Self-Limiting Partial Lithiation Induced by Interfacial Heavy Doping Boosts Li-Storage Performance in Holey Silicon Nanosheets.

Partial lithiation has emerged as a promising strategy to mitigate the volume expansion in silicon anodes. However, current implementations predominantly rely on externally imposed constraint approaches and inevitably sacrifice substantial capacity. Herein, an innovative self-limiting partial lithiation strategy driven by interfacial heavy doping is proposed. Through ice-templated self-assembly of sol particles, the localized high-concentration P-doping is achieved at interconnected particle interfaces in 2D holey Si nanosheets. This interfacial heavy doping triggers a "region-selective lithium shielding" effect, enabling in situ passivation and sustained retention of trace crystalline silicon domains during cycling. These retained crystalline domains, with dual characteristics of electrochemical inertness and self-buffering mechanism, effectively mitigate the volume expansion of silicon anodes while causing only minimal capacity loss. Thanks to the partial lithiation behavior in holey self-assembled nanosheets, the P-doped silicon anode demonstrates remarkable cycling stability (2176.2 mAh g after 200 cycles at 0.5 A g). Although P-doping locally impedes Li transport in heavily doped regions, it significantly promotes lithium-ion kinetics in P-poor/P-free domains. Coupled with the improved electron conductivity, this synergy effect leads to superior rate capability (1590 mAh g at 2 A g).