Multi-scale spatial Design of Dual‑carbon Encapsulated Silicon Anode towards efficient Lithium storage

Silicon (Si) has emerged as an attractive anode candidate for high-performance lithium-ion batteries, thanks to its distinctive alloying reaction mechanism and exceptionally high theoretical capacity. Nevertheless, its intrinsically low electronic conductivity, combined with severe volume expansion and shrinkage during lithiation/delithiation, typically leads to rapid capacity decay and particle pulverization. To address these challenges, this study proposes a multi-scale spatial design strategy for Si anode with dual‑carbon encapsulation, fabricated through a core-shell design based on zeolite imidazolate framework-8 (ZIF-8) core and polymerized dopamine (PDA) shell. During the subsequent annealing process, the embedded Si nanoparticles are coated with a nitrogen-doped carbon layer derived from ZIF-8, while the interfacial interaction of ZIF-8 with PDA promotes the formation of a hollow interior. Consequently, the tightly wrapped carbon layer, together with the hollow architecture, not only enhances electronic conductivity but also provides an effective buffering matrix. As a result, the composite anode exhibits improved charge-transfer kinetics and enhanced electrode integrity, which collectively contribute to its modified lithium storage performance. Specifically, the optimized anode delivers a specific capacity of 1099.5 mAh g^-1 after 350 cycles, along with excellent rate capability (685.6 mAh g^-1 at 5.0 A g^-1). Importantly, the dual‑carbon encapsulation strategy demonstrated here offers a feasible and generalizable approach to simultaneously improve electronic conduction and structural stability, extending its potential applicability to other electrode materials beyond Si anodes.