Flexible fiber-shaped supercapacitors based on hierarchically nanostructured composite electrodes

A novel all-solid-state, coaxial, fiber-shaped asymmetric supercapacitor has been fabricated by wrapping a conducting carbon paper on a MnO₂-modified nanoporous gold wire. This energy wire exhibits high capacitance of 12 mF·cm^-2 and energy density of 5.4 μW·h·cm^-2 with excellent cycling stability. Hierarchical nanostructures and coaxial architectural design facilitate effective contacts between the two core@sheath electrodes and active layers with high flexibility and high performance. This work provides the first example of coaxial fibershaped asymmetric supercapacitors with an operation voltage of 1.8 V, and holds great potential for future flexible electronic devices.