Unveiling the particle-feature influence of lithium nickel manganese cobalt oxide on the high-rate performances of practical lithium-ion batteries

The commercialized lithium nickel manganese cobalt oxides have been extensively applied for high-rate lithium-ion batteries due to its collective merits of fast kinetics, high specific capacity, and reasonable cost. The optimization on lithium nickel manganese cobalt oxide particles is crucial for high-rate batteries since the rate capability, storage and cycling stability are highly dependent on the chemical and physical properties of the cathode materials. Herein, the particle-feature influence on the high-rate performances is investigated to unveil the structure-property relationship. Through systematic electrochemical analysis and material characterizations, a direct comparison among commercial lithium nickel manganese cobalt oxide cathode materials with different particle size, doping, and crystalline structures has been performed. It is found that for polycrystalline lithium nickel manganese cobalt oxide materials, appropriate Al and Zr doping and small particle size are beneficial to superior rate performance and cycling stability up to 30 C. While single-crystalline particles show outstanding storage properties compared to polycrystalline particles with similar size and ion doping. Morphological and structural evolution of the lithium nickel manganese cobalt oxide particles after cycling has been revealed including the changed mixing degree of Li⁺/Ni²⁺, collapsing of primary particles and different parasitic reactions between the electrolyte and the particle surface. This work can provide direct guidance for the subtle design of efficient cathodes for high-rate lithium-ion batteries.