First-principles calculation of electronic properties and diffusion barriers of Sc2CCl2 and Sc2CF2 for metal (Li, Na, K) ion batteries

Abstract

MXenes have emerged as promising candidate for energy storage devices because of their superior properties. In this work, the electronic properties, low open circuit voltage (OCV) and diffusion barrier of Li, Na, K adsorption on Sc2CCl2 and Sc2CF2 monolayers are investigated by density functional theory. The most stable adsorption site is confirmed because of the shortest adsorption height and largest adsorption energy. The adsorptions of Li/Na/K on Sc2CCl2 and Sc2CCF2 induce the semiconductor–metal transition. Na-Sc2CF2 and Li-Sc2CF2 have higher theoretical capacity (CM), low open circuit voltage (OCV) and diffusion barriers, so they are more suitable as anode materials for Na-ion and Li-ion batteries. The analysis of charge transfer indicates that the adsorbed atoms in Sc2CF2 monolayer lose more electrons than the adsorbed atoms in Sc2CCl2 system because of stronger electronegativity of F.