Theoretical investigation of Mo2CN2 MXene as anodes for Mg/ K/ Ca-ion batteries

The continued expansion of the global consumer electronics market has underscored the limited availability of lithium resources, prompting the development of alternative metal-ion battery technologies. Two-dimensional MXene materials have emerged as promising electrode candidates due to their exceptional electrical conductivity, high energy density, large specific surface area, and mechanical strength. The performance of N-functionalized Mo₂C as anodes for Mg, K, and Ca metal-ion batteries is investigated through first-principles calculations. Monolayer Mo₂CN₂ exhibits excellent metallic properties, structural stability, low diffusion barriers, and suitable open-circuit voltages. With multilayer adsorption, the maximum loading concentrations of Mg, K, and Ca on Mo₂CN₂ yield the stoichiometries Mo₂CN₂Mg₃.₅, Mo₂CN₂K₂.₅, and Mo₂CN₂Ca₄, corresponding to theoretical capacities of 809, 289, and 924 mA·h/g, respectively. These findings provide valuable insights for developing high-capacity, sustainable energy storage solutions.