A simple electrochemical indicator of lithium plating based on current response at the constant current to constant voltage charging transition

Lithium plating critically degrades lithium-ion batteries and poses safety risks, especially during fast charging. However, practical non-invasive detection remains challenging. We propose a novel diagnostic approach based on transient current kinetics during the constant-current (CC) to constant-voltage (CV) transition. A dimensionless indicator, (Formula presented), is introduced to quantify current decay immediately following the CC–CV switch. By employing a physics-based electrochemical model coupled with side reactions, we elucidate the mechanistic origin of this indicator: it captures the abrupt kinetic redistribution and the inheritance of suppressed intercalation currents caused by the cessation of plating under voltage control. Simulations demonstrate that (Formula presented) exhibits a distinct trend reversal precisely at the onset of lithium plating. This signature provides an early warning approximately 50 cycles before noticeable capacity divergence, offering superior sensitivity compared to voltage relaxation analysis. The robustness of the proposed method is systematically verified across various C-rates (0.2C-1.5C) and complex multi-step CC–CV protocols. Furthermore, the method is validated using independent open-source experimental datasets, confirming its general applicability. Requiring no additional hardware or prolonged rest periods, this strategy offers a cost-effective, real-time solution for enhancing battery safety.