Tailoring the Structural and Electrochemical Properties of Dual-Phase Sr–Cu Oxides via Mn Doping for a High-Performance Asymmetric Supercapacitor Device
摘要
The fabrication of carbon-free, environmentally friendly, and cost-effective electrode materials exhibiting excellent energy density, power density, and stability is at the core of the supercapacitor field of research. In this study, we have synthesized strontium–copper oxide (SCO) material by the hydrothermal process and reported the effect of various Mn doping concentrations (3 wt.%, 6 wt.%, and 9 wt.%) on the structural and electrochemical behavior of the synthesized material. The x-ray diffraction (XRD) analysis revealed the formation of two types of orthorhombic phases. Rietveld refinement of the XRD spectra indicated that doping with Mn decreases the cell parameters and changes the ratios of the phases. Raman and Fourier transform infrared (FTIR) spectroscopy confirmed the formation of chemical bonding of SCO, and scanning electron microscopy (SEM) analysis showed a decrease in the grain size of the material with an increase in Mn doping. The electrochemical analysis revealed a remarkable enhancement in the specific capacitance with increasing Mn doping from 107 F/g to 512 F/g and an increase in the diffusion coefficient to 4.49 × 10−9 cm2 s−1 for the SCO sample with 9 wt.% Mn doping (SCMO9). Furthermore, the SCMO9//AC supercapacitor device operating with 6 M KOH solution shows exceptional values of energy density (45.01 Wh kg−1) and power density (4379 W kg−1). The device exhibits excellent cyclic performance, retaining 92.5% of the capacity with current density of 6 A/g after 3000 cycles.