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, Rinterface, between a model polymer electrolyte, poly(ethylene oxide) + LiCF3SO3 (PE), and a model Li+-conducting ceramic electrolyte, LICGC from Ohara Corporation. By constructing a PE–ceramic–PE trilayer cell, we found Rinterface to be very large, 1.2 kΩ·cm2 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, Rinterface 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.