A new in situ transmission electron microscopy technique enabled ORNL researchers to image the snowflake-like growth of the solid electrolyte interphase from a working battery electrode. (Photo courtesy ORNL)

Using a new microscopy method, researchers at Oak Ridge National Laboratory can image and measure electrochemical processes in batteries in real time and at nanoscale resolution.

Scientists at ORNL used a miniature electrochemical liquid cell that is placed in a transmission electron microscope to study an enigmatic phenomenon in lithium-ion batteries called the solid electrolyte interphase, or SEI, as described in a study published in Chemical Communications.

The SEI is a nanometer-scale film that forms on a battery’s negative electrode due to electrolyte decomposition. Scientists agree that the SEI’s formation and stability play key roles in controlling battery functionality. But after three decades of research in the battery field, details of the SEI’s dynamics, structure, and chemistry during electrochemical cycling are still debated, stemming from inherent difficulties in studying battery electrode materials in their native liquid environment.

“We’ve used this novel in situ method to understand the dynamics of how this layer forms and evolves during battery operation,” said Raymond Unocic, ORNL research and development staff scientist. [Read more…]