Scattering-based structural studies of functional materials: with a focus on structural disorder in battery electrodes

Studies of material structures and their relations to the material properties areat the very heart of materials science. The same is true for electrode materialsfor rechargeable batteries. Being at the doorstep of a green transition, development of novel electrode materials for rechargeable batteries is absolute key.Earlier in time, high crystallinity, i.e. a well-ordered atomic level structure, wasthought of as a prerequisite for electrode materials for intercalation-type batteries like the Li-ion battery technology. Well-ordered crystalline materials can bestudied through powder diffraction techniques combined with Rietveld analysis. However, in more recent years, it has been realized that structural disordermight not necessarily be a poor thing for electrode materials for rechargeablebatteries. However, structural disorder is often associated with loss of diffraction signal and other tools are needed to investigate the atomic level structures of these disordered materials. Total scattering techniques combined with pairdistribution function analysis offer insights to the atomic level structure of otherwise disordered materials. As structural disorder in battery electrodes is afocus of this work, pair distribution function analysis is a key technique andis used to study TiO2-bronze nanocrystals and nanocrystalline TiO2-rutile aselectrodes for Li-ion batteries, just as the technique is used to study disorder ofiron hydroxide phosphate hydrate as Na-ion battery electrode. However, pairdistribution function analysis is not only relevant to study disorder in batterymaterials. In this work, the technique is also used to study iridium oxide materials for the oxygen-evolution reaction in polymer membrane electrolyzer cells.

As data and computer science aspects have become more and more importantduring the PhD program, examples and considerations on this are also providedin this work. This includes both data processing and analysis, just as a prototypeprogram for machine-readable literature and data-driven literature search ispresented.

All the work presented herein in centered around structural studies of functional materials.