Ultrathin nickel hydroxide on carbon coated 3D-porous copper structures for high performance supercapacitors.

An ultrathin nickel hydroxide layer electrodeposited on a carbon-coated three-dimensional porous copper structure (3D-C/Cu) is suggested as an additive and binder-free conductive electrode with short electron path distances, large electrochemical active sites, and improved structural stability, for high performance supercapacitors. The 3D-porous copper structure (3D-Cu) provides high electrical conductivity and facilitates electron transport between the Ni(OH)2 active materials and the current collector of the Ni-plate. A carbon coating was applied to the 3D-Cu to prevent the oxidation of Cu, without degrading the electron transport behavior of the 3D-Cu. The 3D-Ni(OH)2/C/Cu exhibited a high specific capacitance of 1860 F g-1 at 1 A g-1, and good cycling performance, with an 86.5% capacitance retention after 10 000 cycles. When tested in a two-electrode system, an asymmetric supercapacitor exhibited an energy density of 147.9 W h kg-1 and a power density of 37.0 kW kg-1. These results open a new area of ultrahigh-performance supercapacitors, supported by 3D-Cu electrodes.

Nickel Hydroxide Supercapacitor with a Theoretical Capacitance and High Rate Capability Based on Hollow Dendritic 3D-Nickel Current Collectors.

A straightforward way to attain the theoretical capacitance and high rate capability of nickel hydroxide supercapacitors, by utilizing a mesoporous hollow dendritic three-dimensional-nickel (3D-Ni) current collector is proposed. A facile electrodeposition method employing a hydrogen bubble template was chosen for rapid fabrication of the dendritic 3D-nickel structure. After nickel hydroxide was deposited on the hollow 3D-nickel current collector, it exhibited a highest capacitance of 3637 F g-1 at a current density of 1 A g-1 , and retained 97 % of capacitance at a high current density of 100 A g-1 with a cycle stability of over 80 % after 10 000 cycles. The enhanced performance could be attributed to the large surface area and high conductivity of the moss-like dendritic 3D-Ni current collector, which allowed direct contact between the active materials and the current collector, and reduced diffusion resistance between the surface of the active materials and the electrolyte. These results not only confirmed a facile fabrication method for high-performance 3D metal nanostructures, but also offer a promising solution for state-of-the-art energy storage systems.

p-Doped three-dimensional graphene nano-networks superior to platinum as a counter electrode for dye-sensitized solar cells.

We report CVD-grown p-doped three-dimensional graphene nano-networks (3D-GNs) that provide superior performance to Pt as a counter electrode material in dye sensitized solar cells (DSSCs). The 3D-GN based DSSC exhibits a maximum photoconversion efficiency of 8.46%, which is 6.01% greater than that exhibited by Pt based DSSCs.