Multi-sized nanosheets cobalt-iron layered double hydroxide grown on nickel foam as high performance supercapacitor electrode material

Abstract To improve the electrochemical performance and overcome the disadvantages of layered double hydroxides (LDHs), designing the three-dimensional structure may be an effective way. Based on this strategy, we successfully synthesized multi-sized nanosheets cobalt-iron layered double hydroxides (Co-Fe LDHs) on Ni foam by a facile hydrothermal reaction. The poor conductivity of LDHs can be improved by directly grown on Ni foam which can be used as conductive skeleton. The sample has a unique three-dimensional structure with multi-sized nanosheets observed from scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. The elements and structure are confirmed by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The electrodes show a great specific capacitance of 3340 mF cm−2 (1670 C cm−2) at 1 mA cm−2 and good cycling stability which keeps the capacitance retention at 85.1% after 4000 cycles. The improved performances may be due to the unique structure with multi-sized nanosheets and the Ni foam used as conductive skeleton to reduce agglomeration and strengthen conductivity. The results indicate the Co-Fe LDHs grown on Ni Foam have a promising future as supercapacitor electrodes.