Facile fabrication 1D/2D/3D Co3O4 nanostructure in hydrothermal synthesis for enhanced supercapacitor performance

Adjusting the microstructure is an available strategy to obtain high-performance electrode materials. Herein, we propose a promising and simple hydrothermal method to prepare Co3O4 with improved electrochemical performance by adjusting its microstructure. Co3O4 with different morphologies in the form of band-like, chrysanthemum-like and feather-like can be easily obtained by adjusting the amount of urea in solutions. After analysis, the band-like and feather-like Co3O4 are dominated by surface-control during the oxidation reaction process, while chrysanthemum-like Co3O4 is dominated by diffusion-control during the oxidation reaction process. The experimental results show that the chrysanthemum-like structure of Co3O4 composed of nanowires can be obtained when urea addition is 7 mmol, and it exhibits exciting specific capacity (122.3 mAh g(-1) at 1 A/g) and higher rate capability (70% at 20 A/g). Surprisingly, the specific capacity is still 100% of the initial value after 3000 cycles. The asymmetric supercapacitor assembled with activated carbon as anode and Co3O4 as cathode outputs high specific energy (35.3 Wh/kg at 788.8 W/Kg), good cycle stability (capacity retention rate of 82.6% after 10,000 cycles) and excellent coulombic efficiency. These results fully demonstrate that Co3O4 prepared in this work has great potential as an energy storage electrode material.

Automated summary

Adjusting the microstructure of Co3O4 using a hydrothermal method can greatly improve its electrochemical performance. The chrysanthemum-like structure of Co3O4, obtained by adding 7 mmol of urea, shows the best specific capacity and rate capability among different morphologies.