1. Spatial structure regulation towards armor-clad five-membered pyrroline nitroxides catholyte for long-life aqueous organic redox flow batteries.
- Author
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Hao Fan, Kai Liu, Xudong Zhang, Yunpeng Di, Pan Liu, Jiaqi Li, Bo Hu, Hongbin Li, Ravivarma, Mahalingam, and Jiangxuan Song
- Subjects
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SUPRAMOLECULAR chemistry , *ENERGY storage , *CYCLODEXTRINS , *DISPROPORTIONATION (Chemistry) , *IONIC conductivity - Abstract
Five-membered pyrroline nitroxides with high-potential is fascinating as catholyte for aqueous organic redox flow batteries (AORFBs), however, it suffers from a primary deficiency of insufficient stability due to ring-opening side reaction. Herein we report a spatial structure regulation strategy by host-guest chemistry, encapsulating 3-carbamoyl-2,2,5,5-tetramethylpyrroline-1-oxyl (CPL) into hydrosoluble cyclodextrins (CDs) with an inclusion structure of N-O· head towards cavity bottom, to boost the solubility and cyclability of pyrroline nitroxides significantly. The armor-clad CPL (CPL⊂HP-β-CD) catholyte in 0.05-0.5 M presents a battery capacity fade rate as low as 0.002 %/cycle (0.233 %/day) compared to the sole CPL in 0.05 M (0.039 %/cycle or 5.23 %/day) over 500 cycles in assembled AORFBs. The optimized reclining spatial structure with N-O· head towards CD cavity bottom effectively inhibits the attack of Lewis base species on the hydrogen abstraction site in pyrroline ring, and thus avoids the ring-opening side reaction of pyrroline nitroxides. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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