Radical Charge Population and Energy: Critical Role in Redox Potential and Cycling Life of Piperidine Nitroxyl Radical Cathodes in Aqueous Zinc Hybrid Flow Batteries

Release Time:2025-04-30  Hits:

• Date:2025-04-30
• Title of Paper:Radical Charge Population and Energy: Critical Role in Redox Potential and Cycling Life of Piperidine Nitroxyl Radical Cathodes in Aqueous Zinc Hybrid Flow Batteries
• Journal:ACS Appl. Mater. inter.
• Summary:Redox-active 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) derivatives have recently been investigated to expand the choice of catholyte for aqueous flow batteries (AFBs). However, the effects of substituent R in 4-position on redox potential and corresponding capacity fading mechanism are still unclear. Here, we conduct comparative studies of four R-TEMPO with R = -OH, -NH2, -COOH, and -NHCOCH3 in zinc hybrid AFBs. Experimental and theoretical analyses reveal that low-radical head charge population sum and radical energy, depending on R in 4-position, play a critical role in enhancing redox potential and cycling life of R-TEMPO. The electronic effect brought along by N-acetyl could redistribute the charge and lower systematic energy, making the ring-opening joint sturdy and therefore suppress the side reactions. Accordingly, the 4-NHCOCH3-TEMPO/Zn battery achieves a high capacity retention of >99.65%/day and an open-circuit voltage of 1.71 V. Our findings on the effects of substituent are greatly anticipated to boost the high-energy density, long-life, and eco-friendly TEMPO-based AFBs.
• Co-author:Fan, H ; Zhang, JH; Ravivarma, M ; Li, HB ; Hu, B ; Lei, JF ; Feng, YY; Xiong, SZ ; He, C ; Gong, JY ; Gao, TY ; Song, JX
• Volume:2020,12(39) 43568-43575
• Page Number:2020,12(39) 43568-43575
• Translation or Not:No
• Date of Publication:2020-09-30