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 membrane along with a glass fiber separator. The addition of 0.1 м 1-ethyl-3-methylimidazolium chloride (EMIC) overcomes the low solubility of FeSO4 in water which is raised to 2.2 м. DFT calculations demonstrate that EMI+ can strengthen the interaction between sulfate anions and water molecules. This electrolyte composition also allows both anode and cathode reactions to operate without actively maintaining a pH gradient between them, thus eliminating the need for expensive ion exchange membranes. The all-iron RFB demonstrates stable operation at a current density of 20 mA cm–2 for more than 800 cycles via a simple, periodic regeneration process. Furthermore, the system cost of FeSO4/EMIC RFBs is projected to be $ 50 per kWh due to its low-cost active materials and the inexpensive microporous membrane. Finally, this low-cost, high-concentration all-iron RFB is a promising stationary energy–storage system for storing renewable energy.
- Research Organization:
- Univ. of Colorado, Boulder, CO (United States)
- Sponsoring Organization:
- USDOE Advanced Research Projects Agency - Energy (ARPA-E)
- Grant/Contract Number:
- AR0000770
- OSTI ID:
- 1977391
- Journal Information:
- Journal of Power Sources, Vol. 513, Issue C; ISSN 0378-7753
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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