Researchers at the University of Cambridge in the UK have developed low-cost laboratory-based optical microscopy technique to study lithium-ion batteries.
The high-throughput capabilities of the optical microscopy technique enabled the researchers to analyse a large population of particles, revealing that particle cracking is more common with higher rates of delithiation and in longer particles.
The team examined individual particles of Nb14W3O44, by sending visible light into the battery through a small glass window, which enabled them to watch the dynamic process within the active particles, in real time, under realistic non-equilibrium conditions.
The technology is an alternative to synchrotron X-ray or electron microscopy techniques.
The paper outlining the research was published in the journal Nature Materials.
The new technique revealed front-like lithium-concentration gradients moving through the individual active particles, resulting in internal strain which caused some particles to fracture— a concern for batteries as it can lead to electrical disconnection of the fragments, reducing the storage capacity of the battery.
First author of the paper Alice Merryweather, a PhD candidate at Cambridge’s Cavendish Laboratory and Chemistry Department, said: “These findings provide directly-applicable design principles to reduce particle fracture and capacity fade in this class of materials.”
Moving forward, the key advantages of the methodology – including the rapid data acquisition, single-particle resolution, and high throughput capabilities – will enable further exploration of what happens when batteries fail and how to prevent it.
The technique can be applied to study almost any type of battery material.
Read the research paper here.