Highly defective LiFePO4 powders were synthesized via a modified version of the coprecipitation in aqueous medium method using oxidizing experimental conditions. The nature of the native defects and their influence on the crystallographic structure and on the electrochemical reaction mechanisms were thoroughly studied by a combination of ex situ and in situ methods, using high-resolution transmission electron microscopy, inductive coupled plasma, X-ray diffraction, and Mössbauer spectroscopy. The high concentration of defects induced a unit-cell volume 4 Å**3 smaller than that of stoichiometric LiFePO4, with a complete cationic redistribution over the M1 and M2 crystallographic sites, as well as a completely new electrochemical signature.
COBISS.SI-ID: 5728026
The solvothermal synthesis of ZnO particles from zinc acetylacetonate in the presence of triethanolamine (TEA) and various solvent systems at 170 °C is reported. The structural, optical and morphological characteristics of ZnO particles were investigated. It was found that the size and shape of ZnO nanoparticles and the way of their aggregation depend on the mole ratio TEA/Zn acetylacetonate and the type of alcohol used as a solvent. The results of present investigation show a strong impact of surface interactions between the formed ZnO nanoparticles and the molecules of solvent and TEA on the way of growth and aggregation, which enables the control of their morphological properties. The red shift of the absorption edge and reduced band gap energies are clearly visible with the increased sample microsphere size.
COBISS.SI-ID: 5762330