Interface regulation for stabilizing phosphorous electrode with cyclically formed hetero-interfaces enables durable lithium-ion storage

Abstract

Red phosphorus has attracted tremendous attention because of its high theoretical specific capacity, cost effective as well as environmental friendly characteristics. Nevertheless, its large volumetric expansion during the charge–discharge process and intrinsic poor conductivity have severely hindered the practical application of red phosphorus. A novel strategy of carbon-excluded in active materials to achieve performance improvement of red phosphorus is constructively explored by delicate interface regulations of building a dynamic hetero-interface on cycling. A very simple red phosphorus/sulfur (P/S) was prepared by moderately ball-milling process to achieve the purpose despite only two electron-insulating components of sulfur (S) and red phosphorus (P) are involved. The experiment results demonstrate that the in-situ formation of the temporary solid sheath of lithiated sulfur, which is partially incorporated in solid electrolyte interface (SEI) film around red phosphorus. It is the crucial factor to depress the decomposition of the electrolyte. Furthermore, theoretic calculations based on first-principles reveal that the built-in electric field in the transient interface of Li2S/P provides fast diffusion tunnels for ions and electrons, which facilitates to improve the kinetics of the electrode. Our research demonstrates the construction of dynamic hetero-interfaces have huge potentials to improve the sluggish kinetics of high capacity electrode materials.