Operando X-ray diffraction during battery cycling at elevated temperatures: A quantitative analysis of lithium-graphite intercalation compounds

Abstract

The application of in situ or operando characterization techniques is highly important to gain a deeper understanding of the electrochemical and degradation processes that occur during battery cycling. This work presents the first results of operando X-ray diffraction (XRD) studies of a battery at elevated temperatures. Our in situ-cell was developed to simultaneously investigate the structural and electrochemical behaviors of batteries at room temperature and elevated temperatures. The cell design was applied to high temperature operando XRD measurements of graphite half-cells (vs. Li/Li+). New results on the structural behavior of graphite during lithium intercalation and deintercalation were obtained at elevated temperature (30 °C and 47 °C). At these temperatures, the classical staging mechanisms does not occur, and instead, several stages coexist. The average spacing between the graphene layers was calculated for phases in the single-stage region and those at which several stages coexist for different depths of charge and discharge and at different C-rates. Through this work, we aim to stimulate further operando XRD studies on battery materials' temperature behavior during cycling.