A Mixed-Conducting Strategy Enabling Uniform Prelithiation of Silicon-Based Lithium-Ion Batteries

Abstract

Prelithiation has been widely recognized as an effective strategy to mitigate the low initial Coulombic Efficiency of silicon-carbon (Si-C) anodes in lithium-ion batteries. Conventional prelithiation methods suffer from non-uniform lithium distribution and unstable formation of solid electrolyte interphase (SEI). To address these issues, this work introduced a mixed electron-ion conductor (MEIC) as a multifunctional additive to establish dual conductive pathways enabling concurrent electron and ion transport. This strategy enhances lithium-ion diffusion kinetics and charge transfer efficiency through a hybrid electron-ion conductive network. Physical characterizations reveal that the mixed-conducting strategy enables uniform prelithiation and promotes the formation of a stronger SEI. Electrochemical testing of full cells demonstrates that MEIC modified electrodes achieve an initial Coulombic Efficiency of 94.5% and a capacity retention of 66.1% after 500 cycles at 1 C, outperforming traditional contact prelithiation methods by 22%. Even at a high rate of 2.0 C, the capacity of MEIC-based electrodes is improved compared to conventional counterparts. Notably, this strategy is fully compatible with roll-to-roll manufacturing processes, offering a scalable pathway for high-energy-density Si-C anodes in practical applications.