Tailoring Hollow Silicon-Carbon Nanocomposites As High-Performance Anodes in Secondary Lithium-Based Batteries through Economical Chemistry

A sustainable synthesis procedure of a rational-designed silicon-carbon electrode for a high-performance rechargeable Li-based battery has been developed. It was realized by an economical approach using low-cost trichlorosilane as feedstock and without special equipment. The synthesis strategy includes polycondensation of trichlorosilane in the presence of a surfactant to selectively form spheric silicon@silica particles via a hydrogen silsesquioxane (HSQ) intermediate. After subsequent carbonization of a sucrose shell and etching the composite, we obtained an anode material based on silicon nanoparticles with 2-5-nm average diameter inside a porous carbon scaffold. The active material exhibits a high rate capability of 2000 mAh/g at a current rate of 0.5 A/g with exceptional cycle stability. After almost 1000 times of deep discharge galvanostatic cycling at 2.5 A/g current rate the capacity is still 60% of the initial 1200 mAh/g. The excellent electrochemical performance is attributed to an interaction of a stabilized solid electrolyte interface on extreme small silicon particles and a well-designed porous carbon cage which serves as efficient charge conductor.