Imaging Sodium Dendite Growth in all-solid-state sodium batteries


illustration of magnetic field and na electrode with dendrite

Research by the Peter Bruce Group and collaborators at the Materials Department and Nottingham University, as reported in Angewandte Chemie, describes two-dimensional, Knight-shifted, T2-contrasted 23Na magnetic resonance imaging (MRI) of an all-solid state cell with a Na electrode and a ceramic electrolyte 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 microsopcy.  A significantly larger 23Na T2 for the dendritic growth, compared with the bulk metal electrode, is attributed to increased sodium ion mobility in the dendrite.  23NaT2-contrast MRI of metallic sodium offers a clear, routine method for observing and isolating microstructural growth and can supplement the current suite of techniques utilised to analyse dendritic growth in all-solid-state cells.