High-performance flexible supercapacitors based on electrochemically tailored three-dimensional reduced graphene...

A simple approach for growing porous electrochemically reduced graphene oxide (pErGO) networks on copper wire, modified with galvanostatically deposited copper foam is demonstrated. The as-prepared pErGO networks on the copper wire are directly used to fabricate solid-state supercapacitor. The pErGO-based supercapacitor can deliver a specific capacitance (C_sp) as high as 81±3 F g^-1 at 0.5 A g^-1 with polyvinyl alcohol/H₃PO₄ gel electrolyte. The C_sp per unit length and area are calculated as 40.5 mF cm^-1 and 283.5 mF cm^-2, respectively. The shape of the voltammogram retained up to high scan rate of 100 V s^-1. The pErGO-based supercapacitor device exhibits noticeably high charge-discharge cycling stability, with 94.5% C_sp retained even after 5000 cycles at 5 A g^-1. Nominal change in the specific capacitance, as well as the shape of the voltammogram, is observed at different bending angles of the device even after 5000 cycles. The highest energy density of 11.25 W h kg^-1 and the highest power density of 5 kW kg^-1 are also achieved with this device. The wire-based supercapacitor is scalable and highly flexible, which can be assembled with/without a flexible substrate in different geometries and bending angles for illustrating promising use in smart textile and wearable device.