Triazine-containing Covalent Organic Polymer-derived Grid-Like Multilocular Spheres for Aqueous Supercapacitors

Abstract

Triazine-containing covalent organic polymers (TCOPs) with unique structures and physicochemical properties are of great potential in energy storage and conversion applications, yet how to finely tune the morphology, and the accessible active sites, and to enhance capacitive activity remains a challenge. Here, the grid-like multilocular spheres derived from TCOP with abundant redox active sites and unique structures are fabricated via a molecular twist-induced regulation strategy, of which the number and size of cavities can be finely modulated by changing the conformers of the twisted unit and the Ostwald ripening time. The unique structure of the as-fabricated TCOP results in unprecedented high specific capacitance (8412 F g⁻¹ at 1 A g⁻¹) and enables the as-assembled supercapacitor with an ultra-high energy density of 675 Wh kg⁻¹ in redox-active electrolyte (KI-mixed H₂SO₄), much better than all reported aqueous supercapacitors thus far. It is found that the high electro-activity is due to the synergistic effect of the enhanced accessibility of active sites and the enhanced interaction of the abundant active sites with the redox-active electrolytes. This approach may pave a new way to precise synthesis of COPs with tuned structure and properties for application-inspired cutting-edge electrochemical energy storage and beyond.