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Thomas Demuth

Publications and source records attributed to Thomas Demuth.

2 recordsLinked to original sources

LiNiO2/NiO Phase Prediction Using Artificial Neural Networks

In the realm of material analysis, identifying different material phases is of key importance. Artificial intelligence in the form of neural networks provides a very fast and, once trained, computationally inexpensive method for analysing large amounts of image data, like the sets of diffraction patterns generated during four-dimensional scanning transmission electron microscopy (4DSTEM) dataset acquisition. In this work, we train multiple network architectures on images of this type to distinguish between the phases of LiNiO2 and NiO, an important and challenging distinction in the lithium-ion battery community, since the formation of NiO limits battery capacity. We test both classical convolutional neural networks (CNNs) and different forms of vision transformers (ViTs). Our networks are trained on synthetic images and tested on experimentally recorded diffraction patterns. Additionally, we also investigate the decision-making of our networks using the GradCAM method. We test our networks on both synthetic as well as experimental diffraction patterns. Our networks exhibit very robust results, especially when dealing with highly varying data, an area where traditional template-matching methods typically struggle.

cond-mat.mtrl-sci

Determining the grain orientations of battery materials from electron diffraction patterns using convolutional neural networks

Polycrystalline materials have numerous applications due to their unique properties, which are often determined by the grain boundaries. Hence, quantitative characterization of grain as well as interface orientation is essential to optimize these materials, particularly energy materials. Using scanning transmission electron microscopy, matter can be analysed in an extremely fine grid of scan points via electron diffraction patterns at each scan point. By matching the diffraction patterns to a simulated database, the crystal orientation of the material as well as the orientation of the grain boundaries at each scan point can be determined. This pattern matching approach is highly time intensive. Artificial intelligence promises to be a very powerful tool for pattern recognition. In this work, we train convolutional neural networks (CNNs) on dynamically simulated diffraction patterns of LiNiO2, an important cathode-active material for Lithium-ion batteries, to predict the orientation of grains in terms of three Euler angles for the complete fundamental orientation region. Results demonstrate that these networks outperform the conventional pattern matching algorithm with increased accuracy and efficiency. The increased accuracy of the CNN models can be attributed to the fact that these models are trained by data incorporating dynamical effects. This work is the first attempt to apply deep learning for analysis of electron diffraction data and enlightens the great potential of ML to accelerate the analysis of electron microscopy data, toward high-throughput characterization technique.

cond-mat.mtrl-sci