Sensitivity and reliability of key electrochemical markers for detecting lithium plating during extreme fast charging. (February 2022)

• Record Type: Journal Article
• Authors: Chinnam, Parameswara R.; Tanim, Tanvir R.; Dufek, Eric J.; Dickerson, Charles C.; Li, Meng
• Is Part Of: Journal of energy storage. Volume 46(2022)
• Publication Date: 2022-02
• Subjects: Lithium-ion battery -- Extreme fast charging -- Electrochemical Li plating -- Battery safety; XFC extreme fast charging -- EC electrochemical -- CC constant current -- EOL end of lithiation -- dOCV differential open circuit voltage -- SOC state of charge -- SEI solid electrolyte interphase -- Li lithium; Energy storage -- Periodicals; Energy storage -- Research -- Periodicals; 621.3126
• DOI: 10.1016/j.est.2021.103782
• Languages: English
• ISSNs: 2352-152X

Abstract

Highlights: Distinct sensitivity & unreliability issues exist in Li plating detection for fast charging. Higher charging rate hinders reversibility of plated Li and dQ.dV −1 signature. dQ.dV −1 and dOCV.dt −1 signatures show completely opposite behavior with charging rate. End of charge rest voltage evolution strongly dictated by chemical interaction pathways. Tracking multiple detection signatures concurrently provides reliable detection. Abstract: Lithium plating is one of the key challenges for enabling extreme fast charging (XFC, ≤10 to 15 min charging at ≥6C) in graphite-based lithium-ion batteries. Significant R&D effort has been focused on how to mitigate Li plating. Parallel effort is also being devoted to developing methods to detect Li plating when and if it happens during fast charging. In that regard, electrochemical (EC) signature-based detection techniques are less resource intensive, more convenient, and more practical from an end-user application perspective. However, a comprehensive understanding of key plating related EC signatures for extreme fast charging is presently unavailable. In particular, there exist distinct issues of unreliability with key plating-related EC signatures—e.g., incremental capacity (dQ.dV −1 ), differential OCV (dOCV.dt −1 ), end of lithiation (EOL) rest voltage—at XFC conditions, and the underlying reasons have not been explored and identified methodically. Using a comprehensive test matrix and XFC conditions with Li/graphite half cells, this article highlights the unreliability issues associated with the EC Li plating diagnostics and explains the underlying root cause. This study finds distinct sensitivity and unreliability issues with plating related dQ.dV −1, dOCV.dt −1, and EOL rest voltage signatures with charging rates. The complex interaction between graphite and plated Li that happens through multiple competing mechanisms —Li stripping and chemical intercalation— at different charging rates is at the core of the sensitivity and unreliability issue.