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<p>Li-rich layered cathode materials are considered to be the most promising cathode materials for high energy density Li-ion batteries due to its high capacity. However, oxygen evolution leads to serious failure problems and hinders its wide application. To disclose the mechanism of oxygen evolution, the lattice distortion and thermodynamic stability of lattice oxygen in Li-rich layered cathode materials Li<sub>1.25-<i>x</i></sub>Ni<sub>0.5</sub>Mn<sub>0.25</sub>O<sub>2</sub> are investigated by employing first-principles computational methods in this work. The results show that the change of lattice volume is mainly related to the expansion or collapse of the cell in the z-direction. In the ground state, oxygen vacancies (O-vacancies) easily occur when the Li content is below 0.7. The formation of O-vacancies in cathode materials is closely related to temperature and oxygen partial pressure. Increasing the temperature promotes the formation of O-vacancies. However, increasing the oxygen partial pressure is favorable to suppress the formation of O-vacancies. This study provides a theoretical basis for the design of Li-rich cathodes with high stability.</p>

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A study of the thermodynamic stability of lattice oxygen in Li-rich cathode Li1.25Ni0.5Mn0.25O2 during operation

  • 期刊论文

  • 发表日期：

    2025年4月16日

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  • Huiyuan Chen,
  • Chunhua Shu,
  • Hao Deng,
  • Kerong He,
  • Wei Hu

摘要

Li-rich layered cathode materials are considered to be the most promising cathode materials for high energy density Li-ion batteries due to its high capacity. However, oxygen evolution leads to serious failure problems and hinders its wide application. To disclose the mechanism of oxygen evolution, the lattice distortion and thermodynamic stability of lattice oxygen in Li-rich layered cathode materials Li1.25-xNi0.5Mn0.25O2 are investigated by employing first-principles computational methods in this work. The results show that the change of lattice volume is mainly related to the expansion or collapse of the cell in the z-direction. In the ground state, oxygen vacancies (O-vacancies) easily occur when the Li content is below 0.7. The formation of O-vacancies in cathode materials is closely related to temperature and oxygen partial pressure. Increasing the temperature promotes the formation of O-vacancies. However, increasing the oxygen partial pressure is favorable to suppress the formation of O-vacancies. This study provides a theoretical basis for the design of Li-rich cathodes with high stability.