Electrifying transportation is an essential step towards mitigating climate change. To improve the power, efficiency and safety of electric vehicles, researchers must continue to develop better batteries. All-solid-state lithium batteries (SSBs), which have a solid electrolyte instead of a liquid, are safer than traditional lithium-ion batteries because they are less flammable and more stable at higher temperatures. They could also have higher energy densities than lithium-ion batteries, allowing for longer lasting batteries in smaller sizes for portable electronics and other applications.
A research team led by Joshua Gallaway of Northeastern University in Boston and scientists at the Department of Energy’s (DOE) Argonne National Laboratory recently tested how the composition of thick cathodes affected electrochemical reactions in SSBs. The team used the resources of the Advanced Photon Source (APS), a DOE Office of Science user facility at Argonne. Their discoveries were published in the journal ACS Energy Letters.
“How all-solid-state batteries are designed will determine what their applications will be and how they will be optimized moving forward,” — Josh Gallaway, Northeastern University
Gallaway relates batteries to sandwiches — they are comprised of an anode on one side, a cathode on the other, a separator in the middle, and electrolyte solution throughout. When batteries provide power, lithium ions flow from the anode to cathode through the electrolyte. While SSBs don’t require traditional separators because the electrolyte separates the anode and cathode, they do require thick cathodes.
In this study, Gallaway and his colleagues evaluated batteries with thick cathodes that were comprised of two materials: a sulfide solid electrolyte called LPSC and an NMC (nickel, manganese, cobalt) cathode active material (CAM). They altered the composition of these two materials, so some batteries were 80% CAM, 20% LPSC, while others were 70% CAM, 30% LPSC and 40% CAM, 60% LPSC. Then, they used X-ray imaging and scattering at APS beamline 6-BM-A to measure six slices within the cathode and solid-state electrolyte.
Read more on the Argonne website
Image: An all-solid-state battery on an experimental stage used in the study. The battery is compressed in a vise and has a laser shining on it to align the X-ray beam.
Credit: Josh Gallaway/Northeastern University, Boston.