CuO/Co3O4 materials grown directly on nickel foam for high-performance supercapacitor electrode

Abstract

Electrochemical deposition and successive ionic layer adsorption and reaction (SILAR) are two widely used techniques for preparing semiconductor materials. However, there is limited research on combining the two methods to prepare CuO and Co3O4 composites for supercapacitor applications. In this study, CuO/Co3O4 semiconductor composites with spherical (S–CuO/Co3O4) and wheat spike (W–CuO/Co3O4) morphologies were prepared on nickel foam substrate using a combination of electrochemical deposition and successive ion-layer adsorption. The composites were characterized using X-ray diffraction, X-ray photoelectron spectroscopy, and field emission scanning electron microscopy to confirm their composition and morphology. The electrochemical properties of CuO/Co3O4 materials were investigated using CV, GCD, and EIS. The results show that the load cycle has a significant impact on the performance of CuO/Co3O4, with a load period of 10 cycles exhibiting the best electrochemical performance. A comparison also reveals that the performance of the W–CuO/Co3O4 electrode is better than that of the S–CuO/Co3O4 electrode. In particular, at 1 mA/cm2 current density, the specific capacity of the W–CuO/Co3O4-10 electrode is 86.0 mAh/g, which is larger compared to S–CuO/Co3O4-10 electrode (55.8 mAh/g). After 5000 cycles of galvanostatic charge/discharge, the capacitance retention rate of the W–CuO/Co3O4-10 electrode remains 76.9 %. In addition, two water-system symmetrical supercapacitors connected in series can light up the LED for 8 min and still maintain a certain brightness. Modifying the morphology of composites has a significant impact on improving the capacitive properties of composites. This study demonstrates that the prepared CuO/Co3O4 composite material has good application potential as electrode material for supercapacitors.