Wavelength-dependent neutron transmission of battery components for accurate Rietveld refinement of operando neutron diffraction data from unmodified industry-like pouch cells

This proposal aims to perform wavelength-dependent neutron transmission measurements of individual battery components to enable accurate Rietveld refinement of operando neutron powder diffraction (oNPD) data from industry-like, unmodified multi-layer pouch (MLP) lithium-ion battery cells. Understanding structural degradation during cycling is critical for improving battery longevity and performance. oNPD is particularly suited for such studies due to its sensitivity to lithium, ability to distinguish various transition metal cations, and non-invasiveness. However, traditional studies frequently involve modified cells that do not accurately reflect real operating conditions.
Previous preliminary measurements conducted on the Polaris instrument demonstrated that unmodified MLP cells yield high-quality diffraction patterns. However, accurate Rietveld refinement of neutron diffraction data collected at pulsed sources requires precise absorption corrections to account for wavelength-dependent neutron attenuation.
This proposal aims to utilise the unique capabilities of the Vesuvio spectrometer to obtain the neutron transmission spectra of each battery component. The acquired data will allow precise calculation of wavelength-dependent absorption corrections using the Busing-Levy formula. Corrected diffraction patterns of the components that are not of interest will be subtracted from that of the cell, enabling unprecedented structural analyses of the electrodes during cycling.