A Zinc-Iron Redox Flow Battery for High-Performance and Low-Cost Energy Storage

Redox flow batteries are considered the most promising scalable technology for the storage of renewable wind and solar electricity. We have developed a new double-membrane triple-electrolyte concept that offers unprecedented freedom in choosing redox pairs and the pH of the electrolytes [1-3].  We have demonstrated a Zn-Ce flow battery that offers a 3.1 V cell voltage, the highest for an aqueous flow battery, and a S-Fe flow battery that is very inexpensive because S and Fe are the 5^th and 1^st most produced element, respectively. In this presentation, we show a new Zn-Fe flow battery that can deliver a peak power density of 647 mW/cm² and cycle at a current density of 100 mA/cm² with a round trip efficiency of 70%. Our state-of-the-art cost model shows that this Zn-Fe flow battery can meet the cost target of $100/kWh for commercialization.

[1] Shuang Gu,   Ke Gong,   Emily Z. Yan and   Yushan Yan, A multiple ion-exchange membrane design for redox flow batteries, Energy Environ. Sci., 2014, DOI: 10.1039/C4EE00165F

[2] Y.S. Yan, S. Gu, K. Gong, Double-membrane triple-electrolyte redox flow battery design, Application No.: 13/918444, Publication date: 01/02/2014

[3] Y.S. Yan, S. Gu, K. Gong, Multiple-membrane multiple-electrolyte redox flow battery design,  Application No.: 13/918452, Publication date: 01/02/2014