LiClO4预氧化Ni0.8Co0.17Al0.03(OH)2提升锂离子电池的循环稳定性

层状高镍正极材料（LiNi_0.8Co_0.17Al_0.03O₂）因为具有高的镍含量，相比于LiCoO₂拥有更高的比容量和更低的成本，受到了大众的欢迎。然而，循环过程中容量的快速衰退阻碍了LiNi_0.8Co_0.17Al_0.03O₂的进一步商业化使用。其中，Li+/Ni2+混排现象是造成材料不良循环性能的主要原因之一。本文中，使用具有强氧化性的LiClO₄对Ni_0.8Co_0.17Al_0.03（OH）₂前驱体进行预氧化处理。X射线衍射（XRD）测试和精修结果显示，LiClO₄处理后的LiNi_0.8Co_0.17Al_0.03O₂（LiClO₄-NCA）样品有着更低的Li+/Ni2+混排程度，这与X射线光电子能谱（XPS）测试得到的正极材料中Ni2+/Ni3+结果相一致。电化学测试结果显示，LiClO₄-NCA相比于原始样品LiNi_0.8Co_0.17Al_0.03O₂（NCA）具有更优异的循环性能，1 C倍率循环100圈后，LiClO₄-NCA的容量保持率（94.3%）明显高于NCA（82.4%）。LiClO₄-NCA优异的电化学性能归因于LiClO₄促进了材料中的Ni2+转化为Ni3+，减少了阳离子混排现象，保持了更完整的层状结构。因此，LiClO₄对Ni_0.8Co_0.17Al_0.03（OH）₂前驱体进行预氧化处理可以改善材料中的Li+/Ni2+混排现象，优化层状高镍正极材料的循环稳定性。 

Preoxidation of Ni0.8Co0.17Al0.03(OH)2 with LiClO4 to improve cycle stability of lithium-ion batteries

Layered Ni-rich anode material (LiNi_0.8Co_0.17Al_0.03O₂) is welcomed by the public because of its high nickel content, higher specific capacity and lower cost than LiCoO₂. However, the rapid capacity decline in the process of cycling prevents further commercial application of LiNi_0.8Co_0.17Al_0.03O₂. Among them, the mixing of Li+ /Ni2+ in Ni-rich anode materials is one of the main reasons for the poor cycle performance of materials. In this paper, LiNi_0.8Co_0.17Al_0.03O₂ precursor was preoxidized with highly oxidized LiClO₄. The X-ray diffraction (XRD) and Rietveld refinement results show that the LiNi_0.8Co_0.17Al_0.03O₂ (LiClO₄-NCA) sample after LiClO₄ treatment has a lower Li+/Ni2+ mixing degree, which is consistent with the results of Ni2+/Ni3+ in the anode material tested by X-ray photoelectron spectroscopy (XPS). The electrochemical test results show that LiClO₄-NCA has better cycling performance than the original sample LiNi_0.8Co_0.17Al_0.03O₂ (NCA). The capacity retention rate of LiClO₄-NCA (94.3%) is significantly higher than that of NCA (82.4%) after 100 cycles of 1 C. The excellent electrochemical performance of LiClO₄-NCA is attributed to the fact that LiClO₄ promotes the conversion of Ni2+ into Ni3+ in the material, reducing cation mixing phenomenon and maintaining a more complete layered structure. Therefore, LiClO₄ preoxidation of LiNi_0.8Co_0.17Al_0.03O₂ precursor can improve the mixing phenomenon of Li+/Ni2+ in the material and optimize the cycle stability of layered Ni-rich anode material.