Nickel (Ni)-rich layered oxide cathodes are essential energy materials for high-energy-density lithium-ion batteries owing to their high theoretical capacity. However, they are prone to serious structural collapse and an unstable cathode electrolyte interphase (CEI). Herein, we report a facile and novel hybrid organic–inorganic polyurea (HPU) coating to modify the surface of the LiNi_0.94Co_0.05Mn_0.01O₂ (Ni94) cathode via molecular layer deposition (MLD). Serving as a robust protective barrier, the HPU coating effectively suppresses cathode–electrolyte side reactions and promotes the formation of an ultra-thin CEI. Simultaneously, the mechanically stable and ‘breathable’ HPU coating maintains the integrity of cathode particles during charge/discharge without inducing serious cracking. Moreover, the stabilized CEI prevents further crack-induced interphase degradation and near-surface phase transformation, suppressing the variation in the chemical state and local environment of Ni. As a result, the surface-modified cathode can maintain 94.9% of its initial capacity in 200 cycles. This work highlights the importance of interphase engineering and outlines a new pathway towards forming a high-energy and stable Ni-rich layered cathode.

中文翻译：

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透气的无机-有机界面，用于制造具有长期稳定性的无裂纹富镍阴极


富镍（Ni）层状氧化物正极由于其高理论容量而成为高能量密度锂离子电池的重要能源材料。然而，它们容易出现严重的结构崩溃和不稳定的阴极电解质界面（CEI）。在此，我们报道了一种简便新颖的杂化有机-无机聚脲（HPU）涂层，用于修饰LiNi _0.94 Co _0.05 Mn _0.01 O (Ni94) 阴极通过分子层沉积 (MLD) 实现。 HPU 涂层作为坚固的保护屏障，有效抑制阴极电解质副反应并促进超薄 CEI 的形成。同时，机械稳定且“透气”的 HPU 涂层可在充电/放电过程中保持阴极颗粒的完整性，而不会引起严重的开裂。此外，稳定的CEI可以防止进一步裂纹引起的相间退化和近表面相变，从而抑制Ni化学状态和局部环境的变化。结果，表面改性正极在200次循环后仍能保持其初始容量的94.9%。这项工作强调了相间工程的重要性，并概述了形成高能且稳定的富镍层状阴极的新途径。