Graphene-enhanced double-network ionogel electrolytes for energy storage and strain sensing

Ionogel electrolytes are critical to electrochemical devices owing to mechanical and electrical properties. Here, graphene-enhanced double-network ionogel electrolytes have been developed with superior properties for energy storage and strain sensing. The uniformly dispersed graphene nanosheets enhance mechanical properties of double-network ionogels and then, provide fluent channels for ion transport. The electrolytes display high ionic conductivity of 0.186 mS cm−1, tensile modulus of 3.64 MPa, and breaking elongation of 217%. The as-prepared electrochemical devices give a high energy capacity of 213 F g−1 at current density of 2 A g−1, and excellent cycling stability beyond 30,000 charge–discharge cycles. In addition, the devices with piezoionic effect present superior sensing properties and have been utilized for real-time monitoring of breath status, which is very important to detection of breath-related disease.