Fabrication of a low defect density graphene-nickel hydroxide nanosheet hybrid with enhanced electrochemical performance

Abstract

The development of efficient energy storage devices with high capacity and excellent stability is a demanding necessary to satisfy future societal and environmental needs. A hybrid material composed of low defect density graphene-supported Ni(OH) 2 sheets has been fabricated via a soft chemistry route and investigated as an advanced electrochemical pseudocapacitor material. The low defect density graphene effectively prevents the restacking of Ni(OH) 2 nanosheets as well as boosting the conductivity of the hybrid electrodes, giving a dramatic rise in capacity performance of the overall system. Moreover, graphene simultaneously acts as both nucleation center and template for the in situ growth of smooth and large scale Ni(OH) 2 nanosheets. By virtue of the unique two-dimensional nanostructure of graphene, the as-obtained Ni(OH) 2 sheets are closely protected by graphene, effectively suppressing their microstructural degradation during the charge and discharge processes, enabling an enhancement in cycling capability. Electrochemical measurements demonstrated that the specific capacitance of the as-obtained composite is high as 1162.7 F/g at a scan rate of 5 mV/s and 1087.9 F/g at a current density of 1.5 A/g. In addition, there was no marked decrease in capacitance at a current density of 10 A/g after 2000 cycles, suggesting excellent long-term cycling stability.

N-doped graphene as a bifunctional electrocatalyst for oxygen reduction and oxygen evolution reactions in an alkaline electrolyte

“…2 shows the FTIR patterns of the GO and NG samples. The strong absorption peak at high frequency (3390 m À1 ) can be assigned to the OeH stretching vibration of water molecules in the two samples [23]. The peaks at 1715 cm À1 and 1618 cm À1 in the GO sample are attributed to the C]O and OeH vibrations of graphene oxide, respectively [24].…”

Graphene based metal and metal oxide nanocomposites: synthesis, properties and their applications

“…[356][357][358][359] With the combination of layered Ni(OH) 2 and graphene a specific capacitance of 1568 F g -1 at a current density of 4 A g -1 could be achieved. This is significantly higher than that of bare Ni(OH) 2 .…”

Ni@NiO core/shell dendrites for ultra-long cycle life electrochemical energy storage

“…1 Nickel based materials have been identied as promising electrode materials for electrochemical energy storage devices because of their high theoretical specic capacitance ($2584 F g À1 for NiO and 2082 F g À1 for Ni(OH) 2 ), environmental friendliness and low cost. 2,3 With the aim to provide a larger reaction area and shorten ion diffusion paths, many fabrication methods including chemical precipitation, 4,5 hydrothermal synthesis, [6][7][8][9][10][11] sol-gel, 12,13 thermal oxidation [14][15][16] and anodization 17,18 have been used to produce various kinds of nickel-based nanostructures, such as amorphous Ni(OH) 2 nanoboxes, 5 Ni-Co oxide nanowires, 6,19 Ni(OH) 2 nanosheets, 7,11 NiO nanobelts, 8 nanosized rambutan-like NiO, 9 urchin-like NiCo 2 O 4 , 10 spinel nickel cobaltite aerogels, 12 NiO nanoowers, 13 NiO nanoblocks 14 and sponge-like Ni(OH) 2 -NiF 2 composites. 18 Apart from the above methods, electrodeposition has gained more and more attention because the electroactive material can be directly grown on a current collector without the need for using any binder or conducting agent.…”