Electrochemical Performances of Nickel-Rich Single-Crystal LiNi_0.83Co_0.12Mn_0.05O₂ Cathode Material for Lithium-Ion Batteries Synthesized by Tuning Li⁺/Ni²⁺ Mixing

Single-crystal nickel-rich materials are promising alternatives to polycrystalline cathodes owing to their excellent structure stability and cycle performance while the cathode material usually appears high cation mixing, which may have a negative effect on its electrochemical performance. The study presents the structural evolution of single-crystal LiNi_0.83Co_0.12Mn_0.05O₂ in the temperature–composition space using temperature-resolved in situ XRD and the cation mixing is tuned to improve electrochemical performances. The as-synthesized single-crystal sample shows high initial discharge specific capacity (195.5 mAh g⁻¹ at 1 C), and excellent capacity retention (80.1 % after 400 cycles at 1 C), taking account of lower structure disorder (Ni²⁺ occupying Li sites is 1.56 %) and integrated grains with an average of 2–3 μm. In addition, the single-crystal material also displays a superior rate capability of 159.1 mAh g⁻¹ at the rate of 5 C. This excellent performance is attributed to the rapid Li⁺ transportation within the crystal structure with fewer Ni²⁺ cations in Li layer as well as intactly single grains. In sum, the regulation of Li⁺/Ni²⁺ mixing provides a feasible strategy for boosting single-crystal nickel-rich cathode material.