Controlled Interfacial Tailoring of Hierarchical Silicon Synergizes Charge Transport Enabling Stable and Fast Lithium Storage

Silicon is a promising anode material candidate but encounters volume change and capacity decay issues. Although diverse demonstrations in structural and interfacial engineering, the performance toward industrial applications remains to be improved. Herein, a controlled interfacial tailoring strategy is proposed for micro-nano hierarchically structured silicon. The resultant granules, consisting of randomly interconnected silicon debris modified by an electrically conductive carbon layer and a superionic sulfide conductor specifically in a controlled form (nanoparticles, coats, and matrices), attain distinctly different cyclic performances. As the carbon coating generally provides electron transfer paths for silicon, the introduced fast ion conductor exhibits a strong correlation with its configuration in facilitating ion transportation as well as improving the materials utilization and cyclic stability. Impressively, the granules encapsulated with a fast ion conductor layer show remarkably improved cycling performance and rate capability, attributable to a decent synergy of transmitting both electrons and lithium ions throughout the granule.