Microstructure Engineered Ultrahigh-Nickel Cathode With Enhanced Mechanical Strength and Cycle Performance

In ultrahigh-nickel layered cathode materials, regulating the morphology and arrangement of primary particles is a strategy that effectively to mitigate particle microcrack formation and enhance structural stability during electrochemical cycling. Nevertheless, current investigations on Ta-doped cathodes have primarily focused on the relationships between primary particle morphology, size distribution, and electrochemical performance. The fundamental mechanisms by which Ta doping influences primary-particle evolution, lattice microstrain, stress redistribution during electrochemical cycling, mechanical strength, and structural stability remain poorly understood. In this work, a Ta doping strategy was employed to engineer the microstructure of LiNi_0.90Co_0.05Mn_0.05O₂ cathodes, resulting in refined and radially aligned primary particles. The results reveal that LiNi_0.90Co_0.05Mn_0.05O₂ containing 0.5 mol% Ta exhibits refined radially aligned primary particles, reduced lattice microstrain, possessed more homogeneous stress distribution, and diminished strain fluctuations during cycling, which collectively contribute to enhanced mechanical strength and improved cycling stability. This work establishes the correlations among microstructural characteristics, chemo-mechanical behavior, and electrochemical performance laying the foundation for the rational design of high-stability Ni-rich layered cathodes.