Theoretical prediction of stable WB4 monolayer as a high-capacity anode material for alkali-metal ion batteries

As a rapidly evolving 2D monolayer material, tungsten tetraboride MBene exhibits innate advantages in electrochemical applications because of its unique graphene-like structure and metallic properties. In this study, we utilized first-principles calculations to identify the potential applications of WB4 as an anode material in rechargeable alkali-metal-ion batteries. The findings imply that the Li, Na, and K adsorption on the WB4 surface results in exceptionally high conductivity, and the WB4 monolayer can effectively adsorb these ions with significant adsorption energies of -2.516 eV, -2.356 eV, and -2.941 eV for Li, Na, and K ions, respectively. The results indicate that WB4 exhibits excellent stability during lithiation, sodiation, and potassiation. Notably, we propose high storage capacities for LIBs (708mAh/g), SIBs (472mAh/g), and KIBs (177 mAh/g), with maintained structural stability for the adsorption of these metal ions. The measured average open circuit voltages for WB4 were found to be 0.77 V (Li), 0.73 V (Na), and 0.80 V (K), and metallicity remain good maintained within the entire adsorption process. The calculated migration energy barriers for Li, Na, and K were 0.47 eV,0.21 eV and 0.13 eV respectively. The notable properties of WB4 make it an advantageous electrode material for alkali-metal ion batteries.