Stabilization, Characterization, and Electrochemical Applications of High-Entropy Oxides: Critical Assessment of Crystal Phase–Properties Relationship

Gracita M. Tomboc, Xiandi Zhang, Songa Choi, Daekyu Kim, Lawrence Yoon Suk Lee, Kwangyeol Lee

Research output: Contribution to journalReview articlepeer-review

30 Citations (Scopus)


High-entropy oxides (HEOs), a class of newly emerging energy conversion and storage technology materials, have gained significant interest due to their unique structure, complex stoichiometry, and corresponding synergetic effect. Despite the increasing number of reported studies related to HEOs in recent years, details of their structural properties and electrochemical activities are still lacking. Herein, the exciting developments of HEOs regarding their design, synthesis, characterization, theoretical calculations, and electrochemical performances are outlined. The fundamentals of HEOs, including their strict definition, main features, and four-core aspect effects are presented. The different synthetic methods of HEOs are categorized to highlight the significance of parameter optimization to ensure the single-phase stability of HEOs. The advances in characterization techniques on the local lattice and atomic distribution and the basic principles of combinatorial screening methods based on computational techniques are also elaborated. Recent HEO-based electrode/electrocatalysts toward Li-ion batteries and oxygen catalysis are reviewed to assess the potential applications of HEOs. This review draws attention to the critical challenges of HEOs that are worth more extensive explorations in the future.

Original languageEnglish
Article number2205142
JournalAdvanced Functional Materials
Issue number43
Publication statusPublished - 2022 Oct 21

Bibliographical note

Funding Information:
G.M.T., X.Z., S.C., and D.K. contributed equally to this work. This work was supported by the National Research Foundation of Korea (NRF‐2020R1A2B5B03002475 and NRF‐2021M3H4A1A02049916), Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government (MOTIE), Grant No. 20203020030010, Research Grants Council of the Hong Kong SAR, China (PolyU15217521) and the Hong Kong Polytechnic University (Q‐CDA3).

Publisher Copyright:
© 2022 Wiley-VCH GmbH.


  • combinatorial screening approach
  • energy conversion
  • energy storage
  • high-entropy oxides
  • phase stability
  • structural characterization

ASJC Scopus subject areas

  • General Chemistry
  • General Materials Science
  • Condensed Matter Physics


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