Lithium ion batteries are encountering ever-growing demand for further increases in energy density. Li-rich layered oxides are considered a feasible solution to meet this demand because their specific capacities often surpass 200 mAh g^-1 due to the additional lithium occupation in the transition metal layers. However, this lithium arrangement, in turn, triggers cation mixing with the transition metals, causing phase transitions during cycling and loss of reversible capacity. Here we report a Li-rich layered surface bearing a consistent framework with the host, in which nickel is regularly arranged between the transition metal layers. This surface structure mitigates unwanted phase transitions, improving the cycling stability. This surface modification enables a reversible capacity of 218.3 mAh g^-1 at 1C (250 mA g^-1) with improved cycle retention (94.1% after 100 cycles). The present surface design can be applied to various battery electrodes that suffer from structural degradations propagating from the surface.

中文翻译：

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用于富含锂的分层阴极材料的稳定的富含锂的表面结构。

锂离子电池正面临着不断增长的能量密度进一步增长的需求。富锂的层状氧化物被认为是满足该需求的可行解决方案，因为由于过渡金属层中额外的锂占据，它们的比容量通常超过200 mAh g ^-1。但是，这种锂排列反过来会引发阳离子与过渡金属的混合，从而在循环过程中引起相变，并降低可逆容量。在这里，我们报告了一个富含锂的分层表面，该表面与主体保持一致的框架，其中镍定期排列在过渡金属层之间。这种表面结构减轻了不必要的相变，提高了循环稳定性。这种表面修饰可实现218.3 mAh g ^-1的可逆容量在1C（250 mA g ^-1）时具有更好的循环保持率（100个循环后为94.1％）。本表面设计可以应用于遭受从表面传播的结构劣化的各种电池电极。