UNIST scientists has developed a new composite catalyst to enhance the charge-discharge performances of Metal-Air Batteries (MABs).
The novel catalyst – developed by Professor Guntae Kim and his team – is a very thin layer of metal oxide films deposited on a surface of perovskite catalysts.
The interface which is naturally formed between the two catalysts, helps enhance the overall performance and stability of the new catalyst.
MABs are one of the lightest and most compact types of batteries. They are equipped with anodes made up of pure metals (Lithium, Zinc, Magnesium, and Aluminum) and an air cathode that is connected to an inexhaustible source of air.
Due to their high theoretical energy density, MABs have been considered a strong candidate for the next-gen electric vehicles.
Nevertheless, one major issue hindering their commercialization is that MABs use rare and expensive metal catalysts like platinum for their air electrodes.
Scientists have been suggesting perovskite catalysts as an alternative due to their excellent catalyic performance. They however suffer from low-activation barriers.
Kim and his team have now solved this issue by combining two very different catalysts – each of which showed excellent performance in charge and discharge reactions – to create a new composite catalyst.
The metal catalyst (cobalt oxide), which performs well in charging, is deposited on a very thin layer on top of the manganese-based perovskite catalyst (LSM), which performs well in discharge.
As a result, the synergistic effect of the two catalysts became optimal when the deposition process was repeated 20 times.
“During the repeated deposition and oxidation cycles of atomic layer deposition (ALD) process, the Mn cations diffuse into Co3O4 from LSM, and therefore, the LSM-20-Co catalyst is composed of LSM encapsulated with the self-reconstructedspinel interlayer (Co3O4/MnCo32O4/LSM),” says Arim Seong, first author of the study.
“And this has enhanced the catalytic activitiy of the hybrid catalyst, LSM-20-Co, leading to superior bifunctional electrochemical performances for the ORR and the OER in alkaline solutions.”
“To the best of our knowledge, this is the first study to investigate the self-reconstructed interlayer induced by the in-situ cation diffusion during ALD process for designing an efficient and stable bifunctional catalyst for alkaline zinc-air batteries.”
Image and content: UNIST