Spinel-Structured High Entropy Oxides: Low Temperature Synthesis, Characterization, and Potential Applications

ALGAN ŞİMŞEK İ. B., Badr H. O., Cardoza N., Colin-Ulloa E., Schwenk G. R., Sudhakar K., ...More

ACS OMEGA, vol.10, no.35, pp.39530-39539, 2025 (SCI-Expanded, Scopus)

  • Publication Type: Article / Article
  • Volume: 10 Issue: 35
  • Publication Date: 2025
  • Doi Number: 10.1021/acsomega.5c00902
  • Journal Name: ACS OMEGA
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Directory of Open Access Journals
  • Page Numbers: pp.39530-39539
  • Gazi University Affiliated: Yes

Abstract

High entropy oxides (HEOs) have recently attracted increasing attention due to their remarkable properties and relatively low cost. Herein we report a simple, highly scalable, and low temperature method for synthesizing spinel (FeNiCoCuZn)3O4 (HEO). We heated an aqueous solution containing divalent cations in high alkali environments to temperatures of 25 - 95 degrees C for 24 h under atmospheric pressure. The HEO, synthesized at 95 degrees C for 24 h in 1 M KOH, was paramagnetic at room temperature, with a magnetic mass susceptibility of chi = (7.5 +/- 0.2) x 10-7 m3kg-1. It demonstrated stable electrochemical lithium storage performance, with a gravimetric capacity of similar to 300 mAhg-1 at 100 mAg- 1. It was also active in the electrocatalytic oxygen evolution reaction with an overpotential of 460 mV in alkaline media. The band gap energies were in the range of 2.4 eV. Our advancement in the synthesis and processing of transition metal-based HEOs will undoubtedly render them a viable solution for next generation materials for energy production and storage.