A novel 3D-printed electrochemical cell for operando synchrotron experiments

Electrochemical processes are often accompanied by significant transformations at the electrode-electrolyte interface, such as the formation of a solid electrolyte interphase or surface reconstruction. Studying these dynamic changes requires operando characterization techniques to overcome the limitations of ex-situ methods. Here, we present a novel, versatile electrochemical cell optimized for operando synchrotron X-ray studies of the lithium-mediated nitrogen reduction reaction. The cell integrates a single-crystal working electrode with a gas diffusion counter electrode, enabling enhanced faradaic efficiencies (FEs) and operando measurements under conditions that closely resemble scalable flow systems. The cell design improves N₂ availability and suppresses undesirable counter electrode reactions through the hydrogen oxidation reaction, achieving FEs of up to 37% for ammonia production. Fabrication by 3D-printing polyether ether ketone allows for complex electrolyte flow geometries while maintaining minimal X-ray background interference, critical for X-ray-based techniques. The combination of single-crystal electrodes and optimized flow conditions offers a promising platform for investigating fundamental electrochemical processes under realistic and scalable conditions.