An Investigation of Stress Evolution and Progressive Phase Transformations in Tin during Electrochemical Lithiation Cycling
Chun-Hao Chen (Brown University), Eric Chason (School of Engineering, Brown University), Pradeep Guduru (Brown University)
Lithium ion batteries: When Chemistry meets Mechanics
Wed 10:45 - 12:15
Salomon 003
Tin as an anode in lithium ion batteries offers large theoretical charge capacity (994 mAhg-1), but also exhibits irreversible capacity loss through mechanical degradation, which results from the stresses generation due to large volume changes (~ 260%). In order to understand and possibly control mechanical degradation, a systematic investigation is carried out by selectively growing individual Li-Sn phases at specific potentials and measuring the corresponding stress evolution. Experiments are carried out on thin films of electrodeposited tin films on elastic substrates, while stress evolution is measured by monitoring the substrate curvature during cycling. Focused ion beam (FIB) milling and XRD examination is used to identify the lithiated phases formed. The thicknesses of the lithiated phase were measured in the FIB cross-sectional images, which are used to interpret the curvature data in terms of stress evolution.