A one-dimensional Ag NW@NiCo/NiCo(OH)2 core-shell nanostructured electrode for a flexible and transparent asymmetric supercapacitorElectronic supplementary information (ESI) available. See DOI: 10.1039/c9ta01303b

Flexible and transparent electrodes based on one-dimensional Ag nanowire@NiCo/NiCo(OH) 2 core-shell nanostructures with a tunable composition were fabricated by electrodeposition. The highly conductive Ag nanowire (NW) network was considered as a current collector, and the NiCo/NiCo(OH) 2 nanostructures could grow on the surface of the Ag NWs, providing active materials with the synergistic effect of Ni and Co elements. The core-shell nanostructures integrate the advantages of metallic NWs for effective charge transport, the NiCo alloyed layer for a stable structure, and NiCo(OH) 2 for high electrochemical performance. The composite electrode with a transmittance of 54.3% delivers a high areal capacitance of 22.2 mF cm −2 at a current density of 0.1 mA cm −2 , and an excellent capacitance retention rate of 91.9% at 100 mV s −1 after 5000 cycles. Furthermore, an asymmetric supercapacitor composed of the Ag NW@NiCo/NiCo(OH) 2 cathode and the Ag NW/graphene anode achieves a maximum areal capacitance of 9.6 mF cm −2 at a current density of 0.2 mA cm −2 , high energy density of 3.0 W h kg −1 and power density of 3.5 W kg −1 . The Ag NW@NiCo/NiCo(OH) 2 core-shell nanostructured electrode shows great potential for flexible and transparent energy storage devices. One-dimensional Ag nanowire@NiCo/NiCo(OH) 2 core-shell nanostructures with a tunable composition are constructed by electrodeposition, showing potential applications in transparent and flexible supercapacitors.