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

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.