Correlating Nafion Membrane Microstructure with Vanadium Redox Flow Battery Performance

This presentation describes the correlation established between the Nafion membrane microstructure and the vanadium redox flow battery performance. The impact of the equivalent weight on the microstructure of the membrane and thus the performance of VRBs is systematically studied. By tailoring the equivalent weight and membrane thickness, the new membrane contains optimal pore geometry with extremely low vanadium-ion permeability was developed. In addition, its area resistance is comparable to, and its cost is significantly less than, the widely used Nafion 115 membrane. Excellent VRB single-cell performance (89.3% energy efficiency at 50mA∙cm^-2) was achieved along with a stable cyclical capacity over prolonged cycling (>200 cycles). The chemical composition, pore geometry, transport properties and flow cell performance will be reported.