Zn1−xCoxMn1−xFexCrO4 ferrichromate: an efficient material for high performance supercapacitor applications

Abstract

Zn_1−xCo_xMn_1−xFe_xCrO₄ ferrichromate was synthesized using the sol–gel auto-combustion method. Rietveld refinement confirms a single phase simple cubic spinel structure in all the samples. FESEM images indicated mixed morphology for all the samples with nearly hexagonal/spherical shape and the agglomeration of particles. The elemental composition was confirmed using EDAX analysis. To validate the morphology of Zn_1−xCo_xMn_1−xFe_xCrO₄ ferrichromate obtained through FESEM, TEM images were taken, and the TEM images were in accordance with the FESEM images. Different oxidation states of Zn_1−xCo_xMn_1−xFe_xCrO₄ (X = 1.0) ferrichromate was determined using XPS. The surface area of Zn_1−xCo_xMn_1−xFe_xCrO₄ ferrichromate was determined using BET analyzer. Further, the electrical conductivity of all the samples were investigated, and the correlation between the surface area and conductivity were discussed. The as-synthesized Zn_1−xCo_xMn_1−xFe_xCrO₄ ferrichromate materials were tested for their electrochemical and supercapacitor applications. The electrochemical measurements revealed that Zn_1−xCo_xMn_1−xFe_xCrO₄ with concentration (X = 1.00) exhibits superior electrochemical performance over the other samples. A high specific capacitance of 286.94 F g⁻¹ and high energy density of 14.30 W h kg⁻¹ at a scan rate of 10 mV s⁻¹ and 93.4% capacity retention over 5000 cycles were observed for Zn_1−xCo_xMn_1−xFe_xCrO₄ (X = 1.00) ferrichromate. These properties make Co_1.0Fe_1.0Cr_1.0O₄ ferrichromate an excellent electrode material to study supercapacitor applications.