Detection of lithium plating in lithium-ion batteries by distribution of relaxation times

In the complex working environment, lithium plating brings great challenges to the safety of lithium-ion batteries, and reliable and non-destructive online detection methods are extremely hard to achieve. Herein, we propose a method for non-destructive detection of lithium plating in batteries using distribution of relaxation times (DRT). The coin and pouch cells are used to identify the peaks appearing in DRT, and the influence of lithium plating on the charge transfer process of cathode/anode and the changes caused in the DRT spectrum are studied. The DRT results show that lithium plating will change the state of charge (SOC) of the cathode, causing the peak of the charge transfer process to move toward high frequencies and become weaker. Meanwhile, the peak intensity of the anode charge transfer process decreases because another new charge transfer process occurs on the surface. This changing trend has a strong correlation with the amount of lithium plating and its deviation from the normal range can be regarded as an indicator of existence of lithium plating. This method may provide new insights into the understanding of lithium plating and further expand the application of electrochemical impedance spectroscopy on the safety warning of lithium-ion batteries.