PNNL

Abstract

The newly developed Fe/V redox flow battery has demonstrated attractive cell performance. However, the deliverable energy density is relatively inferior due to the low cell voltage. To compensate this disadvantage and compete with other redox flow battery systems, cost reduction of the Fe/V system is necessary. This paper describes evaluation of hydrocarbon-based Daramic® microporous separators for use in the Fe/V system. The separator B having ion exchange capacity demonstrated excellent capacity retention capability. Separator B exhibited energy efficiency above 65% over a broad temperature range of 5-50oC and at current densities up to 80mA/cm2. Plus, separator B is very inexpensive and has exceptional mechanical properties. Therefore, this separator shows great potential to replace the expensive Nafion® membrane. This will drive down the capital cost and make the Fe/V system a promising low-cost energy storage technology.