Kimia Zarean Mousaabadi, Ali A. Ensafi, and Behzad Rezaei

ACS Appl. Nano Mater. 2022, 5, 8097−8104, https://pubs.acs.org/doi/abs/10.1021/acsanm.2c01236

ABSTRACT: Recent research studies have focused on energy storage systems such as supercapacitors with high power density, good operational safety, and durable cycling life. Hence, the structure design effectively promotes the excellent performance of pseudocapacitive materials as an electrode in a supercapacitor. In this research, Co3O4/MoCo/LDH is prepared and fabricated as a binder-free electrode on the nickel foam. The Co3O4 nanowires (NWs) and MoCo layered double hydroxides (LDHs) are synthesized via a hydrothermal pathway with a combination of calcination processes and characterized by various techniques, including attenuated total reflectance-infrared (ATR-IR), field emission-scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and X-ray diffraction (XRD) patterns. This electrode enlarges active sites and enhances the rates of ion/electron diffusion. As a result, the Co3O4/MoCo/LDH/NF electrode demonstrates a superb specific capacitance of 2677 F g−1 at 1.0 A g−1 , great cycling stability after 5000 cycles (maintaining 93.2% of its initial capacitance) at 9.0 A g−1 , and an excellent capacity retention rate of 62.86% at 15 A g−1 , which shows better performance than MoCo LDH/NF and Co3O4 NWs/NF electrodes. Furthermore, an asymmetric supercapacitor is fabricated by Co3O4/MoCo/LDH and activated carbon; Co3O4/MoCo/LDH/NF//AC ASC exhibits a specific capacitance of 190.2 F g−1 at 1.0 A g−1 and an outstanding energy density of 67.62 Wh kg−1 at a high power density of 800 W kg−1 . Therefore, it is a promising electrode for energy storage applications.

KEYWORDS: cobalt oxide, molybdenum, energy storage, alkaline media, nanostructures