Sensitive sensors based on bilayer organic field-effect transistors for detecting lithium-ion battery electrolyte leakage

The leakage of flammable and explosive lithium-ion battery (LIB) electrolytes can be one of the early symptoms of battery malfunction and can even lead to spontaneous battery combustion or electric car explosion. Therefore, it is necessary to find a rapid and simple method to monitor any leakage of LIB electrolytes. However, LIB electrolytes are generally composed of volatile and redox neutral carbonate solvents. Trace amounts of electrolyte leakage are difficult to detect effectively and rapidly by existing compact sensors. Here, for the first time, we propose a strategy that cooperatively combines the sensitivity of organic field-effect transistors (OFETs) and the selectivity of biurea receptors to detect LIB electrolyte leakage. The fabricated sensors show much higher sensitivity than the pristine sensor without receptors, and the detection limit of the sensor toward diethyl carbonate was 1.4 ppm. Trace amounts of LIB electrolyte leakage could be detected effectively in seconds, with 200 nL electrolyte leakage leading to a 3% response. We also demonstrate the real-time detection of LIB electrolyte leakage by our OFET sensors. The excellent performance of the receptor-coated OFET sensor makes it a good candidate for LIB safety monitoring and provides a promising platform for the development of sensing technologies.