In-Situ X-Ray Diffraction Studies of Battery Electrode Materials for the Microscopic Understanding of the Phase Stability and Performance Correlation

In any electrochemical energy storage system capacity fading is a crucial concern and poses challenges to their long-term stability for any practical uses. There are various characterization techniques for understanding the electrode material, yet it is difficult to nail down the microscopic regions of failure. X-ray diffraction is one of the most important techniques, used for understanding the crystallographic characteristics of the material together with any residual stress, volume change, and other related information. The electrode materials used in rechargeable batteries undergo lithium/sodium ion insertion/extraction process during cycling, causing changes in the electrode materials. The changes may include even permanent structural changes in some cases together with changes like localized strain, volume expansion/contraction, and even complete structural collapse. These cause cyclic instability, and even causing fire accidents in some cases. The in-situ XRD can be integrated to monitor such changes during charging/discharging cycling and thus, may provide a wealth of information to design and develop a robust electrode material for enhanced stability during charging/discharging cycling. The presented review will discuss a few case studies (both Li and Na ion rechargeable batteries) to track such changes in respective cathode materials and thus provide the use of in-situ XRD measurements in electrochemical storage devices.