Yadav Kushagra, Yadav Rimjhim, Budakoti Praveen K, Bajaj Samiksha, Jain Karishma, Sardar Surajit, Khurana Mehak, Dhakate Sanjay R
Advanced Carbon Products and Metrology Department, CSIR-National Physical Laboratory (CSIR-NPL), New Delhi, 110012, India.
Academy of Scientific and Innovative Research, Ghaziabad, 201002, India.
Chemistry. 2025 Jul 22;31(41):e202501252. doi: 10.1002/chem.202501252. Epub 2025 Jul 7.
Covalent organic frameworks (COFs) with reversible redox-active units are promising materials for electrochemical energy storage devices. The highly extended π-conjugated redox-active PPDA-TFPT-COF is synthesized via Schiff-base condensation between p-phenylenediamine (PPDA) and 2,4,6-tris-(p-formylphenoxy)1,3,5-triazine (TFPT) monomers. The ample redox active sites of PPDA-TFPT-COF enabled exceptional energy storage, achieving a maximum specific capacitance of 250 F g and an energy density of 34.72 Wh kg at a power density of 500 W kg at 1 A g current density. The material demonstrated extraordinary cycling stability, retaining over 100% capacitance after 5000 cycles at 7 A g current density. This superior performance is attributed to π-π interactions, abundant redox-active centers, and an efficient charge transport pathway, making it an ideal supercapacitor electrode material. The presence of diamine moieties enhanced conductivity, while redox-active imine sites facilitated hydrogen ion storage. Electrochemical investigations under acidic conditions revealed significant perturbations in the electronic structure, elucidating the redox charge storage mechanism. Density functional theory (DFT) calculations further confirmed extended π-conjugation in HOMO and LUMO orbitals, providing key insights into charge mobility. This study presents a novel strategy for designing redox-active COFs for high-performance pseudocapacitive energy storage.
具有可逆氧化还原活性单元的共价有机框架（COF）是用于电化学储能装置的有前途的材料。通过对苯二胺（PPDA）与2,4,6 - 三（对甲酰基苯氧基）-1,3,5 - 三嗪（TFPT）单体之间的席夫碱缩合反应，合成了高度扩展的π共轭氧化还原活性PPDA - TFPT - COF。PPDA - TFPT - COF丰富的氧化还原活性位点实现了卓越的能量存储，在1 A g电流密度下，功率密度为500 W kg时，最大比电容达到250 F g，能量密度为34.72 Wh kg。该材料表现出非凡的循环稳定性，在7 A g电流密度下经过5000次循环后，电容保持率超过100%。这种优异的性能归因于π - π相互作用、丰富的氧化还原活性中心和高效的电荷传输途径，使其成为理想的超级电容器电极材料。二胺基团的存在提高了导电性，并促进了氢离子存储，而氧化还原活性亚胺位点则促进了氢离子存储。在酸性条件下的电化学研究揭示了电子结构中的显著扰动，阐明了氧化还原电荷存储机制。密度泛函理论（DFT）计算进一步证实了HOMO和LUMO轨道中的扩展π共轭，为电荷迁移提供了关键见解。本研究提出了一种设计用于高性能赝电容储能的氧化还原活性COF的新策略。
