Mixed-up metals for chemical-looping combustion

Research Project, 2021 – 2024

High-Entropy Oxides for Chemical-Looping Applications

This project investigated high-entropy oxides (HEOs) as oxygen-carrying materials for chemical-looping (CLC), with the aim of identifying new materials with improved reactivity and stability. Due to the vast compositional space of multicomponent oxides, the project combined computational materials science, machine learning, and experimental studies to accelerate materials discovery and improve the understanding of oxygen-carrier behavior.

A major outcome of the project was the development of machine-learning methods for exploring large compositional spaces and identifying promising HEOs. By combining generative models with active learning, several previously unexplored oxygen-carrying materials were identified, creating a portfolio of new candidate materials for CLC. Some of these materials were successfully synthesized and experimentally evaluated.

The project also provided experimental evidence that HEOs can form homogeneous crystalline phases with uniform elemental distributions while exhibiting oxygen-transfer properties comparable to established oxygen carriers. These results demonstrate the potential of HEOs as a platform for future oxygen-carrier development.

In parallel, new methodologies were developed to describe the thermodynamic properties of complex oxide systems. Using first-principles calculations, the project investigated phase stability and oxygen-vacancy formation in manganese-based perovskites, providing new insights into the factors governing oxygen-carrier performance under CLC conditions.

The project further examined interactions between oxygen carriers and ash components originating from biomass and waste-derived fuels. These studies improved the understanding of material stability, reactivity, and degradation mechanisms under realistic operating conditions.

Together, the project generated new methodologies for materials discovery and design, while contributing fundamental knowledge that supports the development of more robust oxygen carriers for CLC technologies and sustainable energy systems.