Making 1000 Wh/kg LiNiO2 Cathode Nearly Strain-Free by Complex-Concentrated Doping
Yaqi Jing, Zhen Wang, Rui Zhang, Lei Wang, Zhennan Chen, Lu Ma, Dali Yang, Mingyuan Ge, Iradwikanari Waluyo, Adrian Hunt, Hui Zhong, Stephen E. Trask, Mingyuan Xue, Huolin L. XinAbstract
High-energy batteries require cathodes with greater capacity and specific energy. Ni-rich-layered oxides approach the performance limit of LiNiO2 (LNO), yet its practical use is hindered by severe chemomechanical degradation. Near 4.2 V, the H2-H3/H4 transition drives substantial c-axis contraction, volume shrinkage, O1 formation, oxygen loss, and rapid capacity decay. Here, we show that only 5% cobalt-free complex concentrated doping stabilizes LNO without sacrificing energy density. The modified LNO reduces c-axis strain from 7.4 to 2.1%, exhibits near-zero-strain behavior, and delivers 258 mAh•g–1 and 973 Wh•kg–1. In pouch cells, it retains 80% capacity after 1800 cycles and shows markedly improved thermal stability. These results demonstrate that complex-concentrated doping at low dopant loading can suppress strain and phase transformations at the full-Ni limit, providing a broadly applicable strategy for stabilizing high-energy intercalation electrodes while preserving their intrinsic capacity and specific energy during prolonged electrochemical cycling.