Physical and electrochemical performance of Mn-doped zinc oxide electrode material for asymmetric supercapacitor

Abstract

Manganese-doped zinc oxide has emerged as a promising material for high-performance supercapacitors (SCs) due to its enhanced electrochemical properties, including improved charge storage capacity and cycling stability. Pristine Zinc oxide (ZO) and Manganese (Mn) doped (2 wt % and 4 wt %) zinc oxide (hereby labeled: ZO, 2MZO, and 4MZO) derivatives have been synthesized via an aqueous sol-gel-based co-precipitation method. The physical characterizations of synthesized samples have been performed using TGA, XRD, FESEM, and BET. The XRD has confirmed the phase pure hexagonal wurtzite structure synthesis of ZO, 2MZO, and 4MZO samples. The FE-SEM images revealed that synthesized material had shown the mixed morphology as polyhedral particles, rods, and flakes in the nano region. Mn-doped has increased specific surface by 132 % compared to bare ZO. The electrochemical characterization techniques, including CV, GCD, and EIS, have been used to access electrochemical parameters using an aqueous 4 M KOH electrolyte. A detailed CV analysis was also carried out to investigate the capacitive contribution of the material in cycling. The electrochemical characterization techniques (CV, GCD, and EIS) have been performed to access electrochemical parameters using an aqueous 4 M KOH electrolyte. The 4MZO electrode material has shown an enhancement in specific capacitance (164.28 Fg^-1) compared to pristine ZO (42.83 Fg^-1). The EIS study revealed that the 4MZO has the lowest internal impedance 0.30 Ω compared to 0.70 Ω, and 2.60 Ω for 2MZO and ZO, respectively.