A team of scientists from Korea and Japan has discovered a new type of crystal that can "breathe"—releasing and absorbing oxygen repeatedly at relatively low temperatures. This unique ability could transform the way we develop clean energy technologies, including fuel cells, energy-saving windows, and smart thermal devices. The newly developed material is a special kind of metal oxide made of strontium, iron, and cobalt. What makes it extraordinary is that it can release oxygen when heated in a simple gas environment and then take it back in, all without falling apart. This process can be repeated many times, making it ideal for real-world applications.

Controlling oxygen in materials is crucial for technologies like solid oxide fuel cells, which produce electricity from hydrogen with minimal emissions. It also plays a role in thermal transistors—devices that can direct heat like electrical switches—and in smart windows that adjust their heat flow depending on the weather.

Until now, most materials that could do this kind of oxygen control were too fragile or operated only at the harsh conditions like extremely high temperatures. This new material works under milder conditions and remains stable. The team also showed that the material could return to its original form when oxygen was reintroduced, proving the process is fully reversible. 

- Authors (Pusan National University): Joonhyuk Lee, Hyoungjeen Jeen (Department of Physics)

- Title of original paper: Selective reduction in epitaxial SrFe_0.5Co_0.5O_2.5 and its reversibility

- Journal: Nature Communications

- Web link: https://www.nature.com/articles/s41467-025-62612-1 

- Contact e-mail: hjeen@pusan.ac.kr