Preparation and electrochemical performance of ball-like LiMn0.4Ni0.4Co0.2O2 cathode materials

Ball-like LiMn0.4Ni0.4Co0.2O2 particles composed of flakes were synthesized by a simplified co-precipitation method followed by a solid-state reaction at temperatures of 600–900 °C. The relationship between the flake thickness and the electrochemical performance of the layered oxides was investigated in this work. The layered oxide with a flake thickness of 80–100 nm synthesized at 800 °C has the best electrochemical performance among these cathode materials, especially the rate capability. An initial discharge capacity of 160 mAh g−1 was obtained at 5 C (1400 mA g−1) in the voltage range of 2.5–4.5 V, and the capacity retention was 80% after 50 cycles. The excellent rate capability is attributed to the well formed structure, short diffusion distance and good crystallinity. In addition, a detailed study of diffusion coefficient of Li+(DLi+)(DLi+) was carried out to further understand this material. The value of DLi+DLi+ calculated is in the range of 10−11 to 10−12 cm2 s−1.

► Ball-like LiMn0.4Ni0.4Co0.2O2 particles composed of flakes are synthesized. ► Oxide with flake thickness of 80–100 nm has the best electrochemical properties. ► High specific capacity of 160 mAh g−1 can be obtained at 5 C (1400 mA g−1). ► Diffusion coefficient of Li+ of 10−11 to 10−12 cm2 s−1 is obtained by EIS and GITT.