Graphene quantum dots/Ni(OH)2 nanocomposites on carbon cloth as a binder-free electrode for supercapacitors

Abstract

Graphene quantum dots (GQDs)/Ni(OH)2 composites on carbon cloth (G-NH//CC) are prepared through simple hydrothermal reactions. The resulting G-NH//CC is employed as a binder-free electrode of supercapacitors. Due to the enhanced electrical conductivity and efficient ion transport by the addition of GQDs, the G-NH//CC electrode exhibits enhanced electrochemical performances. Specifically, the G-NH//CC delivers a maximum specific capacitance of 1825 F g−1 at a current density of 1 A g−1 as well as a good cycle stability of 83.5 % capacity retention after 8000 cycles. Additionally, all-solid-state symmetric supercapacitor (SSC) is assembled with G-NH//CC composites as both positive and negative electrodes. The fabricated SSC exhibits a high energy density of 80.8 Wh kg−1 at a power density of 2021 W kg−1. The present study provides a facile and efficient strategy to prepare high-performance electrode materials for advanced electrochemical energy storage devices.