High-energy and low-cost membrane-free chlorine flow battery

• Published in: Nature communications Vol. 13; no. 1; pp. 1281 - 8
• Main Authors: Hou, Singyuk, Chen, Long, Fan, Xiulin, Fan, Xiaotong, Ji, Xiao, Wang, Boyu, Cui, Chunyu, Chen, Ji, Yang, Chongyin, Wang, Wei, Li, Chunzhong, Wang, Chunsheng
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 11.03.2022; Nature Publishing Group; Nature Portfolio
• Subjects: 140/133; 147/135; 639/166/4073/4071; 639/4077/4079/891; Carbon tetrachloride; Chlorine; Electric power transmission; Electrolysis; Electrolytes; Energy efficiency; Energy storage; Flow; Flux density; Humanities and Social Sciences; Immiscibility; Low cost; Membranes; Metal ions; Miscibility; multidisciplinary; Rechargeable batteries; Redox reactions; Renewable energy; Saline water; Science; Science (multidisciplinary); Sodium chloride; Storage batteries; Transition metals
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-022-28880-x

Grid-scale energy storage is essential for reliable electricity transmission and renewable energy integration. Redox flow batteries (RFB) provide affordable and scalable solutions for stationary energy storage. However, most of the current RFB chemistries are based on expensive transition metal ions or synthetic organics. Here, we report a reversible chlorine redox flow battery starting from the electrolysis of aqueous NaCl electrolyte and the as-produced Cl 2 is extracted and stored in the carbon tetrachloride (CCl 4 ) or mineral spirit flow. The immiscibility between the CCl 4 or mineral spirit and NaCl electrolyte enables a membrane-free design with an energy efficiency of >91% at 10 mA/cm 2 and an energy density of 125.7 Wh/L. The chlorine flow battery can meet the stringent price and reliability target for stationary energy storage with the inherently low-cost active materials (~$5/kWh) and the highly reversible Cl 2 /Cl − redox reaction. Flow batteries provide promising solutions for stationary energy storage but most of the systems are based on expensive metal ions or synthetic organics. Here, the authors show a chlorine flow battery capitalizing the electrolysis of saltwater where the redox reaction is stabilized by the saltwater-immiscible organic flow.