Computational investigation of interfacial phenomena and catalytic activity in energy materials

Abstract

In the last few decades, tremendous efforts have been made in the development of devices for renewable energy storage and conversion. Energy devices such as Li-ion batteries and fuel cells have almost reached their limits in terms of ionic conductivity or catalytic activity. Therefore, searching for new energy materials with desired properties is the key approach to improving the performance of energy devices. Computational techniques are widely used to predict key properties and provide a fundamental understanding of new materials. In this thesis, two types of energy materials were investigated for different applications: a) a garnet-type solid-state electrolyte for large-scale batteries and b) perovskites with exsolved nanoparticles for electrochemical catalysis.

For garnet-type solid-state batteries, the high interfacial resistance at the anode side is the major challenge for their practical application. Applying an artificial interlayer is an effective approach to reduce the high interfacial resistance at the anode side. Based on density functional theory calculations, we investigated the lithium wettability at different anode/coating interfaces. Metal oxides show a promising ability to enhance lithium wettability. The wettability can be tuned through the lithium contents in the oxides. Besides, we also applied a high throughput screening framework to search for coating candidates from the Materials Project database. A total of 10 lithium-containing ternary oxides are proposed as anode coating candidates for garnet-type solid-state batteries.
For electrocatalytic applications, the exsolution of B-site dopants in CaTiO₃ was investigated. The presence of A-site deficiency coupled with oxygen vacancies can strengthen the segregation energies. The reaction mechanism for CO₂ reduction and CO oxidation over different perovskite surfaces were also studied. For CO₂ reduction, the exsolved bi-metallic nanoparticles on the CaTiO₃ surface exhibit improved catalytic performance. For CO oxidation, the presence of Pt nanoparticles on the LaₓSr₁₋ₓTiO₃ surface can also enhance the CO adsorption.

Date of Award	14 Jun 2023
Original language	English
Awarding Institution	University of St Andrews
Supervisor	John Irvine (Supervisor), Michael Buehl (Supervisor) & Herbert Fruchtl (Supervisor)