Morphology tuning of porous CoO nanowall towards enhanced electrochemical performance as supercapacitors electrodes

CoO with porous nanowall structure is fabricated by a combined solvothermal and annealing process. The micromorphology of CoO is fine-tuned by controlling the annealing temperature. Nano-sized pores below ∼50 nm are achieved at 400 °C annealing with a high specific surface area of 65 m2 g−1. The unique porous nanowall structure leads to large surface areas and increase electrolyte/electrode interfaces, benefiting enhanced electrochemical performance of CoO. High specific capacitance of 352 F g−1 has been obtained at 1 A g−1 with good rate capability (72.7% capacitance retention from 1 to 20 A g−1) and good cycling stability (92.9% of initial capacitance after 5000 cycles), making it a promising electrode for supercapacitor.