Studying Effects of Applying Strain and Doping Atoms On Li-Ion Transport Properties For Li 3 Obr 0.5 Cl 0.5 Anti-Perovskite Solid Lithium-Ion Electrolytes: Implications from Dft as Well as Aimd Calculations

Abstract

The effects of applying strain on the Li-ion transport properties of Li3OBr0.5Cl0.5 anti-perovskite solid lithium-ion electrolytes with different doping positions have been systematically studied within the framework of density functional theory. We have calculated the responses of bandgap, defect formation energy, Li-ion migration barrier under triaxial compression and tensile strains, ranging from -4% to 4%. Following, we have screened out Li3OBr0.5Cl0.5 (s6) with the highest conductivity at room temperature from our calculation of the diffusion and conductivity of different structures of Li3OBr0.5Cl0.5. Afterward, the changes of diffusion, conductivity and MSD of s6 under applying -4% and 4% triaxial strains have been studied. The results reveal intriguing implications: Tensile strains promote the defect formation energy of both Li-ion vacancy and Li interstitial, and reduce the migration barrier of Li-ion. Through the influences of the formation energy and migration barrier above, the conductivity of Li-ion has been improved significantly. This consequence is confirmed by AIMD simulation that the diffusivity and conductivity are enhanced under applying tensile strains, with a counteractive impact observed under applying compressive strains. These findings suggest that strains strongly affect Li-ion conductivities in Li3OBr0.5Cl0.5 anti-perovskite electrolytes, and applying tensile strain can be a potential method to enhance lithium transport.

Keywords: Strain, Doping, Solid electrolyte, Anti-perovskite, Li-ion migration, Li-ion conductivity