In situ transmission electron microscopy and spectroscopy studies of interfaces in Li ion batteries: Challenges and opportunities

Transmission electron microscopy (TEM) and spectroscopy have been evolved to a stage such that they can be routinely used to probe the structure and composition of the materials with the resolution of a single atomic column. However, a direct in situ TEM observation of structural evolution of the materials in a lithium ion battery during dynamic operation of the battery has never been reported. In this paper, we report the results of exploring the in situ TEM techniques for observation of interfaces in the lithium ion battery during the operation of the battery. A miniature battery was fabricated using a single nanowire and an ionic liquid electrolyte. The structure and composition of the interface across the anode and the electrolyte was studied using TEM imaging, electron diffraction, and electron energy-loss spectroscopy. In addition, we also explored the possibilities of carrying out in situ TEM studies of lithium ion batteries with a solid state electrolyte.