Dimethyl sulfoxide-based electrolytes for rechargeable lithium batteries

Abstract

Mixed solutions of dimethyl sulfoxide (DMSO) and low viscosity solvents have been examined as a solvent of the electrolyte for rechargeable lithium (Li) batteries. The electrolytic conductivities of LiClO 4. LiBF 4 and LiPF 6 were measured as a function of the solvent composition. Maximum conductivities were observed in the DMSO concentration ranges of 60–80 mol% for LiClO 4 and LiBF 4, and 20–60 mol% for LiPF 6. The highest conductivity of all examined systems was 1.6 × 10 −2 S cm −1 in the solution containing 1,2-dimethoxyethane (DME) and LiPF 6 as the co-solvent and the electrolyte, respectively. Polarization behavior and charge-discharge characteristics of the lithium electrode were investigated in the DMSO-based solutions. The cycling efficiency was markedly dependent not only on the co-solvent but also the Li salt. The highest efficiency on the nickel substrate was observed in LiPF 6 (1 mol dm −3)/DMSO-DME (1:1 by volume). High rechargeability of Li was also expected in the solution containing LiClO 4 or LiBF 4 when aluminum was used as the substrate.