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

• SiP 3 monolayer is designed as anode materials for rechargeable metal-ion batteries. • The properties of SiP 3 monolayer as anode is fully explored by DFT calculations. • Li/Na-SiP 3 monolayer can offer theoretical capacity of 2658.4 mA h/g and 1993.8 mA h/g. • Ultra-low diffusion barrier 0.11, 0.06 and 0.03 eV for Li, Na and K-ion batteries. 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 SiP 3 monolayer, blue phosphorus and silicene are researched systematically. SiP 3 monolayer has high cohesive energy, excellent molecular dynamics, mechanical and thermal stability. The metal properties of SiP 3 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 SiP 3 monolayer ensure fast charge and discharge and long service life in practical applications. These findings indicate that SiP 3 monolayer is suitable to be used as high-performance anode material for Li, Na and K-ion batteries.