Defect-Driven Configurational Entropy in the High-Entropy Oxide Li 1.5 MO 3-δ

• Published in: Nano letters 2024-07, Vol.24 (28), p.8495-8501
• Main Authors: Mansley, Zachary R, Huang, Cynthia, Luo, Jessica, Barry, Patrick, Rodriguez-Campos, Armando, Millares, Marie F, Wang, Zhongling, Ma, Lu, Ehrlich, Steven N, Takeuchi, Esther S, Marschilok, Amy C, Yan, Shan, Takeuchi, Kenneth J, Zhu, Yimei
• Format: Article
• Language: English
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/acs.nanolett.4c00551

Layered lithiated oxides are promising materials for next generation Li-ion battery cathode materials; however, instability during cycling results in poor performance over time compared to the high capacities theoretically possible with these materials. Here we report the characterizations of a Li Mn Al Fe Co Ni O high-entropy layered oxide (HELO) with the Li MO structure where M = Mn, Al, Fe, Co, and Ni. Using electron microscopy and X-ray spectroscopy, we identify a homogeneous Li MO structure stabilized by the entropic contribution of oxygen vacancies. This defect-driven entropy would not be attainable in the LiMO structure sometimes observed in similar materials as a secondary phase owing to the presence of fewer O sites and a 3+ oxidation state for the metal site; instead, a Li MO is produced. Beyond Li MO , this defect-driven entropy approach to stabilizing novel compositions and phases can be applied to a wide array of future cathode materials including spinel and rock salt structures.