Surface-Coating Strategies of Si-Negative Electrode Materials in Lithium-Ion Batteries

Silicon (Si) is recognized as a promising candidate for next-generation lithium-ion batteries (LIBs) owing to its high theoretical specific capacity (~4200 mAh g−1), low working potential (<0.4 V vs. Li/Li+), and abundant reserves. However, several challenges, such as severe volumetric changes (>300%) during lithiation/delithiation, unstable solid–electrolyte interphase (SEI) formation, and inherently low electrical and ionic conductivity, impede its practical application. To mitigate these challenges, direct contact between the surface of the Si particle and the electrolyte must be prevented. In this review, we elucidated the surface coating strategies to enhance the electro–chemical performance of Si-based materials. We identified the impact of various coating methods and materials on the performance of Si electrodes. Furthermore, the integration of coating strategies with nanostructure design can effectively buffer Si electrode volume expansion and prevent direct contact with the electrolyte, thereby synergistically enhancing electrochemical performance. We highlight opportunities and perspectives for future research on Si-negative electrodes in LIBs, drawing on insights from previous studies.