Ion Exchange Composite Membranes for Non-Aqueous Redox Flow Batteries

In redox flow battery (RFB), a cell for generating electric energy has, like a fuel cell, a structure of cathode/ion exchange membrane/anode, and the catholyte and anolyte supplied to the cell via a pump contact corresponding electrodes, respectively. Non-aqueous electrolytes have higher electrochemical window and thus, these have been investigated for the electrolyte of RFB for higher energy density. In this study, we first adopt ion exchange composite membranes with ion conductive materials and hydrophilic supports as support matrixes, being chosen prevent the crossover of dual electrolytes and conduct the desired ions through the membrane. Especially, the membranes may have optimized ion mobility characteristics and electrochemical efficiency in a non-aqueous system, that is, an organic RFB system. The composite membranes have ionic conductivity of 0.1 mS/cm at room temperature in organic electrolytes and RFB single cell with the composite membrane shows relatively high coulombic and energy efficiencies with 90.4% and 81.8%.