Researchers have captured the first atomic-level images of finger-like growths that trigger battery fires.
…In a lithium-ion battery, dendrites can grow under some charging conditions and cause short circuits. Researchers have already known of the growth of the dendrites inside the batteries. But until now, they have not been able to get atomic-scale images of dendrites or other sensitive battery parts. To their surprise, dendrites are crystalline, not the irregular shaped depicted in previous electron microscope shots.
Researchers not only looked at the structure of dendrite but also at a coating called SEI that develops as the dendrite reacts with the surrounding electrolyte. The new technique also revealed the locations of individual atoms in both the crystal and its SEI coating.
“We were really excited. This was the first time we were able to get such detailed images of a dendrite, and we also saw the nanostructure of the SEI layer for the first time,” said Yanbin Li from Stanford. “This tool can help us understand what different electrolytes do and why certain ones work better than others.”