Jin, ShijianJing, YanKwabi, DavidJi, YunlongTong, LiuchuanDe Porcellinis, DianaGoulet, Marc-AntoniPollack, Daniel A.Gordon, RoyAziz, Michael2020-12-082019Jin, Shijian, Yan Jing, David G. Kwabi, Yunlong Ji, Liuchuan Tong, Diana De Porcellinis, Marc-Antoni Goulet, Daniel A. Pollack, Roy G. Gordon, and Michael J. Aziz. "A Water-Miscible Quinone Flow Battery with High Volumetric Capacity and Energy Density." ACS Energy Letters 4, no. 6 (2019): 1342-348.2380-81952380-8195https://nrs.harvard.edu/URN-3:HUL.INSTREPOS:37366505A water-miscible anthraquinone with polyethylene glycol (PEG)-based solubilizing groups is introduced as the redox-active molecule in a negative electrolyte (negolyte) for aqueous redox flow batteries, exhibiting the highest volumetric capacity among aqueous organic negolytes. We synthesized and screened a series of PEG-substituted anthraquinones (PEGAQs) and carefully studied one of its isomers, namely 1,8-bis(2-(2-(2- hydroxyethoxy)ethoxy)ethoxy)anthracene-9,10-dione (AQ-1,8-3E-OH), which has high electrochemical reversibility and is completely miscible in water of any pH. A negolyte containing 1.5 M AQ-1,8-3E-OH, when paired with a ferrocyanide-based positive electrolyte across an inexpensive, non-fluorinated permselective polymer membrane at pH 7, exhibits an open-circuit potential of 1.0 V, a volumetric capacity of 80.4 Ah/L, and an energy density of 25.2 Wh/L.en-USJournal Article2020-12-0810.1021/acsenergylett.9b00739