Construction of hierarchical MnMoO4 nanostructures on Ni foam for high-performance asymmetric supercapacitors

Abstract

Metal molybdates have gained a notable curiosity in the field of supercapacitors because of their magnificent electrochemical properties. The MnMoO4 nanostructures were prepared on nickel foam (NF@MnMoO4) by an in situ hydrothermal method by swapping the pH values of the precursor solution, maintaining other reaction parameters such as hydrothermal temperature and time as constant. The secured nanostructures were characterized by X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. Electrochemical studies accomplished on a three-electrode cell having NF@MnMoO4 as the working electrode manifested a high specific capacitance of 428.7 mF cm−2, at a current density of 2 mA cm−2. The hybrid asymmetric supercapacitor constructed using NF@MnMoO4 as a positive electrode and in situ hydrothermally prepared reduced graphene oxide (r-GO) deposited on the NF as a negative electrode presented a maximum energy density of 0.41 mW h cm−3 at a power density of 40.9 mW cm−3.