Equipment development for characterization of microstructural evolution and 3D reconstruction of lithium-ion battery electrodes based on Broad Ion Beam-Scanning Electron Microscopy (BIB-SEM)

Silicon-based anodes have emerged as a promising next-generation electrode material due to their high specific capacity and abundant raw material reserves. However, the inherent and significant volume expansion of silicon-based anodes intensifies the mechanical-electrochemical coupling issues within lithium-ion batteries (LIB). Consequently, the quantitative characterization of microstructural evolution due to expansion at different State Of Charge (SOC) is essential for understanding the performance degradation of these batteries. This paper addresses the challenge of obtaining accurate microstructural models of LIB electrodes, a task that requires both a large field of view and high resolution. We have independently designed and developed an argon ion beam cutting apparatus based on scanning electron microscopy (SEM). This work introduces a novel technique that utilizes an argon ion beam external to the SEM chamber, along with a specially designed three-dimensional sample stage. This effectively resolves issues related to nanoscale precision in sample positioning and prevents contamination of the chamber during the cutting process. By leveraging this approach, we enable the quantitative characterization of three-dimensional reconstructions of the microstructure of battery electrodes, achieving both a large field of view and high resolution. With this equipment, we investigate the microstructural changes in silicon-based anodes under various SOC.