Facile fabrication 1D/2D/3D Co_3O_4 nanostructure in hydrothermal synthesis for enhanced supercapacitor performance

摘要

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.