Last modified: 2014-10-15
Abstract
Understanding the structure and formation dynamics of the solid electrolyte interphase (SEI) on the electrode/electrolyte interface is of great importance for lithium ion batteries, as the properties of SEI remarkably affect the performances of lithium ion batteries such as power capabilities, cycling life, and safety issues. Although the structure and property of SEI can be inferred from the spectroelectrochemical techniques, such as electrochemical impedance spectroscopy, the high resolution in situ surface characterization technique, such as scanning probe microscopy, is desirable to understand the formation mechanism and growth dynamics of the SEI film at nanoscale level. Herein, we report in situ electrochemical scanning probe microscopy (ECSPM) study of the surface morphology changes of a series of representative electrode materials, such as graphite, silicon anode, and high voltage cathode during initial charging/discharging cycles. A variety of atomic force microscopy operation modes have been applied to trace the SEI growth process and evaluate the SEI film thickness and mechanic property.