Synthesis and characterization of Cd-doped ZnMn2O4 microspheres as supercapacitor electrodes

In this paper, we demonstrate the effects of Cd-doping ZnMn2O4 on structural and electrochemical performance. Cd-doped ZnMn2O4 spheres with diameters of about 2 mu m were successfully synthesized by a facile hydrothermal method at 200 degrees C for 18 h. The fabricated Cd-doped ZnMn2O4 samples were characterized by X-ray diffraction, scanning electron microscopy, Brunauer Emmett Teller surface area analyzer and X-ray photoelectron spectroscopy. The electrochemical performance was investigated by cyclic voltammetry and electrochemical impedance spectrometry. The experimental results show that the synthesized spherical Cd-doped ZnMn2O4 exhibit far better rate capability and cyclic stability than that of pure spinel porous ZnMn2O4 microspheres. The result of cyclic voltammetry measurement indicates that the obtained Cd-doped ZnMn2O4 microspheres exhibited the high specific capacitance of 364 Fg(-1) at 2 mV/s.