Regulating Primary Particle Morphology and Li/Ni Disorder via Calcination Temperature for Enhanced Electrochemical Performance in Cobalt-Free Nickel-Rich Layered Cathodes

Cobalt-free and nickel-rich (CFNR) layered oxides are promising cathode materials for lithium-ion batteries, offering high capacity and cost-efficiency. However, Li/Ni disorder during synthesis impedes their practical application. In this study, varying degrees of Li/Ni disorder were introduced into LiNi0.9Mn0.1O2 (LNM91) cathodes by adjusting the calcination temperature. Results indicate that minimal Li/Ni disorder optimizes initial charge and discharge capacities, while a moderate degree of disorder enhances rate capability and cycling stability. This enhancement is attributed to antisite Ni2+ ions, which serve as structural pillars within the Li layer, improving material stability. This material calcinated at 700 °C (named as LNM91–700), with 14.85% Li/Ni disorder, retains 96.05% of its capacity after 100 cycles at 0.5 C and maintains 175.15 mAh g–1 at 5 C, demonstrating superior cycling performance and rate capability. Full-cell tests reveal that a 4.4 V cutoff voltage optimizes both capacity and cycling stability. This work offers valuable insights into the design of calcination processes and the electrochemical optimization of CFNR materials.