Thursday, 1 June 2017: 10:48
Grand Salon C - Section 13 (Hilton New Orleans Riverside)
Ti doped LiNi0.7Co0.3O2 materials were investigated for their electrochemical characteristics. LiNi0.7Co0.3O2 and LiNi0.6Co0.3Ti0.1O2 materials were prepared using a self-propagating combustion method. The structure and morphology of the materials were characterized using X-Ray Diiffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-Ray Spectroscopy (EDX). The oxidation state of elements and their chemical environments were studied using X-Ray Photoelectron Spectroscopy (XPS). XRD results showed that the materials were all single phase with hexagonal layered structure of R-3m space group. The discharge capacities are between 135.5 and 151.1 mAhg-1. The LiNi0.7Co0.3O2 compound exhibits the highest first cycle capacity of 151.1 mAhg-1 over the voltage range of 2.5 to 4.2 V compared to the Ti doped sample LiNi0.6Co0.3Ti0.1O2, showing a capacity of 146 mAhg-1. However, at the 30th cycle, the Ti doped material shows the highest specific discharge capacity of 137.8 mAhg-1. The capacity fading is only about 5.6 % compared to 38.2% for undoped LiNi0.7Co0.3O2. Therefore, eventhough the undoped LiNi0.7Co0.3O2 material has a higher first cycle capacity, the doped compounds exhibits much better capacity retention over 30 cycles