Metallic two-dimensional P2C3: A promising flexible anode for high-performance potassium-ion batteries

Due to the earth-abundant potassium resource and intrinsic safety, potassium ion batteries (KIBs) are widely regarded as a promising alternative to lithium ion batteries. Nonetheless, the development of KIBs is very slow and severely impeded by the lack of a suitable anode material. Herein, based on the comprehensive first principles computations, we systematically explored the recently developed phosphorus carbide (P2C3) monolayer as an anode of KIBs. Our results demonstrate that P2C3 exhibits a metallic characteristic, providing good electrical conductivity for the rapid electronic transport. Meanwhile, P2C3 monolayer possesses excellent mechanical flexibility and large adsorption energy (-3.25 to -2.41 eV), which could avoid the anode pulverization during cycling. Furthermore, the theoretical capacity of P2C3 is 729.28 mA h/g, higher than most of the reported KIBs anode materials. The lowest diffusion barrier of K ion is only 0.0053 eV. All these appealing results demonstrate that P2C3 monolayer is an outstanding flexible anode of KIBs.