Elevated stability of nickel-rich oxide cathode material with concentration gradient of transition metals via a novel size-controllable calcination method
Elevated stability of nickel-rich oxide cathode material with concentration gradient of transition metals via a novel size-controllable calcination method
Consumers are increasingly demanding the range and safety of the electric vehicles. Nickel-rich layered lithium transition-metal oxide cathode material with Ni content exceeding 80% has attracted extensive attention due to its high capacity. To suppress the decrease of cyclic and thermal stability due to the in-crease of nickel content, LiNi0.87Co0.06Mn0.07O2 particles with transition metal concentration gradient from the interior to the surface are realized. An efficient and low-cost method is proposed involves firstly forming the shell layer with low nickel content by a dry mechanofusion process and subsequently adopting a novel particle size-controllable calcination course. Through which a concentration gradient layer with a thickness of 1 mu m is successfully formed, and the particle size of primary particles is effectively controlled at the range of 250-300 nm. The relationship between the calcination conditions, the morphology, particle size of primary particles and the electrochemical performance have been established. Capacity of 211.9 mAh/g and initial coulomb efficiency of 90.29% have been achieved by LiNi0.87Co0.06Mn0.07O2 with superficial transition metal concentration gradient, and the capacity retention rate at 1 C reached 86.1% after 400 cycles in a pouch cell. In addition, the thermal decomposition temperature is elevated from 220 degrees C to 242 degrees C, the safety of the Ni-rich material has been also effectively improved. (C) 2021 Published by Elsevier B.V.
Key words
Lithium ion battery/Nickel-rich cathode/Core-shell/Gradient/Thermal stability/NI-RICH/ELECTROCHEMICAL PERFORMANCE/ELECTRODE MATERIALS/LITHIUM BATTERIES/LAYERED CATHODES
NSTL
Elsevier