Gel-Derived 𝜷-Ketoenamine-Linked Tetraisopropylbenzidine-Based Covalent Organic Polymer for High-Performance Symmetric and Asymmetric Supercapacitors

Abstract

Herein, we report the design and synthesis of a novel redox-active β-ketoenamine-linked covalent organic polymer, TBZTFPG-COP, via Schiff-base polycondensation of 2,2′,6,6′-tetraisopropylbenzidine (TBZ) and 2,4,6-triformylphloroglucinol (TFPG). The incorporation of a sterically hindered and π-rich redox-active monomer (TBZ), imparts enhanced redox reversibility, improved electronic conductivity, and structural disorder that facilitates ion and electron transport. The chemically robust β-ketoenamine linkage contributes to the polymer's hydrolytic and oxidative stability under aqueous conditions. A scalable, energy-efficient synthesis was achieved via a solvothermal gel-phase route, followed by ambient drying and grinding. Electrochemical characterization revealed that TBZTFPG-COP exhibits a synergistic charge storage mechanism, combining pseudocapacitive and electric double-layer behavior. In a three-electrode configuration, the polymer achieved a specific capacitance of 824 F g-1 at 8 A g-1, with an energy density of 114.4 Wh kg-1 and a power density of 10,000 W kg-1. In a symmetric two-electrode device, it delivered 111.4 F g-1 at 1 A g-1, with 15.4 Wh kg-1 and 2500 W kg-1, and 97% capacitance retention after 10,000 cycles. These outcomes unveil TBZTFPG-COP as a versatile and promising material for high-performance symmetric and asymmetric supercapacitors in sustainable energy storage.