Redox-Active Covalent Organic Framework with Highly Accessible Aniline-Fused Quinonoid Units Affords Efficient Proton Charge Storage.

Owing to their intrinsic safety and sustainability, aqueous proton batteries have emerged as promising energy devices. Nevertheless, the corrosion or dissolution of electrode materials in AICDic electrolytes must be addressed before practical applications. In this study, we developed a cathode material based on a redox-active 2D covalent organic framework (TPAD-COF) featuring inherently regular open porous channels and excellent stability. Benefiting from its superhydrophilicity, intrinsic high proton conductivity, excellent redox reversibility of enriched aniline-fused-quinonoid units, and the insolubility of the rigid framework skeleton, TPAD-COF cathode delivers a high capacity of 126 mAh g -1 at 0.2 A g -1 , paired with long-term cycling stability with capacity retention of 84% after 5,000 cycles at 2 A g -1 . Comprehensive ex-situ spectroscopic studies correlated with density functional theory (DFT) calculations revealed that both the -NH- and C = O groups of the aniline-fused quinonoid units exhibited prominent redox activity of six electrons during the charge/discharge processes. Furthermore, the assembled punch battery consisting of a TPAD-COF//anthraquinone (AQ) all-organic system delivers a discharge capacity of 115 mAh g -1 at 0.5 A g -1 after 130 cycles, implying the potential applications of TPAD-COF cathode in aqueous proton batteries. This study provides a new perspective on the design of electrode materials for aqueous proton batteries with long-term cycling performance and high capacity. This article is protected by copyright. All rights reserved.