Orthoquinone–Based Covalent Organic Frameworks with Ordered Channel Structures for Ultrahigh Performance Aqueous Zinc–Organic Batteries

Abstract

Elaborate molecular design on cathodes is of great importance for rechargeable aqueous zinc-organic batteries' performance elevation. Herein, we design a novel orthoquinone-based covalent organic framework with an ordered channel structures (BT-PTO COF) cathode for an ultrahigh performance aqueous zinc-organic battery. The ordered channel structure facilitates ions transfer and makes the COF follow a redox pseudocapacitance mechanism. Thus, it delivers a high reversible capacity of 225 mAh g^-1 at 0.1 A g^-1 and an exceptional long-term cyclability (retention rate 98.0 % at 5 A g^-1 (≈18 C) after 10 000 cycles). Moreover, a co-insertion mechanism with Zn²⁺ first followed by two H⁺ is uncovered for the first time. Significantly, this co-insertion behaviour evolves to more H⁺ insertion routes at high current density and gives the COF ultra-fast kinetics thus it achieves unprecedented specific power of 184 kW kg^-1 _(COF) and a high energy density of 92.4 Wh kg^-1 _(COF) . Our work reports a superior organic material for zinc batteries and provides a design idea for future high-performance organic cathodes.