Oxygen release and electrolyte decomposition under high voltage endlessly exacerbate interfacial ramifications and structural degradation of high energy-density Li-rich layered oxide (LLO), leading to voltage and capacity fading. Herein, the dual-strategy of CrxB complex coating and local gradient doping is simultaneously achieved on LLO surface by a one-step wet chemical reaction at room temperature. Density functional theory (DFT) calculations prove that stable B–O and Cr–O bonds through the local gradient doping can significantly reduce the high-energy O 2p states of interfacial lattice O, which is also effective for the near-surface lattice O, thus greatly stabilizing the LLO surface. Besides, differential electrochemical mass spectrometry (DEMS) indicates that the CrxB complex coating can adequately inhibit oxygen release and prevents the migration or dissolution of transition metal ions, including allowing speedy Li+ migration. The voltage and capacity fading of the modified cathode (LLO-CrB) are adequately suppressed, which are benefited from the uniformly dense cathode electrolyte interface (CEI) composed of balanced organic/inorganic composition. Therefore, the specific capacity of LLO-CrB after 200 cycles at 1C is 209.3 mA h g−1 (with a retention rate of 95.1%). This dual-strategy through a one-step wet chemical reaction is expected to be applied in the design and development of other anionic redox cathode materials.

中文翻译：

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可实现的双重策略，通过一步湿化学反应实现长氧氧化还原可逆性，稳定富锂层状氧化物界面


高压下的氧释放和电解质分解无休止地加剧了高能量密度富锂层状氧化物 （LLO） 的界面分化和结构退化，导致电压和容量衰减。在此，通过在室温下通过一步湿化学反应在 LLO 表面同时实现 CrxB 复合涂层和局部梯度掺杂的双重策略。密度泛函理论 （DFT） 计算证明，通过局部梯度掺杂稳定的 B-O 和 Cr-O 键可以显著降低界面晶格 O 的高能 O 2p 状态，这对近表面晶格 O 也有效，从而大大稳定了 LLO 表面。此外，差分电化学质谱 （DEMS） 表明 CrxB 复合涂层可以充分抑制氧的释放并防止过渡金属离子的迁移或溶解，包括允许快速的 Li+ 迁移。改性阴极 （LLO-CrB） 的电压和容量衰落得到充分抑制，这得益于由平衡的有机/无机组成组成的均匀致密的阴极电解质界面 （CEI）。因此，在 1C 下循环 200 次后，LLO-CrB 的比容量为 209.3 mA h g-1（保留率为 95.1%）。这种通过一步湿化学反应的双策略有望应用于其他阴离子氧化还原正极材料的设计和开发。