Industrial waste silicon-based FeSi2/N, S, O-doped mesoporous carbon anode with high capacity and long-term stability for lithium-ion batteries

As a remarkable alternative anode to commercial graphite for the next-generation high-performance lithium-ion batteries (LIBs), silicon (Si) has attracted tremendous attention due to its high specific capacity. However, the enormous volume expansions/contractions during the charge/discharge limited its practical application in LIBs greatly. To solve these issues, herein, we fabricated a low-cost FeSi intermetallic compound (FeSi 2 ) by the ball milling with photovoltaic industrial waste micron-sized Si and Fe powders as raw materials and encapsulated it by N, S, O-doped mesoporous carbon with polyvinylpyrrolidone as C, N, O precursor and (NH 4 ) 2 SO 4 as template and pore-introducing agent. Owing to the presence of FeSi 2 , abundant meso-pores for mitigating Si and FeSi 2 expansion and the N, S, O-doped mesoporous carbon for facilitating lithium-ion transport and electron conduction, one as-prepared FeSi 2 /N, S, O-doped mesoporous carbon composite anode (FeSiA 1 @C) showed a high specific capacity of 401.7 mAh g −1 even at 1.0 A g −1 after 1600 cycles. More impressively, the assembled LiFePO 4 || 20 % FeSiA 1 @C/80 % commercial graphite full cell presented a high energy density of ca. 312.0 Wh kg −1 and a capacity retention of ca. 80 % after 500 cycles, demonstrating a promising practical applicability of FeSiA 1 @C anode, and showing a new way for the high-value utilization of industrial waste micron-sized Si for LIBs.