Facile Synthesis and Supercapacitor Performance of M3O4(M=FeCoCrMnMg) High-entropy Oxide Powders

Abstract

High-entropy oxides have attracted more and more attention due to their unique structures and potential applications. In this work, M3O4(M=FeCoCrMnMg) high entropy oxide powders were synthesized by a facile solid-state reaction method. The powders were characterized by different methods. Furthermore, M3O4/Ni foam (M3O4/NF) electrode was prepared by a coating method, followed by investigation of its supercapacitor performance. The results showed that, with the increase of calcining temperature, Fe2O3(H)/Co3O4(S)/Cr2O3(E) and Mn2O3(B) dissolved successively in the crystal lattice of spinel structure. After M3O4 powders being calcined at 900℃ for 2 h, single spinel structure (FCC, Fd-3m, a=0.8376 nm) was obtained with uniform distribution of Fe, Co, Cr, Mn, and Mg elements, the typical characteristic of high entropy oxide. In addition, the mass specific capacitance of M3O4/NF composite electrode is 193.7 F•g-1, with 1 mol/L KOH as electrolyte and 1 A•g-1 as current density, which indicated that the M3O4 high entropy oxide can be considered as a promising candidate for the electrode material in the field of supercapacitor applications.