Ion-by-Ion Adsorption Process and Reaction for the Synthesis of Hierarchical Manganese Tungstate (MnWO₄) Microflowers as an Energy-Efficient Electrode for Supercapacitors

Abstract

For the first time, manganese tungstate (MnWO 4 ) electrodes are successfully synthesized by the successive ionic layer adsorption and reaction (SILAR) method. This study is mainly focused on synthesized hierarchical MnWO 4 microflowers (MFs) for electrochemical supercapacitor application. The crystalline structure, morphology, presence of functional groups, stretching and bending vibration, and availability of chemical states present in the MnWO 4 MFs are investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared, Raman, and X-ray photoelectron spectroscopy, respectively. In addition, the resultant materials undergo electrochemical analysis using a three-electrode system. As a result, the MnW-50 electrode reveals a maximum specific capacitance (Cs) and capacity (Csp) of 698 F/g and 87 mAh/g at 5 mA/cm 2 with moderate energy density (ED) and power density (PD) of 19 Wh/kg and 700 W/kg, respectively. Furthermore, the aqueous hybrid device is fabricated using MnWO 4 MFs as a cathode and reduced graphene oxide (rGO) as an anode material, which reveals the maximum performance of the Cs and Csp of 206 F/g and 87 mAh/g at 5 mV/s and 185 F/g and 70 mAh/g with sufficient ED, and PD of 45 Wh/kg and 1960 W/kg at 5 mA/cm 2 , respectively. The aforementioned results indicate the benefits and improved electrochemical efficiency of MnWO 4 MFs as cathodes for hybrid supercapacitors.