Andreas Rosnes' project

Combinatorial study of exsolution nanoparticles for energy conversion and storage technologies

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Figure: (Left) Metal nanoparticles are conventionally prepared directly on the surface of an oxide material in the application of electrode in electrochemical devices, and their tendencies to agglomerate over time limits their performance. (Right) During exsolution, such nanoparticles are grown directly from the oxide material and result in anchored nanoparticles at the surface which hinders agglomeration. Perovskites, which are a material type with three elements in the ratio ABO3, are frequently used as supporting substrate. Defects in the structure can be introduced to facilitate for exsolution, such as A-site deficiency.

If one collects all the solar irradiation flowing towards the Earth in one hour, one will have enough energy to meet the world's consumption in one year. Practically, however, one is dependent on efficient energy storage options, to compensate for daily and seasonal variation in solar irradiation. The same goes for other renewable energy sources such as wind power. 

Exsolution is a growth phenomenon where metal nanoparticles segregate from an oxide material but remain embedded at the surface. The anchored nature of the nanoparticles prevents agglomeration and is one of the reasons why such nanoparticles are observed to have increased performance as electrodes.  

Most exsolution studies so far convey empirical knowledge of individual material systems, and there are many unresolved questions on the exact underlying mechanisms involved in exsolution. The main objective of the project is to find generic principles of the exsolution process which are transferable across different materials systems. In collaboration with the Solaris initiative at UiO: Energy and Environment, a combinatorial synthesis route using pulsed laser deposition (PLD) is applied together with high-throughput characterization methods to explore a large parameter space of material compositions. Choice of parameter space builds upon insight from atomistic simulations of the energy landscape of the majority of defects in the material, in addition to the composition's technological relevance. The project collaborates with the Electrochemistry group for efficiently applying the new insight to device development for an electrochemical cell.  

Methods: 

  • Synthesis: Combinatorial pulsed laser deposition 

  • Characterization: Scanning electron microscopy, x-ray diffraction, transmission electron microscopy, atomic force microscopy, thermogravimetry  

  • Analyses: Automated analyzes of hyperspectral and large (> GB) datasets 

  • Modeling: Density functional theory  

By Andreas Rosnes
Published May 13, 2024 12:50 PM - Last modified May 27, 2024 3:28 PM