Nanoscale high-entropy alloys and oxides for supercapacitor electrodes: size effects, structure-property relationships, and energy storage potential


Gungor A., Saritas E., Toloman D., Popa A., Rostas A. M., Erdem E.

NANOSCALE, 2025 (SCI-Expanded, Scopus) identifier identifier

  • Publication Type: Article / Review
  • Publication Date: 2025
  • Doi Number: 10.1039/d5nr04044b
  • Journal Name: NANOSCALE
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Chimica, Compendex, INSPEC, MEDLINE
  • Middle East Technical University Affiliated: Yes

Abstract

High-entropy alloys and oxides (HEAs and HEOs), composed of multiple principal elements in near-equiatomic ratios, have emerged as promising candidates for supercapacitor electrodes. Their intrinsic features-configurational entropy stabilization, sluggish diffusion, and lattice distortion-enable unique structure-property relationships. When synthesized at the nanoscale, these materials exhibit enhanced surface area, high defect density, and finite-size effects that boost electrochemical activity and stability. This review outlines the evolution of high-entropy materials, their synthesis strategies, and the advantages of nanoscale design for energy storage. We highlight correlations between electronic structure, defect engineering, charge storage mechanisms, and device-level demonstrations in symmetric, asymmetric, and flexible supercapacitors. Remaining challenges include synthesis reproducibility, compositional control, and scalability, while emerging directions point toward hybrid composites, sustainable synthesis, and artificial intelligence-guided discovery. Nanoscale high-entropy alloys and oxides thus provide a versatile platform to advance supercapacitor performance through systematic tuning of size effects and structure-property relationships.