3D‐Mixer‐Assisted High‐Entropy Doping of LiNiO 2 for Co‐Free Ni‐Rich Cathodes in Lithium‐Ion Batteries
Seung Ri Kim, Thillai Govindaraja Senthamaraikannan, Jun Jae Myeong, Hyung Do Kim, Dong‐Hee Lim, Eun Mi Kim, Sang Mun JeongABSTRACT
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.