Investigations on structural and electrochemical energy storage properties of pH dependent MnWO4 nanoparticles

Abstract The electrochemical characteristics of MnWO4 nanoparticles were engineered via tailoring the pH of the precursor solution during the facile co-precipitation synthesis. The MnWO4 electrodes were examined for their physicochemical properties using various characterization techniques, wherein the structural study confirms the pure monoclinic crystal structure having a P2/c space group. The electrochemical study confirms the presence of distinct redox peaks during the voltammetry measurements, suggesting efficient intercalation processes. The charge-storage kinetics study confirms that a more complex process than pure diffusion control is involved in electrochemical measurements. The MnWO4 electrode synthesized at pH 11 exhibited a specific capacitance of 711 F g−1 at a scan rate of 10 mV s–1, along with a capacitance retention of 90.3% at a scan rate of 100 mV s– 1. Moreover, the MnWO4//AC asymmetric device exhibited a remarkable electrochemical performance, achieving a high energy density of 24.30 Wh kg−1 at a power density of 950 W kg−1. This study reveals the significant role of pH during the synthesis of nanomaterials, which governs the phase formation, morphological modifications, and electrochemical performance. These results suggest that MnWO4 is an ideal candidate for advanced energy-storing devices.