Operando mapping of morphology, phase transformations, and current patterns in energy devices by advanced neutron imaging and diffraction

by Prof. Luise Theil Kuhn (DTU Energy, Technical University of Denmark)

Monday 8 Jun 2026, 14:30 → 15:30 Europe/Berlin

PH HS 3 (Physics Department)

A core activity in the ESS Lighthouse Hard Materials in 3D, SOLID (https://solid.dtu.dk/), has been to develop advanced neutron imaging methods for operando analysis of microstructure, phase transformations, and current patterns in energy devices. Here, I will present two cases where we have investigated the battery cell degradation of Na-ion batteries while being charged and discharged, and the current pattern formation in a proton exchange membrane water electrolysis (PEMWE) cell under operation.
Na-ion batteries are one of the promising next-generation battery technologies since they can deliver a capacity comparable to Li-ion batteries while constituting cheap, non-flammable, and sustainable materials. However, the chemical and mechanical stability during cycling is a challenge. The Na-ion battery is inherently difficult to directly image as Na has a very low X-ray and neutron scattering cross-section and can’t sustain post-mortem disassembly and analysis. At the SENJU beamline at J-PARC, we have successfully performed the first multimodal operando neutron studies combining time-of-flight diffraction and Bragg edge imaging to investigate the microstructural changes and phase transformations of the battery electrodes and link them to the electrochemically active regions.
PEMWE cells are considered one of the key technologies for sustainable hydrogen production. PEMWE can be operated under relatively flexible conditions, making them ideal for varying electricity production by e.g. wind turbines or solar cells. A central component is the porous transport layer (PTL), which is used for managing the distribution of water and release of produced gases. The PTL is subject to a very harsh environment and is often based on Ti coated with Pt or Ir. The morphology of the PTL is crucial for the performance of the PEMWE since this is directly linked to the oxygen bubble formation and the current pattern formation in the cell. At the RADEN beamline at J-PARC and NeXT at ILL, we have performed the first polarized neutron imaging studies of the current pattern formation in the PEMWE cell under operation while linking it to the electrochemical performance with different types of PTLs.
Neutron flux is the main limitation in operando neutron imaging, and I’ll finish by presenting our first steps towards overcoming this by implementing a real neutron microscope with a condenser based on Wolter optics and a Fresnel zone plate-based objective.