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Phenylene‐Bridged Bispyridinium with High Capacity and Stability for Aqueous Flow Batteries
Author(s) -
Hu Shuzhi,
Li Tianyu,
Huang Mingbao,
Huang Jinghua,
Li Wenjin,
Wang Liwen,
Chen Zhenqiang,
Fu Zhiyong,
Li Xianfeng,
Liang Zhenxing
Publication year - 2021
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202005839
Subject(s) - materials science , pyridinium , phenylene , electrolyte , delocalized electron , redox , flow battery , ring (chemistry) , chemical engineering , combinatorial chemistry , chemistry , organic chemistry , electrode , engineering , composite material , polymer , metallurgy
A rotating phenyl ring is introduced between the two pyridinium rings, namely, 1,1′‐bis[3‐(trimethylamonium)propyl]‐4,4′‐(1,4‐phenylene)bispyridinium tetrachloride ((APBPy)Cl 4 ), to form a switchable conjugation. In this design, the conjugation is switched “off” in the oxidized state and the two pyridinium rings behave independently during the redox process, yielding a concomitant transfer of two electrons at the same potential and, thus, simplifying the battery management. The conjugation is switched “on” in the reduced state and the charge can be effectively delocalized, lowering the Lewis basicity and improving its chemical stability. By pairing 0.50 m (APBPy)Cl 4 with a 2,2,6,6‐tetramethylpiperidin‐1‐yl oxyl derivative as the positive electrolyte, a flow battery delivers a high standard cell voltage of 1.730 V and a high specific capacity of 20.0 Ah L –1 . The battery also shows an exceptionally high energy efficiency of 80.8% and a superior cycling stability at 80 mA cm –2 . This strategy proves itself a great success in engineering viologen as a two‐electron storage mediator with high capacity and stability.