Abstract: Spherical Ni_0.8Co_0.1Mn_0.1(OH)₂ precursors with a high tap-density and a narrow size-distribution were synthesized via coprecipitation using NaOH and NH₃·H₂O as the precipitation and complexing agents. Spherical LiNi_0.8Co_0.1Mn_0.1O₂ particles were then prepared by sintering the mixture of this precursor and LiOH·H₂O. The prepared materials were characterized by XRD, SEM, TEM, TGA/DSC and galvanostatically charge/discharge tests. The results indicate that secondary spherulites of the precursors are formed by aggregation of crystals but not by elongated crystals. The reaction time shows a significant effect on the morphology, size-distribution and tap-density of the precursor. The LiNi_0.8Co_0.1Mn_0.1O₂ powders calcined under 750℃ for 16 h exhibit a spherical morphology with the highest tap-density (2.98 g/cm³) and the largest initial discharge capacity (202.4 mAh/g). More than 92.3% of the capacity is retained after 40 cycles. In addition, the cell delivers a discharge capacity of 174.1 mAh/g at 3C rate.

Key words: spherical particle, coprecipitation, LiNi_0.8Co_0.1Mn_0.1O₂, Li-ion batteries