Porous Co₃O₄ nanowires derived from long Co(CO ₃)_0.5(OH)·0.11H₂O nanowires with improved supercapacitive properties

Porous Co₃O₄ nanowires with large aspect ratio have been obtained by annealing long Co(CO₃)_0.5(OH)·0. 11H₂O precursor nanowires synthesized by a facile hydrothermal method. The results show that the amount of the additive (urea) has an important impact on the morphology of the as-synthesized cobalt-carbonate-hydroxide intermediate, where the uniformity and the overall structure can be controlled by changing the urea concentration. After the heat treatment, the as-obtained phase-pure Co₃O₄ nanowires with a well retained structure are applied as the electrode material for supercapacitors, and the sample exhibits excellent performance with a high specific capacitance of 240 F g ^-1 after 2000 charge/discharge cycles, corresponding to a retention of 98% of the initial capacitance.