Sc2C as a Promising Anode Material with High Mobility and Capacity: A First-Principles Study

Two-dimensional (2D) Sc2C, an example of a MXene, has been attracting extensive attention due to its distinctive properties and great potential in applications such as energy storage. In light of its high capacity and fast charging-discharging performance, Sc2C exhibits significant potential as an anode material for lithium- and sodium-ion batteries. Herein, a systematic investigation of Li/Na atom adsorption and diffusion on Sc2C planes was performed based on density functional calculations. The metallic character of pristine and adsorbed Sc2C ensures desirable electric conductivity, which indicates the advantages of 2D Sc2C for lithium- and sodium-ion batteries. A significant charge transfer from the Li/Na atoms to Sc2C is predicted, which indicates the cationic state of the adatoms. In addition, the diffusion barriers are as low as 0.018 and 0.012 eV for Li and Na, respectively, which illustrates the high mobility and cycling ability of Sc2C. In particular, each formula unit of Sc2C can adsorb up to two Li/Na atoms, which corresponds to a relatively high theoretical capacity of 462 or 362 mAhg(-1). The average electrode potential was calculated to be as low as 0.32 and 0.24 V for stoichiometric Li2Sc2C and Na2Sc2C, respectively, which makes Sc2C attractive for the overall voltage of the cell. Herein, our results suggest that Sc2C could be a promising anode candidate for both lithium-ion and sodium-ion batteries.