Theoretical Investigation of 2D M₃C₂S₂ (M = Cr, Zr) as Potential Electrode Materials for Li-Ion Batteries

Herein, the electronic and magnetic properties of 2D M3C2S2 (M = Cr, Zr) monolayers and their potential as lithium-ion battery electrodes are systematically studied by density functional theory (DFT). The geometric structures of the M3C2S2 monolayers are both thermally and dynamically stable. The Cr3C2S2 monolayer acts as a magnetic metal, while the Zr3C2S2 monolayer shows a nonmagnetic metallicity nature. The diffusion energy barriers are only 0.23 eV (Cr3C2S2) and 0.26 eV (Zr3C2S2), and lithium storage capacities are 439.35 mA h g(-1) for the Cr3C2S2 monolayer and 296.41 mA h g(-1) for the Zr3C2S2 monolayer, respectively. Compared with the pristine M3C2 monolayers, although the diffusion energy barriers are slightly increased after the S group modification, the lithium storage capacity of Cr3C2S2 and Zr3C2S2 monolayers both have obvious improvement. Our work indicates that the S-functionalized M3C2S2 hold promise for future use as electrode materials for Li-ion batteries.