The effect of strain on the Li-storage performance of V2C and Nb2C: From first-principles study. (May 2020)

• Record Type: Journal Article
• Authors: Wang, Hewen; Luo, Wenwei; Wu, Musheng; Ouyang, Chuying
• Is Part Of: Solid state communications. Volume 311(2020)
• Publication Date: 2020-05
• Subjects: MXenes -- Strain effect -- Li-ion batteries; Solid state chemistry -- Periodicals; Solid state physics -- Periodicals; Chimie de l'état solide -- Périodiques; Physique de l'état solide -- Périodiques; 530.41
• DOI: 10.1016/j.ssc.2020.113857
• Languages: English
• ISSNs: 0038-1098

Abstract

Abstract: Upon using 2-dimensional (2D) materials as electrodes for Li-ion batteries, strain will be produced due to mechanical factors and Li-intercalation reactions, which changes the intrinsic Li-ion storage performance of the 2D electrodes. In this paper, we investigate the effect of strain on the Li-storage performance of 2D MXenes V2 C and Nb2 C from density functional theory calculations. The Li-adsorption energies, Li-ion migration energy barriers at lithiated/delithiated states are calculated under varied external strain conditions ranging from −5% to 5%. It is found that, at low Li-ion adsorption concentration, compressive strain is beneficial for both Li-ion adsorption and diffusion, while at high Li-ion adsorption concentrations Li-ion adsorption becomes not favored on V2 C but favored on Nb2 C under compressive strain. Tensile strain is in favor of Li-vacancy diffusion at high Li-ion adsorption concentrations. Highlights: DFT calculations on the effect of strain on the Li-storage performance of 2D MXenes V2C and Nb2C. Compressive strain is beneficial for Li-ion adsorption and diffusion at low Li-ion adsorption concentration. Compressive strains don't favor Li-ion adsorption on V2C but favor on Nb2C at high Li-ion adsorption concentrations. Tensile strain is in favor of Li-vacancy diffusion at high Li-ion adsorption concentrations.