Exploring a metal coated by M-graphene as an encouraging anode electrode material for sodium-ion batteries using DFT calculations

Abstract

In the pursuit of advancing sodium-ion batteries (SIBs) technology as high-potential alternatives for lithium-ion batteries (LIBs), we were investigated the potential of M-graphene as an encouraging anode material using DFT-D calculations. The density of states (DOS) plot and band structure reveal that M-graphene with a zero-band gap indicates its metallic nature which is beneficial for electrical conductivity in redox reactions. The migration of sodium ions on the M-graphene surface was explored along two plausible paths. The calculated diffusion energy barrier indicated a remarkably low value of 0.29 and 0.27 eV, suggesting efficient ion migration. This kinetic favorability is critical for high-rate battery applications. Cohesive energy calculations were illustrated the thermodynamic stability of the adsorbed structure in different sodium concentrations. Ab initio molecular dynamics (AIMD) calculations demonstrated the thermal stability of fully adsorbed structure at 300 K. Furthermore, M-graphene demonstrates an impressive theoretical capacity of 1395 mAh g⁻¹, which is significantly higher than traditional anode materials. The average open-circuit voltage (OCV) is determined to be 0.79 V which is in the SIBs potential range. We found that although the induction of a defect in the structure does not change the metallic properties, it affects the adsorption behavior of M-graphene. These findings underscore M-graphene's substantial capacity and low energy barrier for ion diffusion, marking it as a viable candidate for high-performance SIBs.