Silicon Anode Modification Strategies in Solid-State Lithium-Ion Batteries

The development and application of solid-state electrolytes in lithium-ion batteries (LIBs) have become mainstream in the industry of LIBs. Compared with liquid electrolytes, solid-state electrolytes offer higher safety and energy density and are expected to further broaden the application fields of lithium-ion batteries. Conventional solid-state lithium-ion batteries (SSLIBs) employ lithium metal as their anode, which raises new concerns about their safety and waste management. Therefore, silicon, with high safety, high theoretical capacity, low electrochemical plateau, and low handle cost, has become the most promising new-generation anode material. However, due to the volume expansion of silicon and the low contact with solid-state electrolytes, resulting in poor conductivity, the SSLIBs' capacity has not reached the expected level and the cycle performance is also poor. Therefore, further modification of silicon anodes has become one of the key points in the development of SSLIBs. This paper comprehensively expounds on the application and optimization of silicon anodes in SSLIBs. It proposes further optimization strategies, which focus on preventing the destruction of silicon and extending its lifespan. The strategies include (1) silicon with different morphologies; (2) the formation of amorphous silicon; and (3) silicon composites.