Although graphene has been widely used as a nano-filler to enhance the conductivity of porous materials, it is still an unsatisfactory requirement to prepare graphene-based sponge porous materials by simple and low-cost methods to enhance their mechanical properties and make them have good sensing and capacitive properties. Graphene platelets (GnPs) were prepared by the thermal expansion method. Graphene-based sponge porous materials were prepared by a simple method. A flexible sensor was formed and supercapacitors were assembled. Compared with other graphene-based composites, the graphene-based composite sponge has good electrical response under bending and torsion loading. Under 180° bending and torsion loading, the maximum resistance change rate can reach 13.9% and 52.5%, respectively. The linearity under tension is 0.01. The mechanical properties and capacitance properties of the sponge nanocomposites were optimized when the filler fraction was 1.43 wt.%. The tensile strength was 0.236 MPa and capacitance was 21.4 F/g. In cycles, the capacitance retention rate is 94.45%. The experimental results show that the graphene-based sponge porous material can be used as a multifunctional flexible sensor and supercapacitor, and it is a promising and multifunctional porous nanocomposite material.
Keywords: flexible sensor; graphene; multifunctional; sponge porous materials; supercapacitor.