The high volatility of the price of cobalt and the geopolitical limitations of cobalt mining have made the elimination of Co a pressing need for the automotive industry¹. Owing to their high energy density and low-cost advantages, high-Ni and low-Co or Co-free (zero-Co) layered cathodes have become the most promising cathodes for next-generation lithium-ion batteries^2,3. However, current high-Ni cathode materials, without exception, suffer severely from their intrinsic thermal and chemo-mechanical instabilities and insufficient cycle life. Here, by using a new compositionally complex (high-entropy) doping strategy, we successfully fabricate a high-Ni, zero-Co layered cathode that has extremely high thermal and cycling stability. Combining X-ray diffraction, transmission electron microscopy and nanotomography, we find that the cathode exhibits nearly zero volumetric change over a wide electrochemical window, resulting in greatly reduced lattice defects and local strain-induced cracks. In-situ heating experiments reveal that the thermal stability of the new cathode is significantly improved, reaching the level of the ultra-stable NMC-532. Owing to the considerably increased thermal stability and the zero volumetric change, it exhibits greatly improved capacity retention. This work, by resolving the long-standing safety and stability concerns for high-Ni, zero-Co cathode materials, offers a commercially viable cathode for safe, long-life lithium-ion batteries and a universal strategy for suppressing strain and phase transformation in intercalation electrodes.

钴价格的高波动性和钴开采的地缘政治限制使得淘汰钴成为汽车行业的迫切需求¹。由于其高能量密度和低成本优势，高镍低钴或无钴（零钴）层状正极已成为下一代锂离子电池最有前途的正极^2,3。然而，目前的高镍正极材料无一例外地严重受到其固有的热和化学机械不稳定性以及循环寿命不足的影响。在这里，通过使用一种新的成分复杂（高熵）掺杂策略，我们成功制造了具有极高热稳定性和循环稳定性的高镍、零钴层状阴极。结合X射线衍射、透射电子显微镜和纳米断层扫描，我们发现阴极在很宽的电化学窗口内表现出几乎为零的体积变化，从而大大减少了晶格缺陷和局部应变引起的裂纹。原位加热实验表明，新型阴极的热稳定性显着提高，达到超稳定NMC-532的水平。由于热稳定性显着提高且体积变化为零，其容量保持率大大提高。这项工作通过解决高镍、零钴正极材料长期存在的安全性和稳定性问题，为安全、长寿命的锂离子电池提供了商业上可行的正极，并为抑制应变和相变提供了一种通用策略。嵌入电极。