This 20nm double perovskite nanofiber can be used as a highly efficient catalyst for ultrafast oxygen evolution reactions. Image: Georgia Tech.
This 20nm double perovskite nanofiber can be used as a highly efficient catalyst for ultrafast oxygen evolution reactions. Image: Georgia Tech.

One of the keys to building electric cars that can travel longer distances and to powering more homes with renewable energy is developing efficient and highly capable energy storage systems. Materials researchers at Georgia Institute of Technology have now created a nanofiber that could help produce the next generation of rechargeable batteries and increase the efficiency of hydrogen production from water electrolysis.

In a paper published in Nature Communications, the researchers describe their development of a double perovskite nanofiber that can be used as a highly efficient catalyst for ultrafast oxygen evolution reactions (OER). This is one of the central 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," explained Meilin Liu, a professor in the Georgia Tech School of Materials Science and Engineering. "The problem is that the batteries lack a cost-efficient catalyst to improve their efficiency. This new catalyst will improve that process."

The new catalytic nanofiber possesses a perovskite crystal structure. "This unique crystal structure and the composition are vital to enabling better activity and durability for the application," Liu said.

The perovskite oxide fiber is fabricated via an electrospinning process, during which the researchers used a technique called composition tuning – or ‘co-doping’ – to improve the intrinsic activity of the catalyst by approximately 4.7 times. The fiber is just 20nm in diameter, which is the thinnest diameter yet reported for electrospun perovskite oxide nanofibers.

The researchers found that the new nanofiber showed markedly enhanced OER capability when compared with existing catalysts. The new nanofiber's mass-normalized catalytic activity was about 72 times greater than the initial powder catalyst, and 2.5 times greater than iridium oxide, which is considered a state of the art catalyst by current standards.

That increase in catalytic activity comes in part from the larger surface area achieved with nanofibers, the researchers said. Synthesizing the perovskite structure into a nanofiber also boosted its intrinsic activity, which improved how efficiently it worked as a catalyst for OER.

"This work not only represents an advancement in the development of highly efficient and durable electrocatalysts for OER but may also provide insight into the effect of nanostructures on the intrinsic OER activity," the researchers wrote.

Beyond its use in the development of rechargeable metal-air batteries, the new catalyst could also lead to more efficient fuel cell technologies that could aid 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."

According to Liu, that's where the new nanofiber catalysts could make a difference. "To store that energy, batteries are still very expensive," he 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."

This story is adapted from material from Georgia Institute of Technology, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.