Lattice stability-induced enhanced performance of a quasi-single-crystal LiNi0.75Co0.1Mn0.15O2 cathode for lithium-ion batteries

Abstract

Ni-rich layered cathode materials have become a research hotspot due to their high theoretical specific capacity. However, Li⁺/Ni²⁺ mixing is a critical factor affecting their applicability. Doping is an important method employed to improve the electrochemical performance of ternary layered cathode materials. In this work, kilogram-scale quasi-single-crystal LiNi_0.75Co_0.1Mn_0.15O₂ with different Al-doping contents was synthesized via a solid-phase method combined with segmented sintering. The results of X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy analyses, as well as the electrochemical performance, were thoroughly discussed. Electrochemical test data showed that, under a 4.3 V cut-off voltage, the Al-doped sample exhibited a capacity retention rate of 91.37% after 100 cycles at 0.5 C, significantly higher than that of the undoped sample (75.86%). The improved performance was primarily attributed to reduced Li⁺/Ni²⁺ mixing, suppressed phase transitions, and decreased potential polarization and impedance.