Charge–Discharge Mechanism of High-Entropy Co-Free Spinel Oxide Toward Li+ Storage Examined Using Operando Quick-Scanning X-Ray Absorption Spectroscopy

Xu Feng Luo, Jagabandhu Patra, Wei Tsung Chuang, Thi Xuyen Nguyen, Jyh Ming Ting, Ju Li, Chih Wen Pao, Jeng Kuei Chang

研究成果: Article同行評審

1 引文 斯高帕斯(Scopus)

摘要

Transition metal high-entropy oxides (HEOs) are an attractive class of anode materials for high-performance lithium-ion batteries (LIBs). However, owing to the multiple electroactive centers of HEOs, the Li+ storage mechanism is complex and debated in the literature. In this work, operando quick-scanning X-ray absorption spectroscopy (XAS) is used to study the lithiation/delithiation mechanism of the Cobalt-free spinel (CrMnFeNiCu)3O4 HEO. A monochromator oscillation frequency of 2 Hz is used and 240 spectra are integrated to achieve a 2 min time resolution. High-photon-flux synchrotron radiation is employed to increase the XAS sensitivity. The results indicate that the Cu2+ and Ni2+ cations are reduced to their metallic states during lithiation but their oxidation reactions are less favorable compared to the other elements upon delithiation. The Mn2+/3+ and Fe2+/3+ cations undergo two-step conversion reactions to form metallic phases, with MnO and FeO as the intermediate species, respectively. During delithiation, the oxidation of Mn occurs prior to that of Fe. The Cr3+ cations are reduced to CrO and then Cr0 during lithiation. A relatively large overpotential is required to activate the Cr reoxidation reaction. The Cr3+ cations are found after delithiation. These results can guide the material design of HEOs for improving LIB performance.

原文English
文章編號2201219
期刊Advanced Science
9
發行號21
DOIs
出版狀態Published - 2022 7月 25

All Science Journal Classification (ASJC) codes

  • 醫藥(雜項)
  • 化學工程 (全部)
  • 材料科學(全部)
  • 生物化學、遺傳與分子生物學(雜項)
  • 工程 (全部)
  • 物理與天文學 (全部)

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