Abstract In this study, layered Li–Ni–Co–Mn oxide (LiNi1-x-yCoxMnyO2) cathode materials with different transition metal compositions (LiNi1/3Co1/3Mn1/3O2, LiNi0.5Co0.2Mn0.3O2, and LiNi0.8Co0.1Mn0.1O2) are synthesized by a simple mixing process and solid-state reaction at a high temperature. The samples show a typical hexagonal α–NaFeO2 structure with a single phase and predominantly spherical morphology with a homogeneous particle size distribution. The electrochemical properties of the samples are investigated in different voltage ranges by galvanostatic charge/discharge tests. The results reveal that the capacity increases with increasing the charging cutoff voltage by 0.1 V for all the samples. In addition, the LiNi1/3Co1/3Mn1/3O2, LiNi0.5Co0.2Mn0.3O2 and LiNi0.8Co0.1Mn0.1O2 samples deliver initial discharge capacities of 161.0, 170.8, and 202.3 mAh g−1, respectively, at a 0.1 C rate with the voltage ranging from 3.0 to 4.3 V, which increase by 23.4%, 18.8%, and 8.2%, respectively, with the increase in the charging cutoff voltage from 4.3 to 4.6 V. Furthermore, compared with LiCoO2, the samples exhibit a relatively superior cycling performance with an increase of the charging cutoff voltage. Cyclic voltammetry tests reveal that the redox process at approximately 4.5–4.6 V corresponds to Co3+/Co4+, and that at approximately 3.6–3.8 V corresponds to Ni2+/Ni4+. X-ray diffraction measurements confirm the reversible phase transition and excellent structural stability of the LiNi1-x-yCoxMnyO2 materials against prolonged cycling.

中文翻译：

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层状Li-Ni-Co-Mn氧化物正极材料在不同电压范围内的电化学性能和结构稳定性

摘要 在本研究中，层状 Li-Ni-Co-Mn 氧化物 (LiNi1-x-yCoxMnyO2) 正极材料具有不同的过渡金属成分（LiNi1/3Co1/3Mn1/3O2、LiNi0.5Co0.2Mn0.3O2 和 LiNi0.8Co0）。 1Mn0.1O2)是通过简单的混合过程和高温固相反应合成的。样品显示出典型的六边形 α-NaFeO2 结构，具有单相和主要为球形的形态，具有均匀的粒度分布。通过恒电流充电/放电测试在不同电压范围内研究样品的电化学性能。结果表明，所有样品的容量随着充电截止电压增加 0.1 V 而增加。此外，LiNi1/3Co1/3Mn1/3O2、LiNi0.5Co0.2Mn0.3O2 和 LiNi0.8Co0.1Mn0.1O2 样品的初始放电容量分别为 161.0、170.8 和 202。3 mAh g-1，在0.1 C倍率下，电压范围从3.0到4.3 V，随着充电截止电压从4.3增加到4.6，分别增加了23.4%、18.8%和8.2% V.此外，与LiCoO2相比，随着充电截止电压的增加，样品表现出相对优越的循环性能。循环伏安测试表明，大约 4.5-4.6 V 的氧化还原过程对应于 Co3+/Co4+，而大约 3.6-3.8 V 的氧化还原过程对应于 Ni2+/Ni4+。X 射线衍射测量证实了 LiNi1-x-yCoxMnyO2 材料对长时间循环的可逆相变和优异的结构稳定性。随着充电截止电压从 4.3 V 增加到 4.6 V。此外，与 LiCoO2 相比，随着充电截止电压的增加，样品表现出相对优越的循环性能。循环伏安测试表明，大约 4.5-4.6 V 的氧化还原过程对应于 Co3+/Co4+，而大约 3.6-3.8 V 的氧化还原过程对应于 Ni2+/Ni4+。X 射线衍射测量证实了 LiNi1-x-yCoxMnyO2 材料对长时间循环的可逆相变和优异的结构稳定性。随着充电截止电压从 4.3 V 增加到 4.6 V。此外，与 LiCoO2 相比，随着充电截止电压的增加，样品表现出相对优越的循环性能。循环伏安测试表明，大约 4.5-4.6 V 的氧化还原过程对应于 Co3+/Co4+，而大约 3.6-3.8 V 的氧化还原过程对应于 Ni2+/Ni4+。X 射线衍射测量证实了 LiNi1-x-yCoxMnyO2 材料对长时间循环的可逆相变和优异的结构稳定性。大约 3.6–3.8 V 对应于 Ni2+/Ni4+。X 射线衍射测量证实了 LiNi1-x-yCoxMnyO2 材料对长时间循环的可逆相变和优异的结构稳定性。大约 3.6–3.8 V 对应于 Ni2+/Ni4+。X 射线衍射测量证实了 LiNi1-x-yCoxMnyO2 材料对长时间循环的可逆相变和优异的结构稳定性。