Two-dimensional SiP3 monolayer as promising anode with Record-high capacity and fast diffusion for Alkali-ion battery

Abstract

Development of high-performance two-dimensional anode materials is the key to rechargeable battery applications. Based on the first principles, the structure and electronic properties of SiP3 monolayer, blue phosphorus and silicene are researched systematically. SiP3 monolayer has high cohesive energy, excellent molecular dynamics, mechanical and thermal stability. The metal properties of SiP3 monolayer ensure that the battery maintains excellent electrical conductivity. Remarkably, the specific capacities of Li, Na and K-ion battery are as high as 2658.4, 1993.8 and 1107.8 mAh/g, respectively, far higher than those of pristine BlueP, while the changes of lattice parameters are only 8.32, 3.21 and 4.81 %, respectively. In addition, the existence of phosphorus atom six membered ring accelerates the diffusion of Li, Na and K-ions, and their diffusion barriers are 0.11, 0.06 and 0.03 eV, respectively. The low diffusion barrier and average open circuit voltage of SiP3 monolayer ensure fast charge and discharge and long service life in practical applications. These findings indicate that SiP3 monolayer is suitable to be used as high-performance anode material for Li, Na and K-ion batteries.