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Caption: A tailored double perovskite nanofiber catalyst enables ultrafast oxygen evolution. Credit: The Georgia Institute of Technology

A new nanofiber could enable the next generation of rechargeable batteries, enhancing the batteries used in electric cars.

Material researchers at the Georgia Institute of Technology have created a double perovskite nanofiber that can be used as a highly efficient catalyst in ultrafast oxygen evolution reactions—one of the underlying electrochemical processes in hydrogen-based energy and the newer metal-air batteries.

“Metal-air batteries, such as those that could power electric vehicles in the future, are able to store a lot of energy in a much smaller space than current batteries,” Meilin Liu, a regents professor in the Georgia Tech School of Materials Science and Engineering, said in a statement. “The problem is that the batteries lack a cost-efficient catalyst to improve their efficiency. This new catalyst will improve that process.”

One of the unique parts of the development is the perovskite—the crystal structure of the catalyst used to form the nanofibers.

Liu explained that the catalyst will lower the cost needed to make batteries.

“To store that energy, batteries are still very expensive,” Liu said. “We need a good catalyst in order for the water electrolysis to be efficient. This catalyst can speed up electrochemical reactions in water splitting or metal air batteries.”

The researchers used a technique called composition tuning or co-doping during the synthetization process to improve the intrinsic activity of the catalyst by approximately 4.7 times. The perovskite oxide fiber made during the electrospinning process was about 20 nanometers in diameter—which would make it the thinnest diameter reported for electrospun perovskite oxide nanofibers.

The researchers found that the new substance revealed markedly enhanced oxygen evolution reaction capability when compared to existing catalysts. The new nanofiber’s mass-normalized catalytic activity improved about 72 times greater than the initial powder catalyst and 2.5 times greater than iridium oxide, which is considered the best catalyst by current standards.

That increase in catalytic activity comes in part due to a larger surface area achieved with nanofibers. Synthesizing the perovskite structure into a nanofiber also boosted its intrinsic activity, improving how efficiently it works as a catalyst for oxygen evolution reactions.

According to the study, the oxygen evolution reaction is an essential but sluggish step in many energy storage and conversion processes and has received significant attention, particularly in the development of solar/electricity-driven water splitting and rechargeable metal–air batteries.

Beyond its applicability in the development of rechargeable metal air batteries, the new catalyst could also represent the next step in creating more efficient fuel cell technologies, aiding in the creation of renewable energy systems.

“Solar, wind, geothermal—those are becoming very inexpensive today. But the trouble is those renewable energies are intermittent in nature,” Liu said. “When there is no wind, you have no power.

“But what if we could store the energy from the sun or the wind when there's an excess supply. We can use that extra electricity to produce hydrogen and store that energy for use when we need it.”

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