Theoretical prediction of adsorption and diffusion of sodium on layered CoSe: A first-principles investigation

Energy storage technologies are essential for modern applications, with batteries being the most common solution. However, the increasing demands of today's rapidly evolving society highlight the need for next-generation battery materials that offer higher energy density, longer lifespan, lower cost, and improved safety. To meet these requirements, researchers are actively investigating novel materials and alternative battery systems. A clear understanding of their underlying electrochemical processes is crucial for transitioning these innovations into practical applications. In this work, first-principles calculations are performed to investigate the suitability of a two-dimensional CoSe monolayer as an anode material for Na-ion batteries, with the objective of evaluating its potential for energy storage applications. Our simulations show that the pristine and Na-adsorbed CoSe systems exhibit metallic behavior, thereby yielding excellent electronic conductivity and a low activation energy barrier of 0.33 eV, which facilitates efficient sodiation and desodiation. Notably, the adsorbed NaCoSe monolayer offers several stable adsorption sites, leading to a high theoretical capacity of 583.09 mA hg −1 and a low average open-circuit voltage of 0.88 V, respectively. This study offers key insights into optimizing anode materials for enhanced Na-ion battery performance. High Na storage capacity, suitable voltage profile, and high electronic conductivity designate CoSe as an outstanding anode for SIBs. • The intrinsic Na-storage mechanism of 2D CoSe is investigated. • Both pristine and Na-adsorbed CoSe exhibit metallic behavior, ensuring excellent electronic conductivity. • A low Na-ion diffusion energy barrier of 0.33 eV enables fast sodiation and desodiation kinetics. • Multiple Na sites yield high capacity (583.09 mA h g −1 ) and a low average open-circuit voltage of 0.88 V.