Analyzing Batteries One Slice At A Time

Researchers in France and Japan have demonstrated a procedure for preparing nanometer-thick cross sections of solid-state lithium-ion batteries and analyzing the thin slices in a transmission electron microscope (Chem. Mater., DOI: 10.1021/cm7033933). The first-of-its-kind study revealed structural defects within the batteries' layers. It also showed that interfaces that are initially pristine in unused batteries deteriorate upon charging and discharging as minute quantities of cobalt, vanadium, silicon, and other materials migrate from one battery component and contaminate adjacent ones. That type of information may ultimately lead to improved performance and longevity for rechargeable batteries that are used in cell phones and laptops. Loic Dupont and Adrien Brazier of the University of Picardie Jules Verne, in France, and coworkers there and at Tohoku University, in Japan, fabricated multilayered thin-film batteries consisting of a LiCoO₂ cathode, a Li-V-Si-based solid electrolyte layer, a SnO anode, and other components. The researchers used a focused ion beam to cut battery slices less than 100-nm thick and analyzed the specimens' physical structure and chemical composition with nanoscale resolution.