Intercalation and de-intercalation mechanism in lithium metal fluorosulfate-based half-cell and full-cell configurations: a DFT study

Abstract

Li-ion diffusion, intercalation, and de-intercalation are key challenges in lithium metal fluorosulfate for the evolution of the electrochemical properties of LIBs. Here, we addressed a novel and viable protocol for the evolution of the Li-ion migration and electrochemical properties of lithium metal fluorosulfate using first-principles calculations. The electronic properties of lithium metal fluorosulfate disclosed the band-gap tuning through Cr, Mn, and Ni substitution. The diffusion of Li ions from one octahedral position to another, following the one-dimensional pathway along the c-axis, was disclosed by the charge density and distribution analysis. The investigation of thermal properties unveiled the intercalation and deintercalation, which elaborated the chemical energy, structural changes, and spontaneous behavior. The Li/LFCS half-cell electrochemical properties predicted an average operating voltage of 4.99 V, and the oxidation and reduction potentials of Li/LFCS were 2.2 V and 1.95 V, respectively. The volumetric energy and power densities of the Li/LFCS half-cell were 1.15 W h cm⁻³ and 1.15 W cm⁻³, respectively. The gravimetric energy and power densities of the Li/LFCS half-cell were 3.109 kW h kg⁻¹ and 3.109 kW kg⁻¹, respectively. The theoretical capacity of Li/FCS was 220.3 mA h g⁻¹. The average voltage of the C₆/LFCS full-cell was 4.31 V. The calculated energy and power densities of C₆/LFCS were 3.109 kW h kg⁻¹ and 3.109 kW kg⁻¹, respectively.