Modeling Of Earth Abundant Oxide Nanoparticles To Guide Materials Design For Energy Applications

Complex materials are vital in our transition to a sustainable energy future playing a key role in a variety of applications including catalysis and batteries. Transition metal oxides belong to this complex class of materials and can be synthesized in a variety of unique ways leading to distinct properties. Understanding why changes in structure lead to changes in a material’s performance, is important to help improve materials design as the need for new energy solutions is urgently needed. Research is focused on using materials with earth abundant metal components, to have the materials design done sustainably and economically. Cobalt oxide is a versatile material that is used in a wide range of applications such as electrocatalysis and Li-ion batteries. The goal is to further improve its performances through different design techniques, such as nanostructuring and doping. Here, density functional theory (DFT) is used to study well-defined, but complex, nanoparticle structures to understand their performance and guide the design, of new and improved materials. This thesis focuses on DFT modeling of nanostructured and doped cobalt oxide based materials as electrocatalysts for the oxygen evolution reaction (OER) and as cathode materials for Li-ion batteries. The computational predictions and findings ofthis thesis provide a fundamental understanding of and the link between the structure and performance of the material at the atomic scale which cannot be achieved by experiment alone. For the OER nanostructured supported Fe-doped cobalt oxide electrocatalyst materials, a computational framework is established and it is identified that a site-specific understanding of the activity is needed to explain the experimentally observed activity trends as well as provide insights for improved materials designs. For the Li-ion cathode material, a similar framework as for the OER elecrocatalysts is used to study the electrochemistry of doped LiCoO2. The role of the dopants on the performance of the battery is examined as well as how the doped structures may change the cathode electrolyte interface. This thesis demonstrates the importance of modeling the details of complex nanostructured electrochemical systems and their interfaces and concludes that site-specific understanding of materials is necessary to explain observable experimental trends and predict new chemistries not accessible by current experimental techniques.