Thin-film Au nucleation layers for anode-free Na-metal batteries via ex-situ GI-PDF/SAXS

One of the challenges to advance so called anode-free Na-batteries is the homogenization of Na-metal deposition. Recently, thin alloy-layers are applied onto the current collector to homogenize Na-deposition through their sodiophilicity. However, the detailed structural evolution of the electrochemically Na-alloyed phases is not understood, as the kinetically driven process might give rise to meta-stable phases and/or amorphous intermediate phases - while the properties of these phases will determine the nucleation barrier and smoothness of Na-plating. To determine the structure-activity relationship, we want to resolve the electrochemically induced alloying between Na and a 100 nm thin Au-alloy layer via ex-situ gracing incidence pair distribution function and small angle X-ray scattering experiments. The Au layer can be considered as a model system and the results are expected to impact the understanding on how to design nucleation functional layers for anode-free Na-metal batteries.