Large-scale energy storage systems are crucial for substantial deployment of renewable energy sources. Energy storage systems with high energy density, high safety, and low cost and environmental friendliness are desired. To overcome the major limitations of the current aqueous redox flow battery systems, namely lower energy density (~25 Wh L-1) and presence of strong acids and/or other hazardous, a high energy density aqueous zinc/polyiodide flow battery (ZIB) is designed with near neutral ZnI2 solutions as catholytes. The energy density of ZIB could reach 322 Wh L-1 at the solubility limit of ZnI2 in water (~7 M). We demonstrate charge and discharge energy densities of 245.9 Wh/L and 166.7 Wh L-1 with ZnI2 electrolyte at 5.0 M, respectively. The addition of ethanol (EtOH) in ZnI2 electrolyte can effectively mitigate the growth of zinc dendrite at the anode and improve the stability of catholytes with wider temperature window (-20 to 50°C), which enable ZIB system to be a promising alternative as a high-energy and high- safety stationary energy storage system.
Revised: August 28, 2020 |
Published: February 24, 2015
Citation
Li B., Z. Nie, M. Vijayakumar, G. Li, J. Liu, V.L. Sprenkle, and W. Wang. 2015.Ambipolar zinc-polyiodide electrolyte for a high-energy density aqueous redox flow battery.Nature Communications 6.PNNL-SA-103966.doi:10.1038/ncomms7303