Preparation And Electrochemical Properties Of Cobalt Oxide Particles With Different Morphologies

Supercapacitor as a energy storage device, due to its high capacity, fast charge-discharge characteristics, stable electrical performance and excellent performance, it has become the hot topic capacitive means after the lithium-ion battery. Cobalt oxide as an electrode material for supercapacitors, with storage capacity, cheap, and the high specific capacitance characteristics, has become the hot of the researchers studying. Nano and micron cobalt tetroxide particles are successfully prepared in this paper with different morphology in hydrothermal- thermal decomposition and hydrothermal method, and the capacitance of cobalt oxide with different morphologies in the supercapacitor were tested.The cobalt nitrate and urea dissolved in water,which heated at 160 ℃ with different times(2 h、3 h、4h、5h、12h、24h、48h) prepared the precursor carbonate, cobalt carbonate heated at 500 ℃ in 3 h decompose to the cobalt oxide particles. XRD, SEM and Raman Characterization were employed to test the samples. The results showed that the cubic phase cobalt oxide with high purity were successfully prepared under different pre-processing time. When the pre-processing time was 2 h and 24 h, respectively, cobalt oxide grains were hedgehog spherical and cubic. Finally, the electrochemical performance of cobalt oxide samples with different morphologies were tested, capacitance of hedgehog spherical and cubic cobalt were 40F/g and 24F/g, respectively.On the basis of hydrothermal- thermal decomposition experiment, the rod(pH = 9) and nano disc(pH = 12) cobalt oxide grains were successfully prepared in hydrothermal method by adjusting the pH(9、10、11、12)of the solution. The samples were characterized by XRD and SEM. The results showed that the cobalt oxide are high purity cubic crystal. Electrochemical results show that specific capacitance of nano-rod and the disc-shaped cobalt oxide were 32F/g and 200F/g.