Ellen Phiddian
Cosmos science journalist
Researchers have developed an X-ray scan (of a sort) for flow batteries that will make them more efficient.
The international team of scientists has published the technique in Nature Communications.
Flow batteries use liquid electrolytes and are safer and longer-lasting than lithium-ion batteries, and could be particularly useful for grid storage.
“To date, the system has remained as a black box,” says senior author Associate Professor Antoni Forner-Cuenca, a researcher at Eindhoven University of Technology, Netherlands.
“The ability to look inside a working battery and visualize concentration distributions would enormously improve our understanding of the system.”
The fluid nature of flow batteries allowed Forner-Cuenca and colleagues to think of a possible imaging technique.
“Our bodies are also mostly composed of fluids, namely water. X-rays pass through that and interact with heavier elements in your bones, allowing you to see them without cutting open a body,” he says.
“Neutrons work the opposite way: they pass through the battery casing materials easily but interact strongly with the molecules in the liquid electrolytes.”
The researchers used neutron radiography to see inside flow batteries.
Credit: Eindhoven University of Technology
“Using this fundamental property of neutrons interacting with certain molecules, we are using neutron radiography for the first time to look at concentrations of molecules in flow batteries,” says Forner-Cuenca.
But, since they wanted to see the movement of molecules, the researchers needed to take a lot of images.
“To track in real time how the concentration of liquids changes in the battery, we continuously take pictures every 30 seconds of the collection of neutrons that travels through the battery,” says Forner-Cuenca.
“We piece those pictures together, so to speak, providing us with a video that shows how the concentration changes during battery operation.”
This required shiftwork by 3 PhD students at the Paul Scherrer Institute in Switzerland, where there is a neutron source which the researchers could use for their imaging.
“Understanding processes occurring inside the battery means that we can develop better-performing systems that work more efficiently and have longer lifetimes,” says Forner-Cuenca.
But the researchers believe the technique could also be used for other technology.
“For example, chemical reactors are used to make all kinds of products such as plastics, cosmetics, and medicines. Since our method enables visualization of organic molecules in a solution, we anticipate that other industrial applications can benefit from our imaging technique,” says Forner-Cuenca.
