An Air‐Stable MXene Bio‐Interfacing Thin Film Electrode

Abstract MXene exhibits an excellent ion‐electron dual conduction mechanism, making it a promising candidate for bio‐interfacing electrodes. However, the exposed Ti atoms on MXene flakes are prone to oxidation in air, leading to serious degradation which impedes its application as bioelectronic materials. Herein, a new MXene thin film protected by reduced graphene oxide (rGO) (namely rGM), resulting in an air‐stable MXene bio‐interfacing thin film electrode with high charge transfer capability is reported. The protective layer rGO effectively shields the conductive layer MXene from air oxidation, thereby significantly enhancing the air stability. After 40 days in the air (25 °C, 40% RH), the sheet resistance of rGM thin film (135.9 ± 2.3 to 312.6 ± 4.5 Ω sq −1 ) exhibits negligible increase compared to pure MXene thin film (145.0 ± 2.3 to 2,152.8 ± 6.8 Ω sq −1 ). A built‐in electric field (BIEF) is generated by the redistribution of charges at the rGO@MXene heterojunction interface, which enhances the charge transfer efficiency and helps reduce the interfacial impedance between the electrodes and biological tissues. Together with its thin film characteristic, rGM is applicable for advanced automatic external defibrillator (AED) electrodes, which is essential for advancing emergency treatment research related to cardiac arrest.