Multifunctional Conductive and Elastic Matrices-Engineered Si Nanocomposite Anodes for Liquid and Solid-State Lithium...

Silicon anodes have intrinsically low electronic conductivity and severe volume changes, leading to nonuniform reaction kinetics and progressive structural degradation in both lithium-ion batteries (LIBs) and all-solid-state lithium batteries (ASSLBs). To overcome these limitations, we develop a silicon nanocomposite anode via a scalable and facile synthesis route. The nanocomposite (Si/a-Sn/CoSi₂/G/C) consists of ultrafine Si nanocrystallites integrated with a well-deformable, electronically conductive amorphous Sn; a mechanically robust and elastic CoSi₂ framework; a highly Li-reversible, electronically conductive, stress-mitigating graphite scaffold; and a highly elastic, electronically conductive PVC-pyrolyzed amorphous carbon shell. This hierarchical and synergistic architecture integrates uniform nanocrystalline Si dispersion, continuous electronic conduction, and mechanically rigid and elastically buffering matrices that accommodate volume expansion, thereby establishing a robust Si nanocomposite anode platform compatible with both LIBs and ASSLBs. The anode has a high reversible capacity, stable long-term cycling performance, high Coulombic efficiency, and improved rate capability. In LIB systems, a Si/a-Sn/CoSi₂/G/C|NCM811 full-cell achieves an energy density of 434.4 Wh kg^-1 with durable cycling stability. In sulfide-based ASSLB systems employing Li₆PS₅Cl, the full-cell has an energy density exceeding 300 Wh kg^-1, with structural and electrochemical stability. Thus, Si/a-Sn/CoSi₂/G/C is a practical and scalable Si-based anode platform for next-generation LIBs and ASSLBs.