High-Frequency Electrochemical Impedance Spectroscopy for Detecting Li Deposition Toward Assessing Thermal Stability in LiBs

Li deposition decreases the thermal stability of Li-ion batteries (LiBs), reducing safety. We have developed High-Frequency Electrochemical Impedance Spectroscopy (HF-EIS) to detect Li deposition from the high-frequency real part impedance in the MHz range. The evaluation of the relationship between the onset temperature of thermal runaway and the change in high-frequency impedance demonstrated that HF-EIS is capable of quantitatively evaluating the safety associated with Li deposition. The HF-EIS can be a diagnostic tool for safety quantification and can contribute to the development of battery materials by reducing the cost of destructive testing.