Advanced Electrochemical Diagnostics Validation for Early Detection of Lithium Plating in Lithium-Ion Batteries

The increasing push for electrified transportation and stationary energy storage demands that lithium-ion batteries (LIBs) perform under more aggressive charging conditions. Meeting such requirements without compromising safety remains a key challenge for the industry. One of the persistent obstacles to achieving fast safe charging is lithium plating, a degradation process that leads to capacity fading, increased internal resistance, and elevated safety risks (e.g., internal short-circuits). In this study, we combine in situ electrochemical diagnostics, specifically incremental capacity analysis (ICA), differential voltage analysis (DVA), and electrochemical impedance spectroscopy (EIS), with post-mortem characterization methods, including computed tomography (CT), scanning electron microscopy (SEM), X-ray diffraction (XRD), solid-state ⁷Li nuclear magnetic resonance (NMR), to assess lithium plating behavior under varied conditions and gas chromatography-mass spectrometry (GC-MS) to analyze the electrolyte. Commercial 18650 Cells (NCA cathode and SiOx-graphite anode) were cycled at -10 and 25 °C to induce different degradation modes, enabling a comparative analysis of lithium plating. Key electrochemical signatures (e.g., increased charge transfer resistance and accelerated solid electrolyte interface (SEI) growth) were correlated with physical evidence of lithium deposition. Notably, solid-state ⁷Li NMR detected metallic lithium only in cells aged at -10 °C confirming that low temperature operation promotes plating. Importantly, while ICA and DVA offer a practical, field-deployable solution for early detection of lithium plating in BMS applications, advanced postmortem techniques, like NMR and CT, are used for laboratory-based validation of the degradation mechanism. Our results provide a realistic pathway toward smarter, safer battery management strategies.