Detecting onset of lithium plating during fast charging of Li-ion batteries using operando electrochemical impedance spectroscopy

• Published in: Cell reports physical science Vol. 2; no. 10; p. 100589
• Main Authors: Brown, David E., McShane, Eric J., Konz, Zachary M., Knudsen, Kristian B., McCloskey, Bryan D.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 20.10.2021; Elsevier
• Subjects: electrochemical impedance spectroscopy; electrochemistry; ENERGY STORAGE; extreme fast charging; graphite; lithium plating; lithium-ion battery; mass spectrometry titrations; solid-electrolyte interphase (SEI); solid-electrolyte interphase (SEI); mass spectrometry titrations; electrochemical impedance spectroscopy; electrochemistry; extreme fast charging; graphite; lithium-ion battery; lithium plating
• ISSN: 2666-3864; 2666-3864
• DOI: 10.1016/j.xcrp.2021.100589

Electrochemical plating of Li metal on the graphite electrode is the key limitation behind slow charging times of Li-ion batteries (LIBs) in electric vehicles (EVs). Currently, electrochemical methods to detect the onset of Li plating while a battery is fast charging are sparse. In this study, we use operando electrochemical impedance spectroscopy to reliably detect the onset of Li plating on graphite electrodes in three-electrode LIBs. An increase in the graphite solid-electrolyte interface (SEI) resistance indicates that Li plating has occurred. By cross-validating with a highly sensitive ex situ chemical titration, we determine that this technique can detect very small amounts of plated Li (<0.6% of the graphite electrode’s capacity). We also offer physical explanations for the observed impedance behavior. Finally, we show that this technique can be applied to standard two-electrode LIB systems, making the method an important step toward safely implementing fast charging protocols for LIBs in EVs. [Display omitted] •Li plating onset detected on graphite anode using electrochemical impedance spectroscopy•High Li detection sensitivity (<0.6% graphite capacity) during high charge rates (4C)•Plating detection cross-validated with ex situ mass spectrometry Li metal titrations•Impedance feasibility demonstrated in commercially relevant two-electrode cells Electric vehicle Li-ion battery charging times are slow to prevent lithium plating, a detriment to cycle life and safety, on the graphite electrode. Brown et al. detect the onset of lithium plating during fast charging using electrochemical impedance spectroscopy. With further development, this technique could enable fast charging in existing charging infrastructure.