scientists discover iron-made crystal that can absorb, release, and breathe oxygen

Researchers develop iron-made crystal that breathes oxygen

Scientists from Pusan National University and Hokkaido University create an iron-made crystal material that can absorb, release, and breathe oxygen. Using a metal oxide composition containing strontium, iron, and cobalt, the chemical formula allows the material to perform oxygen exchange cycles without structural damage. 

The oxygen release process happens when researchers heat the crystal in controlled gas environments. The iron-made crystal expels oxygen atoms from its structure during this heating phase, and when conditions change, it absorbs oxygen atoms back into its structure. This cycle can repeat multiple times without degrading the crystal.

metal oxide composition that works at lower temperatures

The reversible process keeps the iron-made crystal that breathes oxygen intact throughout the cycles and processes. This is a breakthrough because the scientists from the two universities state previous materials that performed similar functions often broke down after limited cycles. With their discovery, the material operates at lower temperatures than existing oxygen-controlling materials. Most current materials need extremely high temperatures for oxygen exchange, but with the new crystal, it works at lower temperatures than other materials.

The process affects only cobalt ions within the crystal structure, while the other metal ions remain unchanged during oxygen release and absorption cycles. It is this ‘selective’ behavior that creates a stable crystal formation, making the researcher’s material different from the original structure. When oxygen returns to the system, the crystal reverts to its initial form, proving that the process works in both directions without permanent changes.

Scientists test the material in smart windows

The research team has already tested the iron-made crystal that can breathe oxygen in smart windows. They’ve found out that the material changes transparency based on its oxygen content, with the oxygen-rich version appearing less transparent while the oxygen-depleted version showing increased transparency. Fuel cell applications represent a major potential use for this material, too. The solid oxide fuel cells convert hydrogen into electricity with minimal emissions, and the new crystal could improve fuel cell efficiency and durability.

The material works through controlled chemical reactions. Heating removes oxygen atoms from specific crystal positions, and cooling or changing gas composition allows oxygen atoms to return to these positions. The scientists also see applying the iron-made crystal that can breathe oxygen to electronic applications, which could include oxygen sensors and gas separation systems. So far, the research continues to improve the crystal composition and processing methods, as the team investigates variations in metal ratios to enhance performance. Their future research also attempts to explore additional applications and improve material performance for specific uses.

project info:

name: Selective reduction in epitaxial SrFe0.5Co0.5O2.5 and its reversibility

scientists: Joonhyuk Lee, Yu-Seong Seo, Krishna Chaitanya Pitike, Gowoon Kim, Sangkyun Ryu, Hyeyun Chung, Su Ryang Park, Sangmoon Yoon, Younghak Kim, Valentino R. Cooper, Hiromichi Ohta, Jinhyung Cho, Hyoungjeen Jeen

institutions: Pusan National University, Hokkaido University | @pusan.ac.kr, @hokkaidouni

study: here