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).