A Covalent P–C Bond Stabilizes Red Phosphorus in an Engineered Carbon Host for High-Performance Lithium-Ion Battery Anodes

Abstract

The red phosphorus (RP) anode has attracted great attention due to its high theoretical specific capacity (2596 mAh/g) and suitable lithiation potential. To solve the inherent poor electrical conductivity and the large volume expansion due to the lithiation process, a vaporization-condensation strategy is considered as a promising method. However, there are two important issues that deserve attention in the vaporization-condensation process. First, the low P mass loading in the carbon-based frameworks (∼30 wt %) limits the energy density. Second, a residual white phosphorus (WP) leads to the safety problems of flammability and high toxicity. Herein, we found that the edge structure of carbon framework can offer the strong adsorption for P₄ and form a P-C bond, which accelerate the adsorption and polymerization of P₄ leading to high P mass loading and safety. When the porous carbon (PC) with plenty of edge carbons was used as the matrix to load P by vaporization-condensation, the RP loading is close to the highest theoretical mass loading of ∼50 wt % calculated based on the feeding ratio of RP/PC = 1/1. Therefore, the RP-PC anode provides a high specific capacity of 965.2 mAh/g even after 1100 cycles at 1000 mA/g (equivalent to 1 C) and a high-rate capacity of 496.8 mAh/g at 8320 mA/g (equivalent to 16.7 C) after 1000 cycles (the specific capacity and current density are calculated based on the total weight of RP and PC).