Battery performance mapped using X-ray microscopy

Developed at Berkeley Lab’s Advanced Light Source, the new imaging tool allows the team to observe nanoscale changes inside lithium-ion battery particles as they charge and discharge. It uses two beams that provide scanning transmission X-ray microscopy (STXM), where an extremely bright X-ray beam is focused onto a small spot. A specially designed “liquid electrochemical STXM nanoimaging platform” uses soft X-rays to image lithium iron phosphate particles as they delithiate (charge) and lithiate (discharge) in a liquid electrolyte.

Among its findings, the team discovered that the charging process doesn’t happen uniformly across the surface of a particle, something that likely plays a role in battery degradation over time. The research, published in the journal Science, could help scientists improve the performance of rechargeable batteries for electric vehicles and mobile devices.

“The platform we developed allows us to image battery dynamics at the mesoscale, which is between a few nanometres and a few hundreds of nanometres,” said research lead Will Chueh, a faculty scientist at the Berkeley Lab, and an assistant professor of materials science & engineering at Stanford.