Metallic 1H-BeP2 monolayer as a potential anode material for Li-ion/Na-ion batteries: A first principles study

The selection of a suitable two-dimensional anode material is a fundamental step in developing the batteries to gain excellent performance. Herein, based on the comprehensive first-principles computations, we systematically explored the possibility of two-dimensional 1 H-BeP2 monolayer as the anode material of lithium/sodium-ion (Li/Na-ion) batteries. Our results show that 1 H-BeP2 monolayer possesses metal characteristics, which pro-vides good conductivity and can effectively guarantee fast electronic transmission. Meanwhile, the 1 H-BeP2 monolayer possesses thermal and dynamic stabilities. In addition, it is worth noting that 1 H-BeP2 monolayer also has other excellent performance required for metal-ion batteries anode, not only a high theoretical storage ca-pacity of 755 mAh/g, but also an ultra-low diffusion barrier (Li/Na: 0.198/0.095 eV) and low average open-circuit voltage (Li/Na: 0.69/0.36 eV). Furthermore, it also possesses a relatively small lattice changes (Li/Na: 4.8/3.4%) during the charge and discharge process. Finally, the metallic behavior of the 1 H-BeP2 monolayer is maintained throughout with different adsorption concentrations of Li/Na ions, which is an excellent feature for the battery application. All these appealing results demonstrate that 1 H-BeP2 monolayer is a promising flexible anode of Li/Na-ion batteries.