The thermal stability and structural changes of well-crystallized Li4Mn5O12 powder with a grain size of 0.1-0.3 μm have been investigated with thermogravimetric analysis (TGA), X-ray diffraction (XRD), and high-temperature X-ray diffraction measurements (HT-XRD). Li4Mn5O12 crystallites are stable at temperatures up to 600°C in oxygen or air, but decompose to spinel LiMn2O4 and monoclinic Li2MnO3 at temperatures between 530 and 680°C, and to LiMnO2 and Mn3O4 at temperatures above 680°C in nitrogen. No apparent structural change was detected with XRD and HT-XRD when Li4Mn5O12 was heated in O2 up to 700°C, but a reversible weight loss/gain due to the evolution/uptake of oxygen was observed by TGA between 400-700°C. The deficiency of oxygen in Li4Mn5O12-δ is found to be in the region 0 < δ ≤ 0.5.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Condensed Matter Physics
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry