Anthraquinone-modified nitrogen-doped graphene aerogel for boosting energy density of supercapacitors by self-matching of capacity

When an electrode (negative/positive) with excellent capacity matches a counter electrode with relatively low capacity or a pair of excellent electrodes cannot match each other, overall performance of the constructed supercapacitors (SCs) will be limited. Here, we report a novel electrode material 1,5-diamino-4,8-dihydroxyanthraquinone (DHAQ) grafted nitrogen-doped graphene aerogel (DHAQ-NGA) prepared by simple hydrothermal method. Since DHAQ molecule contains -C(=O)- and -NH-/-OH groups, the DHAQ-NGA composite can act as both the negative and positive electrode materials for a supercapacitor in ionic liquid electrolyte to improve capacity by faradaic reactions on these two electrodes. In addition, the intramolecular hydrogen bonding of DHAQ can improve the stability of the material. Therefore, DHAQ-NGA displays an enhanced specific capacity of 410 C g(-1) for the positive electrode and 454 C g(-1) for the negative electrode material. The assembled device can deliver a high energy density of 117 Wh kg(-1) at a power density of 822 W kg(-1). (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The novel electrode material DHAQ-NGA serves as both the negative and positive electrode materials in an ionic liquid electrolyte, improving capacity through faradaic reactions and stability through intramolecular hydrogen bonding, resulting in an enhanced specific capacity.