Flexible electrodes with enhancement of electronic-ionic conductivity for electrophysiological signal monitoring

The transmission of electrophysiological signals to the skin is subject to decay, which renders them challenging to detect. To improve the signal-to-noise ratio, we need electrodes with low skin impedance that are also flexible to avoid movement artifacts. Low skin impedance requires not only low resistivity but also high ionic conductivity to accommodate electrophysiological signals of different frequencies. By blending two electronic-ionic conductors, i.e., PEDOT:PSS and Ti 3 C 2 T x MXene, we reported a film electrode with high conductivity (∼2780 S/cm) and high volumetric capacitance (31.3 F/cm 3 ). Low electrochemical impedance was thereby achieved (41.2 Ω cm² at 100 Hz) with the film thickness of approximately 60 nm. Such an excellent mixed conductivity, enables the accurate monitoring of electrophysiology signals that can be used in wearable electronic devices. Monitoring electrophysiological signals is of vital for the clinical diagnosis. In this work, we combined two electronic-ionic conductors, i.e., PEDOT:PSS and Ti 3 C 2 T x MXene, to achieve high conductivity and low skin interface impedance. In addition, a variety of electrophysiological signals were precisely recorded. • Combination of MXene with conductive polymer yields excellent flexible electrode. • High conductivity and high volumetric capacitance are obtained simultaneously. • Film electrode with low skin impedance facilitates the precise recording of electrophysiological signals.