Zhongjun Chen

Synthesis and Characterization of Nonspherical LiCoO2 with High Tap Density by Two-Step Drying Method

Nonspherical LiCoO 2 powders have been synthesized using a two-step drying method. The tap density of the powder obtained is 3.06 g cm -3 , which is remarkably higher than that of spherical LiCoO 2 powders (only 2.40 g cm -3 ). The LiCoO 2 powder is also characterized by X-ray diffraction (XRD) and scanning electron microscopy. The XRD analysis shows that the material has a well-ordered layered structure. Initial charge and discharge capacities of 165 and 152 mAh g -1 are obtained between 3 and 4.2 V at a current of 0.2 C rate. The nonspherical LiCoO 2 cathode material demonstrates a stable cyclability over 50 charge-discharge cycling.

Synthesis and Electrochemical Properties of High-Density LiNi0.8Co0.2O2 for the Lithium-Ion-Battery Cathode

LiNi 0.8 Co 0.2 O 2 powder with a tap density of 3.23 g cm -3 has been successfully prepared by a molten-salt synthesis method using a eutectic molten salt of 0.62LiNO 3 -0.38LiOH with a melting point of 175.7°C and Ni 0.8 Co 0.2 (OH) 2 , where the ratio of Li/(Ni + Co) is controlled at 1.1:1. X-ray diffraction analysis has shown that this material has a well-developed layered structure. Charge-discharge tests have shown that an LiNi 0.8 Co 0.2 O 2 cathode prepared at 800°C has an initial discharge capacity as high as 163 mAh g -1 and excellent capacity retention in the range of 3.0-4.3 V at a current density of 0.2 mA cm -2 .