NiO nanoparticles supported on graphene 3D network current collector for high-performance electrochemical energy storage

A Porous and Conductive Graphite Nanonetwork Forming on the Surface of KCu7S4 for Energy Storage

A flexible all-solid-state supercapacitor is fabricated by building a layer of porous and conductive nanonetwork on the surface of KCu₇S₄ nanowires supported on the carbon fiber fabric, where the porous and conductive nanonetwork is assembled by graphite nanoparticles. This porous graphite layer plays a key role in providing ion diffusion channels to access the KCu₇S₄ through the pores for electrochemical reactions and forming electron transport pathways from the graphite network to the electronic collector of the carbon fiber fabric. This flexible supercapacitor exhibits excellent electrochemical performance with high specific capacitance of 408 F g^-1 at a current density of 0.5 A g^-1 and high energy density of 36 Wh kg^-1 at a power density of 201 W kg^-1. Moreover, it is cost-effective, easy to scale up and environmentally friendly with high flexibility. Our investigation demonstrates that such a porous and conductive nanonetwork could be used to improve the charge storage efficiency for a wide range of electrode materials.

High Density Arrayed Ni/NiO Core-shell Nanospheres Evenly Distributed on Graphene for Ultrahigh Performance Supercapacitor

A novel NiO/Ni/RGO three-dimensional core-shell architecture consisting of Ni nanoparticles as core, NiO as shell and reduced graphene oxide (RGO) as conductivity layer, has been constructed by redox reactions with hydrothermal method and heat treatment. High density arrayed nickel nanoparticles (20 nm diameter) semi-coated by a 3 nm thick layer of NiO are evenly distributed on the surface of graphene. This elaborate design not only uses abundant NiO surfaces to provide a wealth of active sites, but also bridges electrochemical active NiO shell and graphene by Ni core to construct an interconnected 3D conductive network. Since both electrochemical activity and excellent conductivity are reserved in this Ni/NiO core-shell/graphene layer 3D structure, the as-prepared electrode material exhibits an extremely high specific capacitance (2048.3 F g⁻¹ at current density of 1 A g⁻¹) and excellent cycle stability (77.8% capacitance retention after 10000 cycles at current density of 50 A g⁻¹). The novel method presented here is easy and effective and would provide reference for the preparation of other high performance supercapacitor electrodes.

Highly-Efficient Dendritic Cable Electrodes for Flexible Supercapacitive Fabric

In the search for clothlike wearable energy-storage devices with both high energy density and high power density, metal fibers surrounded by micro metal dendrites, as current collectors, are either rooted inside a thick layer of carbon particles or wrapped with flowerlike nano NiO in a similar manner to the root or stem system of natural plants, to form dendritic cablelike negative or positive electrodes. These dendritic cable electrodes could be further combined or woven into flexible solid-type supercapacitive garland or fabric, together with cotton wires. Benefiting from the ultra large interface of the metal dendrites current collector, it can be charged up to 1.8 V, and give an energy density of 0.1408 mWh cm^-2 and a power density of 3.01 mW cm^-2, which is capable of directly starting a small electric car with a short and flexible piece of supercapacitor.