Porous cobalt oxides/carbon foam hybrid materials for high supercapacitive performance

Porous cobalt oxides/carbon foam hybrid materials (CoO_x/C) was prepared by a solvothermal method. Owing to the heredity of the interconnected hierarchical porous structure from the carbon foam, the obtained CoO_x/C composites had a larger specific surface area and a wider pore size distribution than CoO_x, which facilitated the electron and ion transport. Benefiting from the synergistic contribution of CoO_x nanoparticles and the porous carbon foam, CoO_x/C possessed an excellent supercapacitive performance. When the mass percentage of the carbon foam was 10%, the CoO_x/C composite (CoO_x/C-10) exhibited a high specific capacity (115 mAh g^-1 at 0.5 A g^-1), an excellent rate capability (73 mAh g^-1 at 10 A g^-1) and a good cycling stability (86% after 6000 cycles at 1 A g^-1). Meanwhile, an asymmetric device (CoO_x/C-10//carbon foam) delivered a maximum energy density of 14 Wh kg^-1 at a power density of 9056 W kg^-1 as well as excellent cyclic lifetime (87% after 7000 cycles at 1 A g^-1). In consideration of the excellent supercapacitive performance, the low cost and the facile preparation, CoO_x/C-m is a promising electrode material for the supercapacitors.