2D Co-anti-MXenes (CoB/CoP) as promising anode materials for magnesium-ion batteries in diglyme and triglyme electrolytes: a first-principles study†

Abstract

Magnesium-ion batteries have the potential to replace commercially available Li-ion batteries in the future due to their lower cost and sustainability. On the other hand, magnesium ions are dendrite-free and offer greater energy density and volumetric capacity due to their divalent nature. Conventional electrode materials face challenges in capturing magnesium ions. We assessed the feasibility of using Co-anti MXene (CoB/CoP) monolayers as electrode materials for Mg-ion batteries using density functional theory. The adsorption energy of CoB for Mg atoms is −2.88 eV in a vacuum (−4.46 and −4.55 eV for diglyme and triglyme effects calculated using the Vaspsol method), respectively. As predicted by ab initio molecular dynamics, Mg₈Co₁₈B₁₈ shows high stability at 300 K in the magnesium process. A diffusion coefficient of 3.57 × 10⁻⁷ cm² s⁻¹ was determined at an ambient temperature of 300 K. The electrical conductivity per relaxation time (Mg₈Co₁₈B₁₈) at 300 K is found to be 1.64 × 10¹⁹ Ω⁻¹ m⁻¹ s⁻¹ with a corresponding chemical potential of −6.94 eV, respectively. The Co-anti MXenes have the potential to be used as anode materials in Mg-ion batteries.