Novel Triaxial Raman Scanning Platform for Evaluating Integrity of Graphite Electrodes in Li-Ion Batteries

The quality of Li-ion batteries is highly related to the crystallinity of the graphite used in their electrodes. Therefore, the development of two-dimensional detection equipment for evaluating the integrity of graphite electrodes is critical. In this study, a triaxial scanning platform was developed for Raman spectroscopy. Two-dimensional Raman mapping of the defects (D band) and stacking (2D band) of graphite electrodes was performed to determine atomic-level variations caused by charging. Through Raman mapping, the effects of constant-current-constant-voltage (CC-CV) and CC-reFLEX fast charging were compared. The graphite damage from CC-reFLEX fast charging was less extensive than that from CC-CV charging. Furthermore, investigations using the triaxial platform revealed that the graphite on a curved electrode exhibited disordered stacking after several charging-discharging cycles. This phenomenon creates safety concerns.