Enhanced Detection of Electrolyte Microleaks by Reduced-Pressure Ion Mobility Spectrometry

Electrolyte leakage is an early indicator of sealing failure and a potential safety risk in lithium-ion batteries, but vapor release from microscopic defects remains difficult to detect because the amount of analyte released is small, transport to the detector is inefficient, and electrolyte vapors contain multiple interfering components. Here, we report a reduced-pressure ion mobility spectrometry (RP-IMS) method that uses reduced pressure as an active sampling strategy for proof-of-concept electrolyte microleak detection. A leakage control gate was used to reduce pressure-dependent variations in ion injection, enabling stable IMS measurements over 0.2-1.0 bar. The RP-IMS system was first characterized under controlled vapor introduction and then evaluated using standard micro-orifices to simulate electrolyte leakage. Reduced-pressure operation accelerated vapor transport, shortened signal recovery, and suppressed interfering product ions from commercial electrolyte vapor. Compared with atmospheric-pressure operation, reduced pressure produced a more concentration-dependent dimethyl carbonate (DMC) monomer response, supporting more reliable recognition of electrolyte markers in complex vapor backgrounds. In simulated microleak experiments, RP-IMS detected DMC vapor from 20 μm standard micro-orifices, and decreasing the pressure from 500 to 200 mbar increased the SNR 4.5-fold. These results show that RP-IMS improves both vapor extraction from small leakage paths and mobility-resolved detection of electrolyte markers, providing a compact approach for early screening of electrolyte microleaks.