Liu, YahuaGoulet, Marc-AntoniTong, LiuchuanLiu, YazhiJi, YunlongWu, LiangGordon, RoyAziz, MichaelYang, ZhengjinXu, Tongwen2021-04-212019-07Liu, Yahua, Goulet, Marc-Antoni, Tong, Liuchuan, Liu, Yazhi, Ji, Yunlong, Wu, Liang, Gordon, Roy G, Aziz, Michael J, Yang, Zhengjin, and Xu, Tongwen. "A Long-Lifetime All-Organic Aqueous Flow Battery Utilizing TMAP-TEMPO Radical." Chem 5, no. 7 (2019): 1861-870.2451-9294https://nrs.harvard.edu/URN-3:HUL.INSTREPOS:37367352The massive-scale integration of renewable electricity into the power grid is impeded by its intrinsic intermittency. The aqueous organic redox flow battery (AORFB) rises as a potential storage solution; however, the choice of positive electrolytes is limited, and the aqueous-soluble organic positive redox-active species reported to date have short lifetimes. Here we report a stable organic molecule for the positive terminal, 4-[3-(trimethylammonio)propoxy]-2,2,6,6- tetramethylpiperidine-1-oxyl (TMAP-TEMPO) chloride, exhibiting high (4.62 M) aqueous solubility. When operated in a practical AORFB against a negative electrolyte comprising BTMAP-viologen at neutral pH, the flow cell displayed an open-circuit voltage of 1.1 Volts and a coulombic efficiency of >99.73%. The capacity retention rate is among the highest of all-organic AORFBs reported to date, at 99.993% per cycle over 1000 consecutive cycles; the temporal capacity fade rate of 0.026% per hour is independent of concentration.en-USMaterials ChemistryBiochemistryGeneral ChemistryGeneral Chemical EngineeringBiochemistry, medicalEnvironmental ChemistryJournal Article2021-04-2110.1016/j.chempr.2019.04.021