Abstract: A modified LiNiO₂ cathode material (Zr-LNO@LA) was synthesized through Zr⁴⁺ doping into the bulk phase of the Ni(OH)₂ precursor using the co-precipitation method, followed by coating LaAlO₃ and its derivative La₂Li_0.5Al_0.5O₄ onto the Zr-doped Ni(OH)₂ precursor in a single lithiation step via the high-temperature solid-state method. This modification strategy effectively addresses the persistent challenges of continuous capacity fading and service life degradation observed in LiNiO₂ (LNO) cathode materials during cycling, which are primarily attributed to interface and structural instability. Comprehensive structural characterization and electrochemical testing reveal that this modification approach increases the unit cell parameters of LNO, reduces the extent of Li⁺/Ni²⁺ cation mixing, enhances the stability of lattice oxygen, and improves the overall structural stability of the cathode material. Additionally, the residual lithium content is significantly reduced, and interface stability is markedly strengthened. The Zr-LNO@LA cathode material exhibits a substantial improvement in initial discharge Coulombic efficiency and rate capability. Furthermore, its cycling performance is considerably enhanced, maintaining excellent stability after 200 cycles at 1 C and 500 cycles at 5 C.