Mesoporous 3D graphene@NiCo2O4 arrays on nickel foam as electrodes for high-performance supercapacitors

• A 3D graphene@NiCo2O4 hierarchitecture have been decorated on nickel foam.
• The electrode exhibits a high specific capacitance of 1688 F g−1 at 15 A g−1.
• The electrode shows good capacity retention of 123% even after 1500 cycles.

A 3D graphene@NiCo2O4 hierarchitecture was prepared through by chemical vapor deposition and electrochemical deposition. The nickel foam was first coated with a thin graphene layer and then decorated with NiCo2O4 nanosheets, which consisted of many nanoparticles, approximately 4 nm. The specific capacitance of the obtained electrode was as high as 1688 F g−1 at a very high current density of 15 A g−1, exceptional rate capability (71.5% capacity retention from 2 to 15 A g−1) and good cycling stability (123% of the initial capacity for 1500 cycles), highlighting its promising applications as a high performance electrode for supercapacitors.