Unravelling the dynamics of g-C₃N₄ monolayer as a potential anode for sodium-ion storage: A first-principles study

The present work employs first principles analysis to study the electrochemical dynamics of the tri-s-triazine g-C₃N₄ monolayer for its potential application as an anode in sodium-ion batteries. Initially, we perform first-principles simulations to examine four possible sodium adsorption sites on g-C₃N₄: Top of Carbon (T_C), Top of Nitrogen (T_N), Bridge site between Carbon and Nitrogen (B_C-N), and Hollow site between Carbon and Nitrogen (H_C-N). According to our findings, sodium adsorption causes an increase in the bandgap, and for the adsorption site concern, the H_C-N site is the most energetically favorable site. The material tri-s-triazine g-C₃N₄ exhibits a good open circuit voltage of 1.36 V, a high storage capacity of 1455.47 mAh/g, and a low diffusion barrier of 0.292 eV, which allows rapid charge-discharge cycles. Ab initio molecular dynamics simulation is performed on g-C₃N₄ to verify the thermal stability at 500 K during sodium adsorption. These results suggest favorable electrochemical performance, effective charge transfer, and structural stability of g-C₃N₄ is a promising SIB anode material.