Ni-rich cathode, recognized for high specific capacities and cost-effectiveness, are deemed promising candidates for high-energy Li-ion batteries. However, these cathodes display notable structural instability and experience severe strain propagation during rapid charging and extended cycling under high voltage, hindering their widespread commercialization. To tackle this chemo-mechanical instability without compromising energy and power density, we propose an efficient modification strategy involving hexavalent metal cation-induced three-in-one modification to reconstruct the nanoscale surface phase. This strategy includes uniform W-doping, integration of cation-mixed phases, and Li2WO4 nanolayers on the surface of Ni-rich cathode microspheres. W-doping strengthen the bond to oxygen, thereby enhancing structural stability and suppressing oxygen loss linked to a layered-to-rock salt phase transition during deep delithiation process. Additionally, establishing a cation-mixing domain with an optimal thickness on the cathode surface enhances Li⁺ diffusivity and alleviates particle structural degradation. Moreover, Li2WO4 nanolayers reduce electrolyte side reactions and act as a damping medium against cycling stresses. Importantly, detailed investigations into structural changes before and after modification at varying current rates were conducted to better comprehend the rate-dependent degradation mechanism. These findings yield valuable mechanistic insights into the high-rate utilization of a viable Ni-rich cathode, ensuring prolonged service life in electric vehicles.

中文翻译：

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通过三合一改性提高锂离子电池富镍正极的化学机械稳定性和高速倍率性能


富镍阴极以其高比容量和成本效益而著称，被认为是高能锂离子电池的有前途的候选者。然而，这些阴极表现出明显的结构不稳定性，并在快速充电和高压下延长循环过程中经历严重的应变传播，阻碍了它们的广泛商业化。为了在不影响能量和功率密度的情况下解决这种化学机械不稳定性，我们提出了一种有效的改性策略，涉及六价金属阳离子诱导的三合一改性来重建纳米级表面相。该策略包括均匀的 W 掺杂、阳离子混合相的整合以及富镍阴极微球表面的 Li2WO4 纳米层。W 掺杂增强了与氧的键合，从而增强了结构稳定性并抑制了与深度脱锂过程中层状到岩盐相变相关的氧损失。此外，在阴极表面建立具有最佳厚度的阳离子混合结构域可增强 Li⁺ 扩散率并减轻颗粒结构退化。此外，Li2WO4 纳米层可减少电解质副反应，并作为抵抗循环应力的阻尼介质。重要的是，对不同电流速率下改性前后的结构变化进行了详细研究，以更好地理解速率依赖性降解机制。这些发现为可行的富镍阴极的高倍率利用提供了宝贵的机械见解，从而确保延长电动汽车的使用寿命。