Mild Chemical Lithiation Strategy for Achieving Synergistic Lithium-Compensation and Carbon-Coating on SiO Anodes

Silicon monoxide (SiO x , x ≈ 1) has emerged as a promising anode material for next-generation lithium-ion batteries (LIBs) due to its high theoretical capacity. However, its commercial viability is hindered by low initial Coulombic efficiency (ICE) and insufficient cycling stability. Herein, a mild chemical lithiation strategy is proposed that synergistically integrates lithium-compensation and carbon-coating to address these challenges, significantly boosting the electrochemical performance of SiO anode. Biphenyl-lithium/2-methyltetrahydrofuran (Bp-Li/2-MeTHF) is elaborately selected as a dual-functional chemical lithiation reagent to ensure sufficient lithium incorporation into SiO at room temperature and simultaneously biphenyl (Bp *− ) radical in-situ polymerizes, then is converted into a carbon shell on a silicon/lithium silicates core upon subsequent thermal annealing (Li-SiO@C). This unique structure of Li-SiO@C effectively compensates for irreversible lithium loss and buffers volume expansion, leading to an exceptional ICE of 91.0% and remarkable capacity retention of 92.2% after 500 cycles, far surpassing the 72.9% ICE and 9.0% retention observed in the pristine SiO anode. Moreover, Li-SiO@C demonstrates excellent moisture resistance that is well suited for aqueous-based electrode coating processes. This work presents a simple yet effective strategy to enhance the electrochemical performance of SiO anodes, offering strong potential for large-scale applications in high-energy-density LIBs.