Universal Gas-Sensitive Detection of Various Lithium-Ion Battery Electrolyte Leakages via Ag@Ag₂O-Functionalized SnO₂ Nanoflowers with Abundant Oxygen Vacancies

Lithium-ion batteries (LIBs) provide many benefits, but trace electrolyte leakage can cause serious safety risks such as thermal runaway. Although gas sensors offer a potential solution, the complexity of electrolyte solvents in LIBs makes it challenging to develop sensing materials capable of universally detecting multiple solvent molecules. Here, Ag@Ag₂O-functionalized SnO₂ nanoflowers were synthesized using a self-template pyrolysis strategy for the sensitive detection of both common solvent molecules and widely used electrolytes. These sensors, enhanced by abundant oxygen vacancies introduced by Ag@Ag₂O functionalization, exhibit excellent sensitivity, particularly to dimethyl carbonate, with a response of 106-100 ppm, a low detection limit of 11.76 ppb, and rapid response/recovery times (28/55 s) at an operating temperature of 200 °C. The sensor performance was validated by density functional theory calculations, which corroborated the effectiveness of the sensing material. In simulated LIB leakage scenarios, such as puncture and electrolyte injection, the sensors demonstrated quick responses to various common electrolyte compositions, indicating their potential for practical applications. This study highlights an effective method for fabricating composite sensing materials and emphasizes the practical significance of our universal detection approach for practical monitoring of electrolyte leakage in energy storage devices.