Solvent-Free Composite PEO-Ceramic Fiber/Mat Electrolytes for Lithium Secondary Cells

Abstract

Solvent-free composite poly(ethylene oxide) (PEO)-ceramic fiber or mat electrolytes with high ionic conductivity and good interfacial stability have been developed using high-ionic-conductivity La0.55Li0.35TiO3La0.55Li0.35TiO3 fibers and mats. The conducting ceramic fibers can penetrate the cross section of the electrolyte film to provide long-range lithium-ion transfer channels, thus producing composite electrolytes with high conductivity. In this work, a maximum room-temperature conductivity of 5.0×10−45.0×10−4 S cm⁻¹ was achieved for 20 wt % La0.55Li0.35TiO3La0.55Li0.35TiO3 fiber in a PEO- LiN(SO2CF2CF3)2LiN(SO2CF2CF3)2 mixture containing 12.5 wt % Li+Li+ in PEO. The maximum transference number obtained was 0.7. The ceramic fibers in this composite electrolyte are coated by a very thin PEO layer, which is sufficient to provide good interfacial stability with lithium-ion and lithium-metal anodes. © 2004 The Electrochemical Society. All rights reserved.