Researchers say a new compound could affect fuel cells and make batteries more powerful. It has unique properties that enhance ion flow, opening new opportunities for battery performance.
A battery’s power is reliant on how fast ions pass through the electrolyte. It’s something that engineers, including the researchers of this new study, have been working on for years.
The role of GDC
The team, comprised of engineers and scientists from Clemson University and the University of South California, attempted to solve this problem using gadolinium doped ceria (GDC). It’s a material that contains tiny grains, which ions travel through with ease. But gadolinium typically accumulates at the boundaries of these grains, which in turn slows down the ions.
"The origin of the low grain boundary conductivity is known to be segregation of gadolinium in the grain boundary which leads to a built-in charge at the interface referred to as the space charge effect," said Fanglin Chen, a mechanical engineering professor at the University of South California.
He added: "This built-in charge serves as a barrier for ion transport at the interface. The challenge is how to effectively avoid the segregation of (gadolinium) in the grain boundary. The grain boundary is extremely narrow, on the order of a few nanometers. Therefore, it is extremely difficult to characterize and rationally control the amount of (gadolinium) in such a narrow region."
Using cobalt iron spinel
In an attempt to solve this issue, the researchers summoned cobalt iron spinel (CFO). They discovered the compound eliminated the excess gadolinium from the grain boundaries and cleared the way for ions, simplifying travel through the electrolyte.
"The CFO reacts with the excess (gadolinium) present in the grain boundary of GDC to form a third phase,” said researcher Kyle Brinkman. “It was found that this new phase could also serve as an excellent oxygen ionic conductor. We further investigated the atomic microstructure around the grain boundary through a series of high resolution characterization techniques and found that (gadolinium) segregation in the grain boundary had been eliminated, leading to dramatic improvement in the grain boundary oxygen ionic conductivity of GDC."
Implications for batteries
This discovery has huge implications for batteries and fuel cells. "The ability to control the performance of materials by tuning small interfacial regions represents a huge opportunity in the design of materials for use in energy conversion and storage," said Brinkman.
Brinkman and his team still have a lot of research to accomplish. The compounds they used works at a temperature that is too hot for humans. The researchers are currently looking at other compounds that may do the same thing at cooler temperatures. Still, this discovery is significant and may come in handy for various industries, including the ever-growing electric car market.
Sources: University of South California and Clemson University