Effects of synthesis conditions on layered Li[Ni1/3Co1/3Mn1/3]O2 positive-electrode via hydroxide co-precipitation method for lithium-ion batteries

Layered Li[Ni(subscript 1/3)Co(subscript 1/3)Mn(subscript 1/3)]O2 was synthesized with complex metal hydroxide precursors that were prepared by a co-precipitation method. The influence of coordination between ammonia and transition-metal cations on the structural and electrochemical properties of the Li[Ni(subscript 1/3)Co(subscript 1/3)Mn(subscript 1/3)]O2 materials was studied. It is found that when the molar ratio of ammonia to total transition-metal cations is 2.7:1, uniform particle size distribution of the complex metal hydroxide is observed via scanning electron microscopy. The average particle size of Li[Ni(subscript 1/3)Co(subscript 1/3)Mn(subscript 1/3)3]O2 materials was measured to be about 500 nm, and the tap-density was measured to be approximately 2.37 g/cm^3, which is comparable with that of commercialized LiCoO2. XRD analysis indicates that the presently synthesized Li[Ni(subscript 1/3)Co(subscript 1/3)Mn(subscript 1/3)]O2 has a hexagonal layered-structure. The initial discharge capacity of the Li[Ni(subscript 1/3)Co(subscript 1/3)Mn(subscript 1/3)]O2 positive-electrode material is determined to be 181.5 mA•h/g using a Li/Li[Ni(subscript 1/3)Co(subscript 1/3)Mn(subscript 1/3)]O2 cell operated at 0.1C in the voltage range of 2.8-4.5 V. The discharge capacity at the 50th cycle at 0.5C is 170.6 mA•h/g.