From Alloy to Anode: Pitch-Assisted Synthesis of High-Performance SiOx/Gr@C from Fe-C-Si Alloy Precursors

SiOx has surfaced as a notably promising high-capacity anode material for next-generation LIBs owing to its remarkable theoretical capacity and cost benefits. Nonetheless, its practical application is hindered by severe volume expansion, material pulverization, electrode detachment, and intrinsically low electronic conductivity. To tackle these challenges, we developed an innovative strategy involving "acid etching-mechanical activation-high-temperature carbonization" to synthesize asphalt-coated lamellar SiOx/Gr@C-X composites from Fe-C-Si alloy precursors. Among the prepared materials, the SiOx/Gr@C-15 composite achieved optimal electrochemical performance: it retained a reversible capacity of 672.85 mAh g^-1 after 100 cycles at 0.2 A g^-1 and maintained a capacity of 323.62 mAh g^-1 at 1 A g^-1. Measurements using the GITT and EIS confirmed that SiOx/Gr@C-15 exhibited the highest Li⁺ diffusion coefficient (D_Li⁺) and the lowest SEI resistance in the series. This work not only realizes the high-value utilization of Fe-C-Si alloys but also provides a rationale for material design in the development of high-energy-density LIBs.