A low-cost sulfate-based all iron redox flow battery

Redox flow batteries (RFBs) are promising choices for stationary electric energy storage. Nevertheless, commercialization is impeded by high-cost electrolyte and membrane materials. Here, we report a low-cost all-iron RFB that features inexpensive FeSO4 electrolytes, microporous along with glass fiber separator. The addition of 0.1 м 1-ethyl-3-methylimidazolium chloride (EMIC) overcomes the low solubility in water which raised to 2.2 м. DFT calculations demonstrate EMI+ can strengthen interaction between sulfate anions molecules. This composition also allows both anode cathode reactions operate without actively maintaining pH gradient them, thus eliminating need expensive ion exchange membranes. demonstrates stable operation at current density 20 mA cm−2 more than 800 cycles via simple, periodic regeneration process. Furthermore, system cost FeSO4/EMIC RFBs projected be $ 50 per kWh due its active materials membrane. low-cost, high-concentration energy‐storage storing renewable energy.