Orthoquinone-Based Covalent Organic Frameworks with Ordered Channel Structures for Ultrahigh Performance Aqueous
Shibing Zheng1, Dongjie Shi1, Dong Yan1
1Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Renewable Energy Conversion and Storage Center, College of Chemistry, Nankai University, Tianjin, 300071, China.
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.
