Journal of Energy Chemistry ›› 2023, Vol. 86 ›› Issue (11): 536-545.DOI: 10.1016/j.jechem.2023.06.041

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Molten salt synthesis, morphology modulation, and lithiation mechanism of high entropy oxide for robust lithium storage

Xuefeng Liua, Honghong Wanga, Long Donga, Kezhuo Lia, Haijun Zhanga,*, Quanli Jiab, Shaowei Zhangc, Wen Leia,d,*   

  1. aThe State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081, Hubei, China;
    bHenan Key Laboratory of High Temperature Functional Ceramics, Zhengzhou University, Zhengzhou 450052, Henan, China;
    cCollege of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter EX4 4QF, UK;
    dKey Laboratory of Advanced Energy Materials Chemistry (Ministry of Education), Nankai University, Tianjin 300071, China
  • Received:2023-05-24 Revised:2023-06-25 Accepted:2023-06-28 Online:2023-11-15 Published:2023-11-07
  • Contact: *E-mail addresses: zhanghaijun@wust.edu.cn (H. Zhang), leiwen@wust.edu.cn (W. Lei).

Abstract: High entropy oxides (HEOs) with ideal element tunability and enticing entropy-driven stability have exhibited unprecedented application potential in electrochemical lithium storage. However, the general control of dimension and morphology remains a major challenge. Here, scalable HEO morphology modulation is implemented through a salt-assisted strategy, which is achieved by regulating the solubility of reactants and the selective adsorption of salt ions on specific crystal planes. The electrochemical properties, lithiation mechanism, and structure evolution of composition- and morphology-dependent HEO anode are examined in detail. More importantly, the potential advantages of HEOs as electrode materials are evaluated from both theoretical and experimental aspects. Benefiting from the high oxygen vacancy concentration, narrow band gap, and structure durability induced by the multi-element synergy, HEO anode delivers desirable reversible capacity and reaction kinetics. In particular, Mg is evidenced to serve as a structural sustainer that significantly inhibits the volume expansion and retains the rock salt lattice. These new perspectives are expected to open a window of opportunity to compositionally/morphologically engineer high-performance HEO electrodes.

Key words: High-entropy oxide, Lithium-ion battery anode, Molten salt, Morphology modulation, Structure stability