Synthesis and characterization of high-density non-spherical Li(Ni1/3Co1/3Mn1/3)O2 cathode material for lithium ion batteries by two-step drying method

Non-spherical Li(Ni1/3Co1/3Mn1/3)O-2 powders have been synthesized using a two-step drying method with 5% excess LiOH at 800 degrees C for 20 h. The tap-density of the powder obtained is 2.95 g cm(-3). This value is remarkably higher than that of the Li(Ni1/3Co1/3Mn1/3)O-2 powders obtained by other methods, which range from 1.50 g cm(-3) to 2.40 g cm(-3). The precursor and Li(Ni1/3Co1/3Mn1/3)O-2 are characterized by Xray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscope (SEM). XPS studies show that the predominant oxidation states of Ni, Co and Mn in the precursor are 2(+), 3(+) and 4(+), respectively. XRD results show that the Li(Ni1/3Co1/3Mn1/3)O-2 material obtained by the two-step drying method has a well-layered structure with a small amount of cation mixing. SEM confirms that the Li(Ni1/3Co1/3Mn1/3)O-2 particles obtained by this method are uniform. The initial discharge capacity of 167 mAh g(-1) is obtained between 3 V and 4.3 V at a current of 0.2 C rate. The capacity of 159 mAh g(-1) is retained at the end of 30 charge-discharge cycle with a capacity retention of 95%. (C) 2008 Elsevier Ltd. All rights reserved.