A tough organohydrogel-based multiresponsive sensor for a triboelectric nanogenerator and supercapacitor toward wearable intelligent devices

Abstract

Hydrogels are usually utilized as materials to fabricate multiresponsive sensors, triboelectric nanogenerators, and supercapacitors, respectively, in wearable devices applications. In order to develop an organohydrogel-based multiresponsive sensor for a triboelectric nanogenerator and supercapacitor, a tough organohydrogel with a triple-network structure was fabricated from poly(vinyl alcohol) (PVA), sodium alginate (SA), and cellulose nanofibrils (CNFs). Due to its unique structure, the hydrogel exhibited a high toughness of 24.5 kJ m⁻². Conductive MXene (MX) nanosheets were functionalized by graphene oxide (GO) to form stable and homogeneous nanocomposites, which were introduced into the organohydrogel matrix as conductive fillers. The MX–GO nanocomposites imparted a high gauge factor (GF) of 2.77 and multiple sensing to the organohydrogel-based sensor such as direction recognition tensile strain sensing, ultra-sensitive pressure strain sensing, and temperature sensing. Meanwhile, the triboelectric nanogenerator (TENG) and supercapacitor were assembled separately with the MX–GO organohydrogel. The short-circuit current (I_SC), open-circuit voltage (V_OC), and short-circuit charge quantity (Q_SC) of the organohydrogel-based TENG in a single-electrode mode achieved 8.7 μA, 145 V, and 42.9 nC, respectively. The organohydrogel-based supercapacitor also showed a high specific capacitance of 5.4 F g⁻¹ and excellent cycling stability (98.2% capacitance retention after 1500 cycles). Therefore, this design approach for organohydrogel-based devices could open a new route for the development of next-generation wearable intelligent devices.