Wetting of sodium on β″-Al2O3/YSZ composites for low temperature planar sodium-metal halide batteries

Wetting of Na on β″-Al2O3/YSZ composites was investigated using the sessile drop technique. The effects of moisture and surface preparation were studied at low temperatures. Electrical conductivity of Na/β″-Al2O3-YSZ/Na cells was also investigated at low temperatures and correlated to the wetting behavior. The use of planar β″-Al2O3 substrates at low temperature with low cost polymeric seals is realized due to improved wetting at low temperature and conductivity values consistent with the literature.

► Thin films of Sn at the surface of β″-Al2O3 samples was shown to improve the wetting of Na. ► Wetting was further improved by removing surface water at high temperature under vacuum. ► Complete wetting of Na on the β″-Al2O3 surface was achieved at temperatures as low as 200 °C. ► Electrical conductivity and activation energies were in good agreement with the literature. ► Ability to use low cost polymeric seals to be used at operating temperatures of ≤200 °C is realized.