Operando Neutron Diffraction Study of High-voltage Structural Degradation Pathways in Industry-like Single-layer Pouch Cells

Understanding degradation in Li-ion batteries is key to devising measures to mitigate it. Over prolonged cycling, irreversible changes happen in the electrodes, leading to eventual capacity fade. Such processes occur across different structural and time scales and can vary depending on the cell configuration and cycling conditions. To encapsulate all of this, operando studies become a useful tool. However, to investigate these effects accurately and reliably, one must use cell designs and cycling conditions as close to real-world conditions as reasonably possible. Currently, the bulk of the operando research into LIB degradation is performed using modified cells. Most of these cells can neither be operated in standard experimental conditions nor be cycled for long durations, making it difficult to reasonably extrapolate results from these experiments to real-world battery operation. Therefore, unmodified cells with reliable long-term cycling must be used for operando studies if a practically useful understanding of their degradation mechanisms is to be obtained. In this study, we aim to perform a first proof of concept operando neutron diffraction study of a single-layer NMC811-graphite pouch cell on WISH. Preliminary tests of a single-layer pouch cell on WISH have provided promising results, and this experiment will help us take the work to the next stage.