Determining and Minimizing Resistance for Ion Transport at the Polymer/Ceramic Electrolyte Interface

In this work, we report methods to quantify and minimize the interfacial resistance for Li ion transport, R interface, between a model polymer electrolyte, poly(ethylene oxide) + LiCF 3 SO 3 (PE), and a model Li + -conducting ceramic electrolyte, LICGC from Ohara Corporation. By constructing a PE–ceramic–PE trilayer cell, we found R interface to be very large, 1.2 kΩ·cm 2 at 30 °C, accounting for 66% of the total trilayer cell resistance. When dimethyl carbonate, a loose-binding solvent of Li +, was introduced into the trilayer, R interface decreased to essentially zero. As a result, a composite electrolyte with carbonate plasticizers wherein 40 vol % ceramic particles were dispersed in the polymer showed extraordinary room-temperature conductivity of approximately 10 –4 S/cm, 3 orders of magnitude higher than that of the dry composite electrolyte. This discovery can be used as guidance in designing composite electrolytes to achieve synergistic effects.