Researchers at the Ulsan National Institute of Science and Technology (UNIST) in South Korea have devised a novel catalyst for use in metal-air batteries. The findings, which were published in the October issue of the ACS Nano journal, bring us a step closer to commercialization of rechargeable metal-air batteries, which are said to have a power density close to that of gasoline fuel per kilogram.
A metal-air battery is a type of battery cell that utilizes a pure metal anode and an air cathode. The oxygen in the air causes oxidation at the metal cathode and produces electricity. At present, metal-air batteries are expensive due to their use of expensive metals such as platinum or iridium oxide.
The research team at UNIST has shown that the cost of manufacturing these batteries can be reduced significantly by use of a catalyst that uses the cation-ordered double perovskite with high electrical conductivity and catalytic performance. In short, substituting perovskite oxides into the electrode or the catalyst electrode can lead to greater efficiencies due to its high oxygen kinetics, electrical conductivity, oxygen capacity and structural stability.
However, despite all the great benefits of using perovskite oxides in this manner, the high temperatures required for the manufacture of perovskite leads to an increase in particle size, which in turn results in a decrease in surface area. As the oxidation reactions are dependent on the surface area, this is undesirable. To combat this, the researchers manufactured mesoporous samples of the perovskites via an electrospinning process. The introduction of pores into the surface of the perovskite had the effect of also increasing the surface area of the nanofiber structures. The well-controlled B-site metal ratio and large surface area (∼20 m2 g–1) of the mesoporous nanofiber result in high performance of the oxygen reduction reaction and oxygen evolution reaction and stability in the zinc-air battery.
“The structure of mesoporous PrBa0.5Sr0.5Co2-xFexO5+δ nanofiber has high surface areas, result from uniform pore diameters,” said OhhunGwon, the first author of the study. “This nanofiber has also brought significant improvements in the performance of the oxygen reduction reaction and oxygen evolution reaction.”
Industry has big hopes for these metal-air batteries, and research in this field has attracted plenty of funding from big names in industry including IBM and Samsung.
You can find out more about the research in the journal at the following link.