in LIBs.