Effects of Crown Ether Addition to Organic Electrolytes on the Cycling Behavior of the TiS2 Electrode

Abstract

The characteristics of the rechargeable cell utilizing propylene carbonate (PC)‐based electrolytes have been investigated. Some effects of the addition of crown ethers to the electrolyte have been observed. The addition of 12‐crown‐4 improved the discharge capacity and the rechargeability of the cell, whereas the addition of 15‐crown‐5 showed a rather negative effect on the cycling performance. The chemical analysis of the discharged cathode (positive electrode) indicated that the amount of intercalated Li during the discharge from tends to be in excess of that calculated from Faraday's law. The x‐ray diffraction analyses of the discharged and the partially recharged cathodes suggested that the discharge reaction of the electrode involved solvent cointercalation (i.e., cointercalation of 12‐crown‐4 from the crown ether‐added electrolyte, and perhaps PC from ). The size and the strength of the Li+‐solvate (Li+‐complex) in the solution seem to be critical parameters of the solvent effects on the charge‐discharge characteristics of the cell.