A DFT-based design of B/N/P-co-doped oxo-triarylmethyl as a robust anode material for magnesium-ion batteries

Abstract

Magnesium-ion batteries (MIBs) are emerging as a promising alternative to lithium-ion batteries (LIBs) due to their superior safety features and cost-effectiveness. In this work, heteroatoms-co-doped oxo-triarylmethyl (B/N/P@oxTAM) as a favorable anode material for MIBs was investigated using density functional theory calculations. The B/N/P@oxTAM is a highly porous structure and has a better affinity for Mg-ions to attach to vacancy site. Partial density of states, open-circuit voltage, theoretical specific capacity, and diffusion energy barrier were calculated and discussed. A significant decrease in the HOMO-LUMO gap with no structural deformation occurred, suggesting the high cycling performance of B/N/P@oxTAM for MIBs. Moreover, the designed anode material demonstrated full loading with six Mg-ions at different active sites, indicating a high theoretical specific capacity of 513.75 mAh g−1 and a low open-circuit voltage of 0.07 V. The presence of a heterocyclic ring (borabenzene) with a diffusion energy barrier of 0.039 eV increased the diffusion of Mg-ions. Therefore, B/N/P@oxTAM can be used as a viable anode material for MIBs with extended life cycle and quick charge-discharge rates due to its low open-circuit voltage and diffusion energy barrier, as well as its high theoretical specific capacity value.