By: Jennifer Rocha

Brookhaven National Laboratory study also provides the first direct experimental evidence to support a particular model of the electrochemical reaction.

Story content courtesy of Brookhaven National Laboratory, US

Using a new method to track the electrochemical reactions in a common electric vehicle battery material under operating conditions, scientists at the U.S. Department of Energy’s Brookhaven National Laboratory have revealed new insight into why fast charging inhibits this material’s performance. The recently-published results could provide guidance to inform battery makers’ efforts to optimize materials for faster-charging batteries with higher capacity.

Many previous methods used to analyze such battery materials have produced data that average out effects over the entire electrode. These methods lack the spatial resolution needed for chemical mapping or nanoscale imaging, and are likely to overlook possible small-scale effects and local differences within the sample, Wang explained.

To improve upon those methods, the Brookhaven team used a combination of full- field, nanoscale-resolution transmission x-ray microscopy (TXM) and x-ray absorption near-edge spectroscopy (XANES) at the National Synchrotron Light Source (NSLS), a DOE Office of Science User Facility that provides beams of high-intensity x-rays for studies in many areas of science. These x-rays can penetrate the material to produce both high-resolution images and spectroscopic data-a sort of electrochemical “fingerprint” that reveals, pixel by pixel, where lithium ions remain in the material, where they’ve been removed leaving only iron phosphate, and other potentially interesting electrochemical details.

This work was supported by a Laboratory Directed Research and Development (LDRD) project at Brookhaven National Laboratory. The use of the NSLS was supported by the U.S. Department of Energy’s Office of Science.