Electrochemical investigation of manganese ferrites prepared via a facile synthesis route for supercapacitor applications

We report on a simple and facile synthesis of manganese ferrite (MnFe2O4) nanoparticles by chemical co-precipitation method using 1 M NaOH as the oxidative solution. The resultant nanoparticles were characterized by using various tools like powder X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. The morphology of the resultant product was observed to be of spherical in shape with diameter of about 20-50 nm. The electrochemical performance of manganese ferrite nanoparticles was investigated by using cyclic voltammetry, charge-discharge and electrochemical impedance spectroscopy with different electrolytes, such as 1 M LiNO3, 1 M Li3PO4 and KOH. In a three-electrode system, a maximum specific capacitance of 173, 31 and 430 F g(-1) was attained corresponding to the electrolytes of 3.5 M KOH, 1 M LiNO3 and 1 M Li3PO4, respectively. Among these, 3.5 M KOH electrolyte medium exhibited excellent rate performance, evidently more than 60% of retention was observed at 10 A g(-1) due to the synergistic activities, high surface accessibility and better electronic conductivity of MnFe2O4 nanoparticles. In addition, the fabrication of symmetric cell using MnFe2O4 as an electrode materials with 3.5 M KOH as an electrolyte, exhibited maximum specific capacitance, high energy density and power density of 245 F g(-1), 12.6 Wh kg(-1) and 1207 W kg(-1), respectively. Furthermore, the specific capacitance of 105% retained after 10,000 cycles at the high current density of 1.5 A g(-1) and the coulombic efficiency of the all 10,000 cycles remains constant (similar to 98) which clearly displayed the excellent electrochemical stability of MnFe2O4 nanosphere (NS). Our results may pave the way for employing the low-cost co-precipitation method to fabricate advanced high energy storage and highly stable device with long cycle life.