Abstract

Silicon is a promising anode material for lithium-ion batteries (LIBs) due to its high theoretical capacity. However, its practical application is hindered by severe volume expansion and low electrical conductivity. To improve stability, silicon/graphite (Si/G) composites are commonly used, but achieving uniform integration remains challenging due to the distinct surface chemistry of silicon and graphite. To address this issue, we developed a surface modification strategy integrating silicon oxidation treatment and polyvinylpyrrolidone (PVP) as an amphiphilic stabilizer to enhance dispersion, interfacial bonding, and structural stability in Si/G composites. The oxidation treatment introduced hydroxyl functional groups on the silicon surface, improving its hydrophilicity and facilitating strong interactions with PVP. Simultaneously, PVP acted as a chemical bridge, stabilizing graphite while reinforcing adhesion between silicon and graphite. The subsequent carbonization of PVP generated N-doped carbon, improving electrical conductivity and mechanical integrity. The resulting composite exhibited an initial specific capacity of 717 mAh g−1 and retained 92.3 % of its capacity after 500 cycles. Furthermore, the modified composite demonstrated reduced electrode thickness after cycling, effectively mitigating volume expansion. This study exhibits the effectiveness of tailored interfacial chemistry and structural engineering in developing long-lifespan Si/G composites for next-generation LIBs. The proposed approach offers a scalable, environmentally friendly solution for industrial implementation, paving the way for energy storage technologies with enhanced cycle stability and electrochemical performance.

DOI: 10.1016/j.jallcom.2025.181670

LINK: https://doi.org/10.1016/j.jallcom.2025.181670