▎ 摘　　要

The core shell structure of Cobalt@carbon nano rod/reduced graphene oxide (Co@CNR/rGO) is facilely synthesized with a one-pot hydrothermal process. Nitrogen is also introduced into the carbonaceous materials during the synthesis process. Calcination is added to graphitize the carbonaceous material, and simultaneously crystallize the Co particles. To assemble an electrode, the calcined Co@N-CNR/rGO material is uniformly loaded onto a collector of nickel foam by electrophoretic deposition. The specific capacitance is measured to be as high as 3233.3 F g(-1) at a current density of 0.1 A g(-1). Three-dimensional rGO aerogels with desirable rate ability and cyclic stability are self-assembled with a hydrothermal reduction process from graphene oxide. Practically, the calcined Co@N-CNR/rGO and 3D rGO aerogel are utilized as cathode and anode to fabricate an asymmetric supercapacitor device, respectively. The operating voltage window of the device is increased to 1.5 V, and the energy density reached 31.8 Whkg(-1) at a power density of 302 W kg(-1), and 11.2 Whkg(-1) at 45,000 W kg(-1), respectively. The cyclic galvanostatic charge discharge stability is also measured and showed 99.2% capacity retention after 10,000 cycles at a current density of 5 A g(-1). (c) 2020 Elsevier Ltd. All rights reserved.