Rational design of h-AlC monolayer as anode material for Mg-ion battery: A DFT study

In the present work, we have analyzed the suitability of two-dimensional (2D) h-AlC as a high-capacity anode material for Mg-ion batteries (MIBs) by employing first principles-based density functional theory (DFT). The structural parameters, electronic band structure, partial density of states (PDOS), theoretical storage capacity (TSC), diffusion energy barrier (DEB), open-circuit voltage (OCV), and room temperature stability (from ab initio molecular dynamic (AIMD) simulations) are calculated and discussed. The band structure of h-AlC monolayer remains metallic for all considered adsorption concentrations of Mg-atoms which indicates its good electrical conductivity. A significant quantity of charge is transferred from Mg atom to h-AlC during adsorption of the Mg atom due to its lower electronegativity compared with the Al and C atoms. The calculated TSC is 1221.75 mAh g(-1) which is higher than many anode materials. For MIBs, calculated DEB and OCV are 1.21 and 0.73 V, respectively. However, transition from planar structure to buckled structure takes place during the adsorption of more than 9 Mg-atoms over h-AlC. The lattice change is negligible during adsorption of Mg atoms. The AIMD calculations revels that the 9 and 18 Mg atoms adsorbed h-AlC is stable at T = 300 K. The aforementioned findings suggest that h-AlC can be anode material for MIBs.