Herein, we demonstrate an advanced cathode of nitrogen-doped carbon dots (NCDs) anchored NiO/Co3O4 ultrathin nanosheets for hybrid supercapacitors by a facile hydrothermal-calcination route. Owing to the well defined thin-plate structure and ternary composition, the optimized NiO/Co3O4/NCDs nanosheets demonstrate a high specific capacity of 976.3 C g(-1) (1775 F g(-1)) at 1 A g(-1), and a splendid cycling stability of approximately 95.7% retention over 10,000 continuous cycles (15 A g(-1)). In addition, a hybrid supercapacitor is constructed by using NiO/Co3O4 /NCDs nanosheets as cathode and reduced graphene oxide (RGO) supported NCDs composites as anode. The obtained NiO/Co3O4/NCDs//RGO/NCDs hybrid supercapacitor delivers a maximum energy density of 41.6 Wh kg(-1), together with outstanding cycling stability (no decay after 10,000 cycles at 10 A g(-1)). Therefore, the ultrathin sheet-like structured NiO/Co3O4/NCDs cathode presents a great potential for supercapacitor application. (C) 2020 Elsevier Inc. All rights reserved.