Detection of Nanoscale Local Hotspots for Dendrite Induced Thermal Behaviors

ABSTRACT The localized thermal behaviors induced by metal dendrite growth are critical for enhancing the safety of electrochemical energy storage, yet their underlying mechanisms remain unclear due to the lack of operando, nanoscale thermal sensing techniques. In this study, a quantum thermometer based on nanodiamond nitrogen‐vacancy centers was developed for operando detection of local thermodynamics in Zinc metal dendrite growth with nanoscale spatial resolution. Nanoscale local temperature evolution was tracked dynamically with millisecond temporal resolution via a four‐point optical detection magnetic resonance (ODMR) technique, disclosing that the nanoscale local temperature responded significantly faster than macroscopic indicators in predicting the progress of internal short circuits. Wide‐field imaging quantified local temperature gradients exceeding 1 K/µm at the current density below 60 mA/cm 2 near sub‐micron dendrite tips, corresponding to the very initial stage of internal short circuits (