▲ Schematic diagram of the development of high-efficiency electrolyte catalyst technology for lithium-air batteries using eco-friendly porphyrin-based electrolyte catalysts (Image provided by Professor Won-Hee Ryu, Sookmyung Women's University)



Energy density 2–3 times higher than lithium batteries
Capable of long-distance driving of over 500km

The National Research Foundation of Korea has developed a lithium-air battery technology using porphyrin-based metal phthalocyanine, a naturally extracted material, presenting a new research direction for next-generation battery technology.

The National Research Foundation of Korea announced that a joint research team led by Professor Ryu Won-hee of Sookmyung Women's University and Professor Kim Jong-soon of Sungkyunkwan University has developed a porphyrin-based catalyst system for lithium-air batteries capable of active oxygen bonding.

Porphyrin metal phthalocyanines are compounds in which a metal atom is located at the center of a square macro-ring composed of carbon and nitrogen, and are known to actively bind with oxygen.

As regulations on greenhouse gas emissions accelerate to address environmental issues such as global warming, existing gasoline cars are being replaced by electric vehicles.

For commercial electric vehicles based on lithium-ion batteries, the driving range is approximately 200 to 300 km, making it difficult to travel from Seoul to Busan on a single charge.

Currently, the short driving range of electric vehicles necessitates frequent charging, and various limitations apply to the popularization of electric vehicles due to long charging times and anxiety about battery discharge. there is.

Lithium-air batteries have an energy density 2 to 3 times higher than that of lithium-ion secondary batteries, and are expected to enable long-distance driving of over 500 km.

Currently, it is being pointed out that lithium-air batteries experience significant resistance due to insulating byproducts during operation, which leads to a substantial reduction in battery lifespan.

To improve the performance of lithium-air batteries, the introduction of high-efficiency catalysts is necessary, and making catalysts eco-friendly and low-cost is essential for the popularization of commercial electric vehicles.

Based on the active oxygen binding properties of porphyrins readily found in nature, such as chlorophyll and hemoglobin, the research team succeeded in significantly improving efficiency by introducing metal phthalocyanine, a well-known porphyrin-based material, as an electrolyte catalyst for lithium-air batteries.

By varying the type of metal located at the center of each phthalocyanine, differences in electrochemical redox reactions were identified, and the type of center metal with optimal performance was determined.

A redox reaction is a chemical reaction in which the oxidation number of an atom changes as an oxidation reaction, which donates electrons, and a reduction reaction, which accepts electrons, occur during the reaction process.

By mixing the highest-performing manganese phthalocyanine and zinc phthalocyanine materials, an electrolyte catalyst effective for both oxygen reduction and oxygen evolution reactions was developed.

The mixed catalyst exhibited high capacity and stable lifespan characteristics even under actual atmospheric conditions where the oxygen fraction was 20% or less.

Professor Ryu Won-hee stated, “Lithium-air batteries are attracting attention as a next-generation breakthrough battery technology as ultra-high-energy secondary batteries,” adding, “Through the results of this research, we have secured core source technology that can significantly improve the performance of lithium-air batteries.”

Meanwhile, the basic research project promoted by the Ministry of Science and ICT and the National Research Foundation of Korea (Outstanding Young ResearcherThis research achievement, carried out with support from the National Core Materials Research Group (Specialized Type) and the Leading Research Center, was published as a cover article in the international journal 'Advanced Energy Materials' on February 17.