Solvothermal synthesis of NiAl double hydroxide microspheres on a nickel foam-graphene as an electrode material for pseudo-capacitors

In this paper, we demonstrate excellent pseudo-capacitance behavior of nickel-aluminum double hydroxide microspheres (NiAl DHM) synthesized by a facile solvothermal technique using tertbutanol as a structure-directing agent on nickel foam-graphene (NF-G) current collector as compared to use of nickel foam current collector alone. The structure and surface morphology were studied by X-ray diffraction analysis, Raman spectroscopy and scanning and transmission electron microscopies respectively. NF-G current collector was fabricated by chemical vapor deposition followed by an ex situ coating method of NiAl DHM active material which forms a composite electrode. The pseudocapacitive performance of the composite electrode was investigated by cyclic voltammetry, constant charge–discharge and electrochemical impedance spectroscopy measurements. The composite electrode with the NF-G current collector exhibits an enhanced electrochemical performance due to the presence of the conductive graphene layer on the nickel foam and gives a specific capacitance of 1252 F g−1 at a current density of 1 A g−1 and a capacitive retention of about 97% after 1000 charge–discharge cycles. This shows that these composites are promising electrode materials for energy storage devices

P3HT:PCBM/nickel-aluminum layered double hydroxide-graphene foam composites for supercapacitor electrodes

In this paper, a simple dip-coating technique is used to deposit a P3HT:PCBM/Nickel Aluminum layered double hydroxide-graphene foam (NiAl-LDH-GF) composite onto a nickel foam (NF) serving as a current collector. A self-organization of the polymer chains is assumed on the Ni-foam grid network during the slow “dark” drying process in normal air. Electrochemical cyclic voltammetry (CV) and constant charge-discharge (CD) measurements show an improvement in the supercapacitive behavior of the pristine P3HT:PCBM by an order of magnitude from 0.29 F cm-2 (P3HT:PCBM nanostructures) to 1.22 F cm-2 (P3HT:PCBM/NiAl-LDH-GF composite structure) resulting from the addition of NiAl-LDH-GF material at a current density of 2 mA cm-2. This capacitance retention after cycling at 10 mA cm-2 also demonstrates the electrode material’s potential for supercapacitor applications.South African Research Chairs Initiative (SARChI) of the Department of Science and Technology (DST) and the National Research Foundation (NRF).http://link.springer.com/journal/100082015-08-30hb201