High-Entropy Oxides Prepared by Dealloying Method for Supercapacitors

Abstract

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.

A Novel High Entropy Hydroxide Electrode Material for Promoting Energy Density of Supercapacitors and Its Efficient Synthesis Strategy

“…[37] By etching FeCoNiCrMnAl 95 alloy, Zhang et al obtained (FeCoNiCrMn) 3 O 4 electrode material, which has a specific capacitance of 639 F g −1 at the current density of 1 A g −1 . [38] Sreenivasala et al adopted reverse coprecipitation and high-temperature oxidation to prepare (Al 0.2 Cr 0.2 Co 0.2 Mn 0.2 Ni 0.2 ) 3 O 4 , and the specific capacitance of the material was 318 mAh g −1 (at the current density of 1 A g −1 ). [39] There is no doubt that high entropy compounds have certain advantages as electrode materials in the supercapacitor field.…”

“…obtained (FeCoNiCrMn) 3 O 4 electrode material, which has a specific capacitance of 639 F g −1 at the current density of 1 A g −1 . [ 38 ] Sreenivasala et al. adopted reverse coprecipitation and high‐temperature oxidation to prepare (Al 0.2 Cr 0.2 Co 0.2 Mn 0.2 Ni 0.2 ) 3 O 4 , and the specific capacitance of the material was 318 mAh g −1 (at the current density of 1 A g −1 ).…”

Future prospects of high-entropy alloys as next-generation industrial electrode materials

“…Fig.25 (a-c) Capacitive contribution, separations of diffusion-controlled and capacitive charges at different scan rates, and cycling performances of (FeCoNiCrMn) 3 O 4 /NF and CoCr 2 O 4 /NF. Reproduced with permission 332. Copyright 2023, American Chemical Society.…”

“…et al synthesized (FeCoNiCrMn)3 -O 4 by dealloying the FeCoNiCrMnAl 95 alloy in 3 M NaOH, achieving superior supercapacitor characteristics as an anode material, with a specic capacitance of 639 F g −1 at 1 A g −1 and retention of 80.77% at 10 A g −1 332. The reduction peak occurs at 0.3 V, which is predominantly caused by the transition-metal oxide reduction (M 4+ /M 3+ to M 2+ , M 2+ to M 0 ), indicating that the materials rely on noticeable redox reactions for energy storage.…”