Tri-isolation and tri-conductive Si/CuCo-NC@rGO hierarchical architecture enabling highly stable and fast-kinetic silicon anodes for lithium-ion batteries

Silicon holds exceptional promise as a next-generation lithium-ion battery anode, yet its practical deployment remains hindered by drastic volume fluctuations, unstable interphases, and intrinsically poor electronic conductivity. This work reports a triple-isolation and triple-conductive hierarchical architecture (Si/CuCo-NC@rGO), which enables independent regulation and synergistic optimization of mechanical stability and electron transport. In this system, silicon nanoparticles are encapsulated within a MOF-derived N-doped porous carbon framework and are further constrained by an externally distributed network of metallic nanoparticles and reduced graphene oxide (rGO). This hierarchical configuration simultaneously ensures mechanical stability and enables efficient charge transport. The introduction of graphene effectively suppresses the aggregation of MOF-derived metal species during pyrolysis, leading to the in-situ formation of ultrasmall and uniformly dispersed Cu/Co nanoparticles (∼20 nm) embedded in a highly defective N-doped carbon matrix. This multilevel architecture provides robust mechanical buffering, abundant ion-accessible channels, and a multiscale electron-transport network, while the flexible rGO shell maintains long-range electrical continuity and interfacial integrity during repeated cycling. Such cooperative confinement markedly accelerates Li + diffusion, enhances pseudocapacitive contributions, facilitates uniform SEI formation, and significantly suppresses Si expansion from 151.7% to only 48.6% after cycling. Benefiting from these synergistic effects, the optimized composite delivers a reversible capacity of 1013.2 mAh g −1 over 700 cycles at 1 A g −1 and an exceptional rate capability of 1160.6 mAh g −1 at 5 A g −1 . This work presents a generalizable structural engineering strategy that enables the independent regulation and synergistic optimization of mechanical stability and electronic transport, offering valuable design insights for the development of long-life, high-performance silicon anodes for advanced lithium-ion batteries.