Heterointerfacial Charge Modulation of p-Type Covalent Organic Frameworks on Graphene Achieving High-Performance Cl⁻ Ion Storage with Ultralong Cycling Life

The charge and ion transport dynamics, storage capacity, and cycling performance of Faradaic Cl⁻ ion storage electrodes have recently constrained advancements in supercapacitor (SC) and capacitive deionization (CDI). Herein, a high-performance p-type COF (TAPA-COF)-based Cl⁻ ion storage material (TAPArGO) with exceptional cycling stability was synthesized via an in situ condensation reaction utilizing graphene as a conductive substrate. The interfacial coupling involving graphene and TAPA-COF increases the interfacial electron density, boosting local charge accumulation and Cl⁻ ion storage capacity. Additionally, the dual conductive strategy of incorporating graphene and extended π-electron delocalization of TAPA-COF enhances the redox kinetics, while the triphenylamine N redox centers and flexible graphene network improve cycling stability. Consequently, the Cl⁻ ion asymmetric SC employing the TAPArGO-75 positive electrode achieves a specific energy output of 52.4 Wh kg⁻¹ at 950 W kg⁻¹, with exciting cycling durability retaining 96.8% of the initial capacity after 100 000 cycles. Furthermore, the hybrid CDI system based on the TAPArGO-75 positive electrode demonstrates a specific adsorption capacity of 55.0 mg g⁻¹, along with remarkable cycling desalination/regeneration ability (99.8% after 200 desalination/regeneration cycles). This study expands the application potential of COF-based materials for high-performance Cl⁻ ion storage.