Graphene-supported ultra-small Co3O4 nanoparticles for high-performance supercapacitors

Ultra-small Co3O4 nanoparticles/graphene hybrid material had been synthesized by a facile hydrothermal route and consequent calcination process. The as-obtained ultra-small Co3O4 nanoparticles with their sizes of 5–8 nm are tightly anchored on the surface of graphene (GNS). Benefiting from the ultra-small size of Co3O4 nanoparticles, the high interconnectivity of hybrid material as well as the high conductive networks constructed by GNS, which can provide a fast and efficient transportation of electron and electrolyte ions for the overall electrode, the as-prepared hybrid material exhibits a high specific capacitance of 462 F•g1 at 5 mV•s1 compared with pure Co3O4 (193 F•g1), and retained 88.2% of its initial capacitance after 2000 cycles, indicating a promising electrode material for supercapacitors.