LiAlyCo1-yO2 powders were synthesized at 800°C using acrylic acid as a chelating agent. The comparison between local structure refinement of LiCoO2 and LiAl0.25Co0.75O2 during the charging and cycling process was carried out by Co K-edge X-ray absorption spectroscopy (XAS). Al addition was found to cause a larger local structure distortion during Li deintercalation compared to that of LiCoO2. Extended X-ray absorption fine structure refinements during Li deintercalation showed that the degree of structural disorder around Co atoms in LiAl0.25Co0.75O2 becomes higher than that of LiCoO2. XAS analysis for LiCoO2 and LiAl0.25Co0.75O2 during cycling revealed that the large capacity fading of the LiAl0.25Co0.75O2 electrode could be explained by the remaining Co4+ ions and local structure distortion.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry