Building a sustainable energy infrastructure requires the use of clean and effective energy storage technologies. Since they now predominate in personal electronic gadgets, lithium-ion batteries hold great promise for dependable grid-level storage and electric vehicles.
However, further development is needed to improve their charging rates and usable lifetimes.
Scientists need to be able to comprehend the processes taking place inside a working battery in order to recognize the constraints of battery performance. This will help them create batteries that are faster to charge and last longer.
A sophisticated synchrotron X-ray or electron microscope is currently needed to view the active battery materials as they operate, but these methods can be expensive and difficult to use, and they frequently cannot image quickly enough to capture the rapid changes occurring in fast-charging electrode materials.
As a result, nothing is known about the ion dynamics at commercially relevant fast-charging rates and on the length scale of individual active particles.
In order to analyze lithium-ion batteries, researchers at the University of Cambridge have created a low-cost lab-based optical microscopy technique. One of the quickest charging anode materials available at the moment is Nb14W3O44, which they looked at as individual particles.
Through a tiny glass window, visible light is directed into the battery, enabling the researchers to observe the dynamic process occurring within the active particles in real time and under realistic non-equilibrium conditions.
These findings provide directly-applicable design principles to reduce particle fracture and capacity fade in this class of materials.Alice Merryweather
This showed that the individual active particles had front-like lithium concentration gradients going through them, causing internal strain that led to the breakage of certain particles. Particle fracture is an issue for batteries because it can cause the fragments’ electrical connections to break, lowering the battery’s capacity to store energy.
“Such spontaneous events have severe implications for the battery, but could never be observed in real time before now,” says co-author Dr. Christoph Schnedermann, from Cambridge’s Cavendish Laboratory.
The researchers’ analysis of a large population of particles using the high-throughput optical microscopy approach revealed that particle breaking is more frequent in longer and particles with greater rates of delithiation.
“These findings provide directly-applicable design principles to reduce particle fracture and capacity fade in this class of materials,” says first author Alice Merryweather, a PhD candidate at Cambridge’s Cavendish Laboratory and Chemistry Department.
Future research into what happens when batteries fail and how to prevent it will be made possible by the methodology’s primary advantages, including the quick data capture, single-particle resolution, and high throughput capabilities. The method is a crucial component in the creation of next-generation batteries since it can be used to analyze practically any kind of battery material.