Imidazolium ionic liquid-endowed polyacrylamide/sodium alginate carbon-based hydrogels with a high voltage window and high sensitivity for wearable flexible electronic devices

The imidazolium ionic liquid is introduced into the traditional dual-network hydrogel via irregular aggregation. • The hydrogels exhibit high voltage windows and high sensitivity due to the synergistic effect. • The carbon-based hydrogel is applicable to wearable flexible electronic devices. The uneven dispersion of carbon particles restricts the mechanical properties and electrical conductivity of carbon-based nanomaterials, thus hindering their widespread application in wearable flexible electronic devices. Herein, imidazolium ionic liquids (ILs) in an irregularly aggregated form are perfectly incorporated into the polymer molecular chains of polyacrylamide/sodium alginate (PAM/SA) hydrogels. Interface and kinetic simulations clarify that the ionic liquid (IL) not only reinforces the hydrogel network structure, but also effectively improves the dispersion of graphite (KS-6), enhances the hydrogel's electrochemical performance, and endows the hydrogel with multiple excellent properties. The test results show that the composite PAM/SA carbon-based hydrogel achieves a wide voltage window (1.8  V ) and high sensitivity (GF = 7.03). Moreover, the hydrogel's mechanical properties (maximum elongation at break: 613.69%) and electrical conductivity (maximum value: 34.24 mS cm −1 ) are also significantly improved. Furthermore, the application value of this series of hydrogels in energy storage and sensing is demonstrated. For example, they can be used to fabricate flexible capacitors and as sensors to detect human joint movements and subtle vibrations. This research provides a feasible approach for the design of carbon-based hydrogels and an ideal set of candidate materials for the development of flexible electronic devices.