In this study, the hydrogen/iron redox flow cell was evaluated in order to estimate its potential as an energy-storage system. The system was studied for the first time, for energy-storage applications, with electrolytes composed of several different iron salts and their conjugate acids. Cell performance varied with electrolyte composition. Best results were obtained with a solution of iron sulfate in sulfuric acid: stable performance, good capacity utilization, energy-conversion efficiency of up to 82% and a power density of up to 0.27W cm(-2), with no optimization of cell components. The results show the potential of the hydrogen/iron system as a candidate for energy-storage and further optimization should greatly enhance performance. (C) 2013 Elsevier B.V. All rights reserved.