This paper discusses the effect of pulse current under frequency and duty cycle variations on the morphology and crystal structure of electrolytic manganese dioxide (EMD) deposits. The pulse current electrolysis method is proposed to improve EMD morphology, which is indicated by finer particle size, and crystallinity. The electrolysis experiments by constant current and pulse current methods have been carried out, and the morphology and crystal structure of the synthesized EMD were compared. For both methods, the electrodes used were titanium for the anode and carbon for the cathode. The electrolyte consists of 90 g/L MnSO4 and H2SO4 0.5 M. The deposits of EMD were analyzed using SEM and XRD to observe their morphology and crystal structure. The results of the direct current electrolysis experiment showed that a higher current density leads to a reduction of current efficiency and produces finer particle size. Higher temperatures than 90 °C resulted in lowering current efficiency and larger grain size of EMD. For pulse current electrolysis, the results showed that higher frequency and duty cycle reduce grain size. The finest grain size of EMD was obtained at the experiment with a 75% duty cycle and frequency of 185 Hz. The EMD produced by direct and pulse currents were γ-MnO2 and ε-MnO2, respectively. The EMD produced by the pulse current electrolysis has a better crystallinity.

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