Ion Transport in Temperature-Resistant Ceramic-Based Composites

Polymer-based membranes have been widely investigated as ion transport media for energy storage devices. However, they lack dimensional and mechanical stability at higher temperatures, limiting their operating range. Room Temperature Ionic Liquids (RTILs) are an attractive class of electrolyte with high thermal and electrochemical stability. Negligible values of vapor pressure and reasonable ionic conductivities suggest that they are serious candidates to feature as a role component in designing temperature-robust devices. The challenges for temperature-resistant technologies lie around properly immobilizing the liquid electrolyte. In the present work a temperature-stable ion-conductive composite membrane is designed by combining RTILs with ceramic supports, as bentonite clay. The role of the ceramic material is to effectively offer mechanical support while absorbing and retaining the electrolyte. The ionic conductivity of composites with different contents of ceramic and RTIL were investigated and they were found to be appropriate for operation between room temperature and at least 150 ^oC. Such composites are a good alternative for high temperature applications where ionic conductivity is required.