BeN4 monolayer as an excellent Dirac anode material for potassium-ion batteries

Rapid development of anode materials with good stability, high capacity, low diffusion barrier and excellent cyclability is an important challenge for the further enhancement of the battery industry today. Recently, a novel stable two-dimensional (2-D) material named beryllonitrene (BeN4) has been experimentally synthesized. Considering its lightweight and porous structure, we systematically investigate the feasibility of BeN4 monolayer as an anode material for metal ion batteries (MIBs) based on first-principles calculations. We investigate the adsorption behavior of Li/Na/K on BeN4 monolayer surfaces, and find that BeN4 monolayer with Dirac cone can only stably adsorb potassium and possess good electrical conductivity before and after adsorption of potassium. More noteworthy is that BeN4 monolayer has fairly low diffusion barrier (62 meV) and open circuit voltage (0.084–0.179 V), as well as very high storage capacity (842 mA h g−1), which are superior to most 2-D anode materials for potassium-ion batteries (PIBs). Moreover, BeN4 monolayer is also demonstrated to have great cycle stability and long-term cycle life. Therefore, our results suggest that BeN4 monolayer is expected to become a pretty perfect Dirac anode material for PIBs.