Characteristics of Sulfolane‐Based Electrolytes for Rechargeable Lithium Batteries

Abstract

The utility of sulfolane (S)-based electrolytes has been studied for rechargeable lithium batteries. Electrolytic conductivities of LiC1O 4 LiBF 4 and LiPF 6 were measured in the mixed system of S with 1, 3-dioxolane (DOL), tetrahydro-furan (THF), or 1, 2-dimethoxyethane (DME). Vapor pressure, viscosity, and relative permittivity of the mixed solvents and/or the electrolytic solutions were also measured, and the results were discussed in connection with the solution conductivity. Conductivity maxima were observed in the mixed solutions containing 60–90 mole percent ethers. The conductivity of S-DME (1:9 by volume)/LiPF 6 (1M), being the highest of all examined, was 1.5 x 10 –2 S-cm -1 . The Li cycling characteristics were mainly investigated in the S-ether (1:1) mixed solutions. Efficiencies on the Ni substrate in the S-DME solutions varied less with cycling than those in S-DOL and S-THF. The average efficiency of Li cycling in S-DME increased in the order of LiC1O 4 < LiBF 4 < LiPF 6 . The Li cycling characteristics in the S-ether solutions are discussed from the standpoints of ionic behavior in the solution and chemical reaction at Li-solution interface. © 1985, The Electrochemical Society, Inc. All rights reserved.