Effect of Calcination Temperature of Size Controlled Microstructure of LiNi0.8Co0.15Al0.05O2 Cathode for Rechargeable Lithium Battery

Size controlled, LiNi0.8Co0.15Al0.05O2 cathode powders were prepared by co-precipitation method followed by heat treatment at temperatures between 750 and 850 degrees C. The synthesized samples are characterized by X-ray diffiaction (XRD), scanning electron microscopy (SEM) and electrochemical performance. The synthesized LiNi0.8Co0.15Al0.05O2 after calcined at 750 degrees C has a good electrochemical performance with an initial discharge capacity of 190 mAh g(-1) and good capacity retention of 100% after 30 cycles at 0.1C (17 mA g(-1)). The capacity retention of LiNi0.8Co0.15Al0.05O2 after calcined at 750 degrees C is better than that at 800 and 850 degrees C without capacity loss at various high C rates. This is ascribed to the minimized cation disorder, a higher conductivity, and higher lithium ion diffusion coefficient (D-Li) observed in this material. In the differential scanning calorimetry DSC profile of the charged sample, the generation of heat by exothermic reaction was decreased by calcined at high temperature, and this decrease is especially at 850 degrees C. This behavior implies that the high temperature calcinations of LiNi0.8Co0.15Al0.05O2 revent phase transitions with the release of oxygen.