Study of the effect of cation substitution on the local structure and the properties of perovskites and Li-ion battery cathode materials
20 oktober 2020
Online - - - - -
Organisatie / co-organisatie:
ONLINE Doctoraatsverdediging Mylène Hendrickx - Faculteit Wetenschappen, Departement Fysica
The type and arrangement of the atoms in a material, called the crystal structure, determine its physical properties. Thus to gain control over materials properties, the first step is to determine these crystal structures. During my PhD, I have investigated the crystal structures of two main groups of materials, perovskites and Li-ion battery cathode materials, to which cation substitution was applied in an attempt to induce and enhance specific properties. For the perovskites, which can have a wide variety of properties depending on small structural changes, we focussed on the magnetic properties, of great importance in nano-electronics. With the Li-ion batteries, we tried to find new cathode materials with enhanced electrochemical performance.
The crystal structures of these new materials were investigated using advanced transmission electron microscopy (TEM) in both reciprocal space (electron diffraction) and direct space (imaging techniques), combined with energy-dispersive X-ray spectroscopy (EDX). Based on these studies, we proposed and refined models for the new structures. With these models, we were able to explain the variations in the properties of these materials. The study of the relation between structure and properties has yielded fundamental knowledge, applicable for the optimization of the properties of the investigated materials as well as of related materials.