Impedance Characteristics of Lithium Plating at Low Temperatures Based on Electrochemical Impedance Spectroscopy and Distribution of Relaxation Times

Lithium plating has the potential risk of capacity degradation and internal short circuiting in lithium-ion batteries (LIBs). This study investigates the impedance characteristics of lithium plating at low temperatures through combination of electrochemical impedance spectroscopy (EIS) and distribution of relaxation times (DRT) methods. Results show that compared to ohmic and SEI film impedance, the charge transfer impedance has the fastest growth in initial lithium plating, and the DRT spectrum indicates that the cathode charge transfer impedance is the main increase. With lithium plating continuing, ohmic impedance (R0), SEI film impedance (Rsei), and charge transfer impedance (Rct) grow at an increasing rate. This could be due to the mutual promotion between lithium plating and the decline of electrochemical reaction kinetics, leading to the evolution of impedance. Meanwhile, the trend of Rct changes is inverted. The anode charge transfer impedance increases faster than the cathode, being the main increase. Besides, a higher charge rate tends to cause a faster increase in impedance, and it is limited by the high polarization effect. This study could help in the rapid and nondestructive detection of lithium plating in LIBs through impedance detection.