The hybrid hydrogen-vanadium reversible fuel cell consists of a gaseous hydrogen fuel cell electrode and a liquid vanadium flow battery electrode. This hybrid fuel cell system offers a feasible solution for storing electrical energy from the grid or directly from renewable energy sources such as wind and solar. This system is attractive over the all-vanadium system due to the 50% reduction in the amount of vanadium solution required. Furthermore, by replacing the negative vanadium electrode with a hydrogen electrode the effect of self-discharge by the crossover of unwanted ions (vanadium II and III) from the negative electrode to the positive electrode is eliminated. Another benefit of this two-phase hybrid system is the ease of separation of the cross-over species. In this presentation, the effects of operating and design variables such as the vanadium electrolyte flow rate, type of carbon electrodes, and Nafion membranes and electrospun membranes made of perfluorosulfonic acid (PFSA)/ polyvinylidene fluoride (PVDF), which are developed to reduce the crossover rate of vanadium ions, with different thickness will be discussed.

Acknowledgement

The work presented was partially funded by the National Science Foundation under Grant No. EFRI-1038234.