Spinel-Type (FeCoCrMnZn)3O4 High-Entropy Oxide: Facile Preparation and Supercapacitor Performance

Abstract

High-entropy oxides (HEOs) have attracted more and more attention because of their unique structures and potential applications. In this work, (FeCoCrMnZn)3O4 HEO powders were synthesized via a facile solid-state reaction route. The confirmation of phase composition, the observation of microstructure, and the analysis of crystal structure, distribution of elements, and valences of elements were conducted by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS), respectively. Furthermore, a (FeCoCrMnZn)3O4/nickel foam ((FeCoCrMnZn)3O4/NF) electrode was prepared via a coating method, followed by the investigation of its supercapacitor performance. The results show that, after calcining (FeCoCrMnZn)3O4 powders at 900 °C for 2 h, a single spinel structure (FCC, Fd-3m, a = 0.8399 nm) was obtained with uniform distribution of Fe, Co, Cr, Mn, and Zn elements, the typical characteristic of a high-entropy oxide. In addition, the mass specific capacitance of the (FeCoCrMnZn)3O4/NF composite electrode was 340.3 F·g−1 (with 1 M KOH as the electrolyte and 1 A·g−1 current density), which indicates that the (FeCoCrMnZn)3O4 HEO can be regarded as a prospective candidate for an electrode material in the field of supercapacitor applications.

Inactive Al3+-doped La(CoCrFeMnNiAlx)1/(5+x)O3 high-entropy perovskite oxides as high performance supercapacitor electrodes

“…Concerning the spectrum of Mn 2p in Fig. 9(f), it can be readily observed that the main peaks at 640.9 eV (Mn 2p 3/2 ) and 652.6 eV (Mn 2p 1/2 ) are indexed to Mn 2+ species, and the peaks at 642.8 eV (Mn 2p 3/2 ) and 654.1 eV (Mn 2p 1/2 ) are related to Mn 3+ species [52]. The spectrum of Ni 2p shown in Fig.…”

Structure and magnetism of electrospun porous high-entropy (Cr1/5Mn1/5Fe1/5Co1/5Ni1/5)3O4, (Cr1/5Mn1/5Fe1/5Co1/5Zn1/5)3O4 and (Cr1/5Mn1/5Fe1/5Ni1/5Zn1/5)3O4 spinel oxide nanofibers

“…In all samples, the diffraction peaks correspond to the reflections of fcc spinel structure, belonging to Fd% 3m space group (JCPDS no. 22-1084) 51,52,56,61,[71][72][73][74][75][76] No additional peaks attributable to secondary phases are detected, indicating that a single-phase is formed for any composition, namely (Cr where k (0.9) is the shape factor, l is the wavelength of X-ray radiation, b is the FWHM in radians and y is the Bragg's angle. 77 The obtained values increase in the order CoZn (83.7 nm) o CoNi (97.0 nm) o NiZn (98.5 nm), respectively.…”

High-Entropy Oxides Prepared by Dealloying Method for Supercapacitors

“…Because Kong et al did not carry out high-temperature oxidation and used the area-specific capacitance scheme, the electrochemistry of the two materials was quite different. Compared with the HEOs with the same composition prepared by a solid-state reaction, this experiment has a similar potential window, rate, and cycle stability. However, the specific surface area of the material prepared by the dealloying scheme is enlarged to some extent; thus, the specific capacitance is improved.…”