Black P@MOx (M = Mg, Al, or Ti) composites as superior Li-ion battery anodes

Abstract

A simple, inexpensive, and scalable method for transforming phosphorous pentoxide (P2O5) into black phosphorus (BP)-based composites was developed. The BP-based composites of BP@MgO, BP@Al2O3, and BP@TiO2 synthesized by a one-pot mechanochemical reduction of P2O5 using Mg, Al, or Ti were composed of nanocrystalline BP within the metal oxide matrices of MgO, Al2O3, or TiO2, respectively. Subsequently, the potential of these composites as anode materials in rechargeable Li-ion batteries (LIBs) was investigated. BP@TiO2 showed the highest electrochemical performance among the BP-based composites. Specifically, the BP@TiO2 exhibited a high reversible capacity over 510 mAh g−1 after 300 cycles and a fast rate capability of ~ 400 mAh g−1 at the 3C rate. The superior electrochemical performance of BP@TiO2 was attributed to the well-dispersed nanocrystalline BP and the Li-reactive TiO2 matrix. Additionally, the formation of LixTiO2 in the Li-reactive TiO2 matrix during Li cycling increased the electrochemical Li-ion conductivity and diffusivity, contributing to the enhanced electrochemical performance. Therefore, the BP@TiO2 synthesized by the one-pot mechanochemical reduction has high potential as a superior LIB anode.