Ultrasensitive Detection of Electrolyte Leakage from Lithium-Ion Batteries by Ionically Conductive Metal-Organic Frameworks

A new type of electronic sensor fabricated with thin films of unique ionically conductive metal-organic frameworks (IC-MOFs) for detecting lithium-ion battery (LIB) electrolyte leakage was developed. Sensing signals based on the output current, capacitance, and equivalent resistance were investigated and compared comprehensively. Rapid detection of dimethyl carbonate (50 ppb) and LIB electrolyte (20 nL) leakage could be achieved within seconds. Mechanistic studies showed that direct interaction between analytes and metal ions in IC-MOF thin films might account for the sensor's ultrahigh sensitivity and response speed. Real-time detection was further demonstrated by testing an actual LIB displaying electrolyte leakage. The sensor was able to signal the leakage while the voltage of the leaking battery was kept at almost the same level as that of a pristine battery for several hours, which shows the capability of hours of early warning time for our sensors. Moreover, long-term device stability (tested over 6 months in ambient atmosphere, with negligible change) was demonstrated.