Oxygen Exchange Across the Melting Point of V₂O₅–Advancing Beyond Solids?

Abstract Oxide melts have the potential to enhance the performance and reduce operating temperature in sustainable chemical and electrochemical technologies by improving the kinetics of the oxygen reduction reaction and oxide ion transport. This study provides the first in situ investigation of the effects of the solid‐liquid phase transition on the rate of oxygen exchange for V 2 O 5 , both as single‐phase material and as a component in a ZrV 2 O 7 ‐30mol%V 2 O 5 composite. Upon melting of the V 2 O 5 phase, the rate coefficients for both surface and bulk oxygen kinetics increase several orders of magnitude. The rate‐determining step of the oxygen exchange reaction shifts from incorporation to dissociative adsorption. Oxygen kinetics of molten V 2 O 5 matches, and in some cases surpasses state‐of‐the‐art solid‐state oxide‐based materials. Although liquid oxide‐based components may offer enhanced performance and efficiency, addressing challenges related to chemical and mechanical stability is required before application in next‐generation electrochemical cells and oxygen transport membranes can be viable.