Two-dimensional, Knight-shifted, T 2-contrasted 23Na magnetic resonance imaging (MRI) of an all-solid-state cell with a Na electrode and a ceramic electrolyte is employed to directly observe Na microstructural growth. A spalling dendritic morphology is observed and confirmed by more conventional post-mortem analysis; X-ray tomography and scanning electron microscopy. A significantly larger 23Na T 2 for the dendritic growth, compared with the bulk metal electrode, is attributed to increased sodium ion mobility in the dendrite. 23Na T 2-contrast MRI of metallic sodium offers a clear, routine method for observing and isolating microstructural growths and can supplement the current suite of techniques utilised to analyse dendritic growth in all-solid-state cells.
Knight‐shift T 2‐weighted MRI measurements of dendrite formation in all‐solid‐state batteries show direct contrast between the bulk electrode and the dendrite formation. This significantly increased T 2 of the spalling dendrite formation is attributed to a local motion of the metallic Na ions.
Keywords: NMR spectroscopy; all-solid-state electrolytes; batteries; magnetic resonance imaging; sodium.
© 2020 The Authors. Angewandte Chemie published by Wiley-VCH GmbH.