Abstract :
Spherical particle morphology of Li1.1Ni1/3Co1/3Mn1/3O2 cathode material was carefully controlled by spray drying the slurry containing mixed oxides pre-calcined at 900 °C. The as-dried powders were then treated in a microwave-processing cavity with different power and time. The microwave-processing cavity is a designed elliptically resonant cavity with double foci. One focusing zone concentrated microwave energy to treat the as-dried cathode material. After microwave-treated power of 200 W for 15 min at least, high purity of Rocksalt structure showed high ratio of integrated intensities of (0 0 3)/(1 0 4), larger than 1.1, and double peaks (0 0 6)/(1 0 2) and (1 0 8)/(1 1 0) split up clearly based on X-ray diffraction patterns. After 200 W microwave treating for 15 min, the discharge capacity of the obtained Li1.1Ni1/3Co1/3Mn1/3O2 powders was 120 mAh g−1 by charging from 4.3 to 2.5 V at room temperature. Furthermore, discharge capacity larger than 140 mAh g−1 can be obtained for treating with 200 W microwave energy for 30 min. Nevertheless, the discharge capacity was less than 100 mAh g−1 treated with 1100 °C/24 h by conventional furnace. The microwave-treated Li1.1Ni1/3Co1/3Mn1/3O2 cathode material sustains capacity less than 5% degradation after 50 cycles test. The results of microwave process show promise properties requirement for commercial applications.
