Proton‐Resistant <i>N</i> ‐Heterocycle‐Linked TEMPO Catholytes for Long‐Lasting Neutral Aqueous Organic Redox Flow Batteries
Abstract
Abstract TEMPO is a widely studied catholyte for aqueous organic redox flow batteries (AORFBs) but suffers from proton‐induced ring‐opening degradation when its solubility is enhanced via hydrophilic substitution at the 4‐position, leading to structural failure and rapid capacity fade. To address this issue, five TEMPO derivatives were synthesized through N ‐acetylamino bridging and nitrogen‐containing heterocycle grafting strategy. Combined analyses using atomic dipole moment‐corrected Hirshfeld (ADCH) charges, Fukui functions, and linear ion trap mass spectrometry (LTQ‐XL) reveal that aromatic heterocycle functionalization enables favorable charge redistribution during redox cycling, enhancing both redox kinetics and molecular stability. In particular, dimethylaminopyridine‐functionalized TEMPO (DMA‐TEMPO) exhibits enhanced π‐conjugation and basicity, which suppresses proton‐driven ring‐opening and significantly improves structural resilience. 1 M DMA‐TEMPO catholyte delivers exceptional cycling performance, retaining 99.98% of its capacity after 560 cycles, while 2 M system maintains 97% capacity over 100 cycles. Compared to its structural analog 1 M PA‐TEMPO, the cycle life is improved 18‐fold. This study offers a robust molecular design strategy for developing proton‐resistant catholytes, advancing the practical deployment of long‐lasting AORFBs for grid‐scale energy storage.
Article Details
Authors (12)
Yujie Zhao
Department of Chemistry
Xu Liu
Zengrong Wang
Frontier Institute of Science and Technology, Interdisciplinary Research Center of Frontier science and technology, State Key Laboratory for Strength and Vibration of Mechanical Structures, Engineering Research Center of Key Materials For Efficient Utilization of Clean Energy of Shaanxi Province, Xi'an Key Laboratory of Electronic Devices and Material Chemistry Xi'an Jiaotong University Xi'an Shaanxi P. R. China
Jiapeng Huang
Junjie Huang
Xiaotong Deng
Frontier Institute of Science and Technology Interdisciplinary Research Center of Frontier science and technology State Key Laboratory for Strength and Vibration of Mechanical Structures Institute of New Concept Sensors and Molecular Materials Shaanxi Key Laboratory of New Conceptual Sensors and Molecular Materials Engineering Research Center of Key Materials for Efficient Utilization of Clean Energy of Shaanxi Province National innovation Platform (Center) for Industry‐Education Integration of...
Xuri Zhang
Frontier Institute of Science and Technology, Interdisciplinary Research Center of Frontier science and technology, State Key Laboratory for Strength and Vibration of Mechanical Structures, Engineering Research Center of Key Materials For Efficient Utilization of Clean Energy of Shaanxi Province, Xi'an Key Laboratory of Electronic Devices and Material Chemistry Xi'an Jiaotong University Xi'an Shaanxi P. R. China
Heng Zhang
Haiyan Yu
State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Guangdong Provincial Key Laboratory of Applied Marine Biology, Chinese Academy of Sciences
Ya‐Ke Li
MOE Key Laboratory for Non‐Equilibrium Synthesis and Modulation of Condensed Matter School of Physics Xi'an Jiao tong University Xi'an Shaanxi Province 710049 P.R. China
Gao‐Lei Hou
MOE Key Laboratory for Non‐Equilibrium Synthesis and Modulation of Condensed Matter School of Physics Xi'an Jiao tong University Xi'an Shaanxi Province 710049 P.R. China
Gang He