Crosstalk-Resistant Multifunctional Sensor Based on APTES-Treated Polyaniline/rGO Composite for the Independent Detection of Swelling, Temperature, and CO2

Abstract

Thermal runaway in battery systems involves simultaneous swelling, temperature rise, and CO2 release, necessitating multifunctional sensors capable of detecting these stimuli without signal interference. In this study, we present a crosstalk-resistant multifunctional sensor designed to detect multiple physical stimuli without signal interference. The device incorporates a tempered-glass interlayer that physically and electrically isolates two sensing units. The lower layer, composed of Au and two polyaniline/reduced graphene oxide (PANI/rGO) capacitors, detects both the magnitude and direction of swelling through differential capacitance analysis. The upper sensing layer, fabricated from an APTES-treated PANI/rGO composite, enhances CO2 adsorption and is encapsulated with a selective PDMS layer to decouple temperature and gas responses. The sensor exhibited capacitance variations of 16.58% and 25.04% for square and rectangular swelling packs, respectively, with differential responses of 2.13% and 4.54%, enabling directional discrimination. For temperature sensing, a current variation of 23.8% was observed at 354 K, while CO2 detection at 100 ppm produced a current variation of 12.65%. Temperature effects were compensated using a fitting model, yielding a corrected CO2 response (ygas) of 8.8% at 100 ppm. Coefficients of determination of 0.9520 and 0.9426 were obtained under combined temperature-gas and temperature-only conditions, respectively, confirming the reliability of the model. Overall, the proposed sensor demonstrates a crosstalk-resistant design that enables independent detection of each stimulus while maintaining high selectivity and mechanical stability, underscoring its potential as a multiphysics sensing platform for industrial safety monitoring. © 2001-2012 IEEE.