3D-Mixer-Assisted High-Entropy Doping of LiNiO2 for Co-Free Ni-Rich Cathodes in Lithium-Ion Batteries.

ABSTRACT The development of Co‐free, Ni‐rich cathodes is critical to overcoming cost and sustainability challenges in lithium‐ion batteries. Here, we propose a high‐entropy doping strategy for LiNiO 2 by uniformly incorporating Mn, Al, Fe, Mg, and Cr into the transition‐metal layer through a scalable 3D mixing process. Each dopant plays a complementary role in stabilizing the layered structure and enhancing electrochemical performance. The resulting Li 1.05 Ni(MnAlFeMgCr) 0.10 O 2 suppresses Li/Ni cation mixing, strengthens TM─O bonding, mitigates polarization and diffusion bottlenecks, and reduces electrode swelling (from 23% in pristine LNO to 16%). The high‐entropy‐doped cathode delivered a capacity retention of 79% after 100 charge–discharge cycles at 0.3 C, markedly surpassing that of pristine LNO (51%). These results demonstrate that high‐entropy doping effectively improves structural robustness and long‐term durability, offering a practical pathway to economically viable and sustainable next‐generation Co‐free Ni‐rich layered cathodes.