Influence of mixed electrolyte on the performance of Iron-ion/Hydrogen redox flow battery
ECS Electrochemistry Letters
Department of Chemical and Biomedical Engineering, Florida A and M University, Tallahassee, FL, United States; Department of Environmental Engineering, University of Oklahoma, Norman, OK, United States; Department of Chemical Engineering, Federal Universi
Improved charge/discharge performance of Iron-ion/Hydrogen redox flow battery (RFB) electrolyte with a mixed FeSO<inf>4</inf> and FeCl<inf>2</inf> is reported. Addition of Cl- ions into a sulfate electrolyte changes the charge/discharge behavior of the sulfate electrolyte leading to a reduction in charging potential for a mixed FeSO<inf>4</inf> and FeCl<inf>2</inf> electrolyte system. This suggests that a sulfate/chloride electrolyte system can lead to improved charge/discharge of the Fe-ion/H<inf>2</inf> RFB. Reverse addition of FeSO<inf>4</inf> to FeCl<inf>2</inf> showed a decrease in the mixed electron transfer efficiency (experimental current relative to theoretical) equivalent to a decrease in electrolyte performance. We deduce that 0.8 M FeCl<inf>2</inf> corrosive electrolyte can be replaced by less corrosive mixture of 46 mol % Cl- in 0.8 M FeSO4 to achieve the same performance that can be obtained using an all chloride system. © The Author(s) 2015. Published by ECS.
Chlorine compounds; Electric batteries; Electrolytes; Ions; Metal ions; Secondary batteries; Sulfur compounds; Charge/discharge performance; Corrosive electrolytes; Electrolyte systems; Electron-transfer efficiency; Mixed electrolyte; Redox flow batteries; Reverse addition; Sulfate electrolytes; Flow batteries