Oxygen Separation Technology beyond Conventional Ceramic Ion Transport Membrane Materials – a Perspective

Advances in the field of ion transport membrane (ITM) materials for gas separation and energy conversion are needed to address challenges for more efficient high‐purity oxygen production and cleaner energy source creation. In this framework, electrochemical devices (oxygen generators, catalytic membrane reactors, fuel cells, etc.) based on high‐temperature ceramic ITM are designed to play a critical role in decarbonating the future energy balance. However, the target cost necessitates these electrochemical devices to operate at intermediate temperatures (500–800 °C). To achieve this aim, the oxygen transport of ceramic membranes needs to be increased. It turned out to be difficult to find ceramic oxide materials with lower energy barriers for oxygen ion migration to serve as the intermediate temperature ITMs. Recently, molten oxides with lower activated barriers for oxygen bulk transport and surface exchange kinetics have attracted attention. New molten oxide membranes (MOMs) and diffusion‐bubbling membranes (DBMs) with high oxygen permeability and theoretically infinite selectivity have been developed. This perspective article highlights the recent advances in the field and shows the great potential of the MOMs and DBMs to overcome the limitations of ceramic ITMs.