Dual Molecules Cooperatively Confined In-Between Edge-oxygen-rich Graphene Sheets as Ultrahigh Rate and Stable Electrodes for Supercapacitors

Noncovalent modification of carbon materials with redox-active organic molecules has been considered as an effective strategy to improve the electrochemical performance of supercapacitors. However, their low loading mass, slow electron transfer rate, and easy dissolution into the electrolyte greatly limit further practical applications. Herein, this work reports dual molecules (1,5-dihydroxyanthraquinone (DHAQ) and 2,6-diamino anthraquinone (DAQ)) cooperatively confined in-between edge-oxygen-rich graphene sheets as high-performance electrodes for supercapacitors. Cooperative electrostatic-interaction on the edge-oxygen sites and pi-pi interaction in-between graphene sheets lead to the increased loading mass and structural stability of dual molecules. Moreover, the electron tunneling paths constructed between edge-oxygen groups and dual molecules can effectively boost the electron transfer rate and redox reaction kinetics, especially at ultrahigh current densities. As a result, the as-obtained electrode exhibits a high capacitance of 507 F g(-1) at 0.5 A g(-1), and an unprecedented rate capability (203 F g(-1) at 200 A g(-1)). Moreover, the assembled symmetrical supercapacitor achieves a high energy density of 17.1 Wh kg(-1) and an ultrahigh power density of 140 kW kg(-1), as well as remarkable stability with a retention of 86% after 50 000 cycles. This work may open a new avenue for the efficient utilization of organic materials in energy storage and conversion.

Automated summary

This study presents a dual molecule (1,5-dihydroxyanthraquinone (DHAQ) and 2,6-diamino anthraquinone (DAQ)) confined between edge-oxygen-rich graphene sheets as high-performance electrodes for supercapacitors. The cooperative electrostatic interaction and pi-pi interaction lead to increased loading mass and structural stability of dual molecules. The constructed electron tunneling paths between edge-oxygen groups and dual molecules effectively enhance electron transfer rate and redox reaction kinetics. The obtained electrode exhibits high capacitance, unprecedented rate capability, and remarkable stability, making it promising for efficient utilization of organic materials in energy storage and conversion.