Highly flexible and conductive nanoporous Ag as good substrate for flexible hybrid supercapacitors

Abstract

Flexible electrode materials with high volumetric capacitance are promising to applications in portable and wearable capacitive storage devices. Here, we utilized the highly flexible and conductive NP-Ag substrate to successfully develop a flexible nanoporous Ag@Co(OH)2 (NP–Ag@Co(OH)2) thin film electrode. After 100 multiple bending cycles, the NP-Ag@Co(OH)2 electrode can keep the original nanostructures and flexibility. The flexible NP-Ag@Co(OH)2 electrode exhibits the high volumetric capacitance of 929 F cm−3 at a current density of 2 A cm−3, which is higher than many reported supercapacitor electrodes. The flexible NP-Ag@Co(OH)2 electrode exhibits good supercapacitor performance even under the bending state. Moreover, the as-assembled NP-Ag@Co(OH)2 symmetric supercapacitor device has high energy density of 20.07 mWh cm−3 at power density of 0.85 W cm−3. The device supercapacitor retains 75% capacitance of the initial value at 2 A cm−3 after 2000 cycles. This work provides an insight into the rational design of the highly flexible, high-performance supercapacitor electrodes with the potential application in portable or wearable energy storage devices.