Ag nanoparticles enhanced vertically-aligned CuO nanowire arrays grown on Cu foam for stable hybrid supercapacitors with high energy density

Ag nanoparticles were uniformly deposited on vertically-aligned CuO nanowire arrays (Ag/CuO NWAs) grown on Cu foam. These composite arrays were used as battery-type electrode materials for highly stable hybrid supercapacitors with excellent energy storage performance. Metallic Ag nanoparticles on the surface of CuO NWAs and Ag atoms diffused into the CuO lattice could improve electrical conductivity of the battery-type electrodes by forming a good ohmic contact and by providing positive and stable pathways for the rapid electron/ion transport. Moreover, surface area of Ag/CuO NWAs electrode was also enhanced with additional active sites formed after Ag deposition. Ag/CuO NWAs demonstrated high stored charge of 1481.3 mC cm(-2), which is two times higher than pristine CuO NWAs. Our binder-free Ag/CuO NWAs electrode displays excellent stored charge retention of 103% after 10000 cycles at 30 mA cm(-2) current density. High-performance hybrid supercapacitor, with Ag/CuO NWAs as the positive electrode and activated carbon as the negative electrode, delivered 0.265 mWh cm(-2) energy density, 48 mW cm(-2) power density and long lifetime stability. We demonstrated that these hybrid supercapacitors could be randomly interconnected and could power various light-emitting diodes. (C) 2018 Elsevier Ltd. All rights reserved.