Single-Step Flash-Heat-Treatment Synthesized Flame-Retardant Red Phosphorus/Graphene Composite as Flexible Anode for Sodium-Ion Batteries*

Among all of the anode materials for Na-ion batteries, phosphorus guarantees its role with the high theoretical specific capacity of ~ 2600 mAh/g, and the red phosphorus (RP) is the most cost-effective allotrope. In this work, a facile single-step flash-heat-treatment synthesis method was developed to realize the reduction of graphene oxide (GO) and deposition of RP onto the reduced graphene oxide (rGO) sheets simultaneously, and the resulted RP/rGO composite has been subsequently demonstrated to solve the poor electronic conductivity and large volume variation issues of RP during cycling. The RP/rGO flexible film anode achieved an average capacity of 1625 mAh/g during the 200 cycles at 1 A/g charge/discharge current density. Average charge capacities of 1786, 1597, 1324 and 679 mAh/g at 1, 2, 4, and 6 A/g current densities were obtained in the rate capability test, respectively. Moreover, the RP/rGO film also presented excellent flame retardancy over the rGO film by taking the advantage of the RP ingredient.