In Operando Acoustic Detection of Lithium Metal Plating in Commercial LiCoO2/Graphite Pouch Cells

The characterization and detection of lithium metal plating during standard operation of commercial Li-ion batteries has been a long-term challenge; the nature of lithium metal plating is unpredictable and highly dependent on operating temperature and charge rate. In operando detection of lithium plating is critical for ongoing and future developments of conventional Li-ion batteries, including fast charging capabilities, extreme temperature applications, and lithium metal secondary batteries. In this study, we describe the use of acoustic ultrasound to detect lithium metal plating on commercial graphite anodes within a standard form factor. Extending from previous work on ultrasound as a battery diagnostic tool, this proof-of-concept study delineates statistically significant linear relationships between ultrasonic time-of-flight and graphite staging, and acoustic time-of-flight and post mortem electrochemical measurements to characterize the extent of lithium metal plating.