First-principles outlook of two-dimensional B3O3 monolayer as an anode material for non-lithium ion (K+, Ca2+, and Al3+) batteries

The rapid development of high-capacity anodes for non-lithium ion batteries (NLIBs) has attracted significant attention in the scientific community towards removing fossil fuels. Herein, first-principles calculations based on density functional theory (DFT) were utilized to look into the applicability of the hexagonal boron oxide (B3O3) monolayer as an anode material for non-lithium ion (K+, Ca2+, and Al3+) batteries. The K+, Ca2+, and Al3+ ions are preferentially adsorbed on the large hollow site of B3O3 monolayer with binding energies of −53.77, −170.55, and −620.85 kcal mol−1, respectively. It was found the adsorption energies generally decrease by increasing the metal ion concentration. The theoretical storage capacities were predicted to be 790.33, 1185.50, and 1778.25 mAh g−1 for K+, Ca2+, and Al3+ ions, respectively. Furthermore, the diffusion energy barrier of a single metal ion was very low (0.22/0.39, 0.12/0.35, and 0.17/0.05 eV for K+, Ca2+, and Al3+ ions, respectively). The findings suggested that the B3O3 monolayer can be used in designing high-performance boron-containing nanostructures for NLIBs.