Triethanolamine–ethoxylate (TEA-EO) assisted hydrothermal synthesis of hierarchical β-MnO2nanorods: Effect of surface morphology on capacitive performance

Here in present paper, we are reporting a facile tri-ethanolamine-ethoxylate assisted hydrothermal synthesis of MnO2 nanorods. Structural (X-ray diffraction, Rietveld refinement), functional (Fourier Transform Infrared spectroscopy and X-ray Photoelectron Spectroscopy) and morphological (Field emission scanning electron microscope, Transmission electron microscopy) characterization conform the β-MnO2 nanostructure with a rod-like morphology and uniform thickness. The morphological variations of the nanorod thickness can be easily controlled by simply monitoring the reaction temperature. Comparative investigations of β-MnO2 samples synthesized at two different reaction temperatures (viz. 100°C and 120 °C) as a supercapacitive electrode material have been performed with the aid of different electrochemical techniques, such as cyclic voltammetry, galvanostatic charge discharge and impedance spectroscopy in different electrolytes (Li2SO4 and Na2SO4). Interestingly, the low temperature synthesized β-MnO2 nanorods sample exhibit superior electrochemical performance in 1 mol L-1 Li2SO4 electrolyte in terms of high specific capacitance (462 Fg-1 at10 mVs-1), energy density (9.72 WhKg-1), and outstanding cyclic stability (90.26 % over 2000 cycles).