Iron-based redox flow batteries are promising and low-cost energy storage technologies for grid level showing the potential to meet DOE’s cost targets LCOS, $0.05/kWh due to its natural abundancy and eco friendliness. Iron deposition process has a parasitic hydrogen evaluation reaction (HER) controlling the storage capacity and efficiency. HER reaction imbalances the electrolyte composition and causes durability issues. Our present study shows how the performance of the iron flow battery can be increased by introducing advanced 3D electrodes and engineered electrolytes.This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. Funding was provided by Lawrence Livermore National Laboratory Directed Research and Development (LDRD) Grant 22-DR-014. IM release number: LLNL-ABS-858432