Coupling of chrysanthemum-shaped cobalt hydroxide and nitrogen-doped carbon dots for high-performance hybrid supercapacitors

Cobalt hydroxide is expecting electrode material for high-performance supercapacitors, however, it is still a challenge to improve its lack of transmission track and active sites. An effective method to improve the elec-trochemistry performance of cobalt hydroxide is to couple it with graphene quantum dots. Herein, we report the preparation of Cobalt hydroxide/N doped graphene quantum dots (Co(OH)2/NQDs) composites and study the electrochemistry performance of Co(OH)2/NQDs composites as supercapacitors electrode materials. Benefit from the strong coupling between NQDs and Co(OH)2 creates new electron transfer channels (Co-N). The hybrid supercapacitor device based on Co(OH)2/NQDs composite and GA shows a high energy density of about 33.6 Wh kg-1 at a power density of 800 Wk g-1, and it retains about 137% specific capacitances after 8000 cycle test. Due to the negative potential of NQDS, it can generate an electrostatic reaction with Co2+, which can stabilize cobalt hydroxide after long cycles.