High-Entropy Oxides Prepared by Dealloying Method for Supercapacitors

High-entropy oxides (HEOs) are materials with a multielement mixture and a stable structure, which are widely used in energy storage due to their electrochemical properties. For application to supercapacitors, the method of preparation of HEOs needs to be improved, and the energy storage mechanism of the material needs to be investigated. In this experiment, 3 M NaOH was used to etch the FeCoNiCrMnAl95 alloy, and then (FeCoNiCrMn)3O4 was successfully produced by a facile oxidation treatment. HRTEM images show that the materials have a porous structure, and EDS mapping suggests that the individual elements are evenly distributed. The XRD and SAED patterns indicate that it has a stable crystal structure. The HEOs prepared by dealloying exhibited excellent supercapacitor characteristics, with a specific capacitance of 639 F/g at 1 A/g and retention of 80.77% at 10 A/g. Density functional theory (DFT) simulations back up this excellent energy storage capability. This work offers a novel method for manufacturing HEOs and a solid option for supercapacitor anode materials.