N-methylphenothiazine as stable and low-cost catholyte for nonaqueous organic redox flow battery. (May 2023)

• Record Type: Journal Article
• Authors: Tegegne, Belay Getahun; Kabtamu, Daniel Manaye; Li, Yu-Zhen; Ou, Yun-Ting; Huang, Zih-Jhong; Hsu, Ning-Yih; Ku, Hung-Hsien; Wang, Yao-Ming; Wang, Chen-Hao
• Is Part Of: Journal of energy storage. Volume 61(2023)
• Publication Date: 2023-05
• Subjects: N-methylphenothiazine -- 2, 1, 3-Benzothiadiazole -- Redox flow battery -- Non-aqueous electrolyte -- Catholyte; Energy storage -- Periodicals; Energy storage -- Research -- Periodicals; 621.3126
• DOI: 10.1016/j.est.2023.106753
• Languages: English
• ISSNs: 2352-152X

Abstract

Abstract: This work uses a highly durable, environmentally friendly, and low-cost catholyte of N -methylphenothiazine (MPT), which is a heterocyclic compound containing nitrogen and sulfur for a non-aqueous organic redox flow battery (NAORFB). By coupling MPT with 2, 1, 3-benzothiadiazole (BTD)-based electrolyte (BTD/MPT), it delivers the open-circuit voltage (OC V ) of 2.23 V. The average coulombic efficiency of the NAORFB using redox-active materials of BTD/MPT reaches 99.5% over 50 cycles. This high coulombic efficiency is the best indicator of the stability of such redox-active materials of BTD/MPT. The outstanding stability is attributed to two benzene rings and one methyl group attached to the N-atom active center of N -methylphenothiazine. These groups stabilize the radical cation by releasing electrons and shielding against nucleophilic attack. Graphical abstract: Unlabelled Image Highlights: The non-aqueous organic redox flow battery (NANORFB) has a wide potential of 2.23 V. The NANORFB uses BTD/MPT as the redox active materials. The NANORFB reaches 99.5% over 50 cycles of the coulombic efficiency. Our first work identified the compatible supporting electrolyte for BTD and MPT mixture.