Synthesis and electrochemical properties of polymer solution prepared MnCo2O4 nanoparticles

Abstract

In this work, spinel MnCo2O4 nanoparticles with a particle size of about 40–160 nm were prepared by a simple polymer solution method. The resulting precursor was calcined at 500 °C, 600 °C, 700 °C, and 800 °C to obtain a spinel MnCo2O4 phase. The results of X-ray diffraction and transmission electron microscopy with selected electron diffraction analysis indicated that the MnCo2O4 nanoparticles have a cubic structure. The X-ray absorption near edge structure and X-ray photoelectron spectroscopy spectra have confirmed the mixed valence state of Mn3+/Mn4+ and Co2+/Co3+ in all samples. The electrochemical properties were investigated by using a three-electrode cell system in 6.0 M KOH electrolyte. The sample calcined at 600 °C exhibits the highest specific capacitance value of 282 F/g and 208 F/g at a scan rate of 2 mV/s and at a current density of 1.0 A/g, respectively, and the best capacitance retention with long-term cycling stability over 70% after 1000 cycles. Clearly, calcination temperatures affect to the specific surface area and pore diameter, which can improve the electrochemical performance of the MnCo2O4 nanoparticles.