Electrochemical Cells for In-Situ XRD Studies of Insertion and Extraction Mechanisms of Lithium in Anode Materials for Lithium Ion Batteries Tested at Aluminum Model Electrodes

Lithium ion batteries (LIBs) are already widely used in a variety of different applications in daily life and are now facing new challenges requiring significant enhancement of power, lifetime, cost, safety and flexibility. Our aim with regard to purposeful improvement of LIBs is to get insight on the atomic scale into the mechanisms during charging and discharging. Applying in-situ X-ray diffraction (in-situ XRD) using synchrotron light the alloy phase evolution during galvanostatic electrochemical lithiation (charging) and delithiation (discharging) of an Al model anode was studied. It was found that the alloy phase Li1Al1 is formed and dissolved, respectively, reproducibly and reversibly. To perform in-situ XRD two electrochemical cells, penetrable for X-ray radiation, were constructed, which can be operated on top of the diffractometer at synchrotron radiation facilities. With this approach it is possible to correlate electrochemistry, phase evolution and crystallographic orientation.7