Layered Graphene/Hydrogel-Based Multi-Modal Sensors Enabled by Ion-Electron Synergistic Conduction.

Some scenarios necessitate high strain sensitivity for subtle motion detection, while others require stable electrical performance under deformation. Integrating these seemingly conflicting characteristics into one platform remains challenging. Herein, stretchable mechanical-bioelectric multi-modal sensors with low interfacial impedance, excellent environmental stability, excellent self-healing ability and biocompatibility, are fabricated by integrating hydrogels with chemical vapor deposition grown graphene films. Graphene with high electron mobility and biocompatibility allows long-term and sensitive signal acquisition, while hydrogels with multiple dynamic interactions exhibit not only excellent self-healing ability but also excellent stress relaxation to mitigate strain damage. A robust interface with wrinkle structure is formed owing to the nano-scaled thickness of graphene and dynamic interactions of hydrogels, where ion-electron synergistic conduction offers ion and electron charges, enhancing the capacitive coupling process of ionic and electronic current. Benefiting from these judicious designs, the layered composites exhibit low swelling ratio (∼22%), low skin interfacial impedance (28.70 kΩ at 100 Hz), high self-healing efficiency (95.24%), wide sensing range (∼500%), and excellent durability (∼1000 cycles to 150% strain). Important applications in physiological signal detection, information transmission, and spatial force distribution mapping, are demonstrated. Self-healing capability is verified in monitoring urinary bladder activities, offering opportunities for designing high-performance, multifunctional graphene-based bioelectronics.