English Abstract

Blend and Composite Materials based on Solid Polymer Electrolytes

Department of Organic and Polymer Materials Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan
Nippon Gomu Kyokaishi,(2012),85(3),93-100 General Review in Japanese

Solid polymer electrolytes (SPE) are proposed as solid state alternatives to liquid electrolytes in future electrochemical applications, such as lithium-ion batteries and dye-sensitized solar cells. The SPE however suffer from relatively low ionic conductivity in the solid state compared with most liquid, gel and ceramic electrolytes. Migration of ions in SPE can be realized by increasing local chain mobility of polyether, since ions are transported via the segmental motion. Unfortunately, cation-dipole interactions sometimes inhibit migration of ions because of their strong cohesion, that increases the glass transition temperature (Tg). Therefore, novel techniques that are not depend on the salvation and mobility of polyether are needed for the fast migration of ions. Here, two techniques (polymer blend and composite) are introduced as one of solutions for the SPE. In previous studies, simple polyether-, polyanion- and elastomer-based SPE blends have mainly been reported, but it was difficult to increase conductivity more than 10-5 S cm-1. On the other hand, addition of fillers to the SPE is another noteworthy technique, because this can give rise to the significant increase in conductivity, the inhibition of polymer re-crystallization, the decrease in Tg, and the increase in cation transport number. In this review, we prepared NBR/polyether electrolyte blends as novel electrostatic materials, synthesized hexagonally ordered mesoporous silica and used freeze-dried clay as novel inorganic fillers.

Keywords: Solid polymer electrolyte, Ionic conductivity, Lithium-ion battery, Polymer blend, Composite, Mesoporous silica, Clay