Fast-Charging Analytics of Silicon-Graphite Composite Electrodes for Lithium-Ion Batteries

Fast charging of lithium-ion batteries is often hindered by lithium plating and structural degradation in conventional graphite and silicon anodes. To address these challenges, this study investigates a composite anode comprising 80 wt % graphite and 20 wt % silicon, focusing on rate-dependent electrochemical performance under fast-charging conditions using a three-electrode configuration. Open-circuit voltage (OCV) and impedance analyses across varying state-of-charge (SOC) and temperatures reveal that composite anodes deliver improved electrochemical performance associated with multiple lithiation phases, compared to pure graphite or silicon anodes. The superior rate capability and extended cycle life are attributed to mitigated volume expansion, reduced mechanical degradation, and suppressed lithium plating at the composite anode. A comprehensive mechanistic understanding of cell operation techniques and their role in mitigating degradation pathways is also presented, underscoring the promise of composite anodes for reliable fast-charging applications.