Consecutive layers of Ni(OH) and Co(OH) were electrodeposited on stainless steel current collectors for preparing charge storage electrodes of high specific capacity with potential application in hybrid supercapacitors. Different electrodes were prepared consisting on films of Ni(OH), Co(OH), NiCo(OH) and layered films of Ni(OH) on Co(OH) and Co(OH) on Ni(OH) to highlight the advantages of the new architecture. The microscopy studies revealed the formation of nanosheets in the Co(OH) films and of particles agglomerates in the Ni(OH) films. Important morphological changes were observed in the double hydroxides films and layered films. Film growth by electrodeposition was governed by instantaneous nucleation mechanism. The new architecture composed of Ni(OH) on Co(OH) displayed a redox response characterized by the presence of two peaks in the cyclic voltammograms, arising from redox reactions of the metallic species present in the layered film. These electrodes revealed a specific capacity of 762 C g at the specific current of 1 A g. The hybrid cell using Ni(OH) on Co(OH) as positive electrode and carbon nanofoam paper as negative electrode display specific energies of 101.3 W h g and 37.8 W h g at specific powers of 0.2 W g and 2.45 W g, respectively.
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http://dx.doi.org/10.1038/srep39980 | DOI Listing |
Adv Sci (Weinh)
August 2024
Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang-si, Gyeongsangbuk-do, 37673, Republic of Korea.
Despite the very high theoretical energy density, Li-S batteries still need to fundamentally overcome the sluggish redox kinetics of lithium polysulfides (LiPSs) and low sulfur utilization that limit the practical applications. Here, highly active and stable cathode, nitrogen-doped porous carbon nanotubes (NPCTs) decorated with NiCoS nanocrystals are systematically synthesized as multi-functional electrocatalytic materials. The nitrogen-doped carbon matrix can contribute to the adsorption of LiPSs on heteroatom active sites with buffering space.
View Article and Find Full Text PDFDalton Trans
November 2018
KAUST Catalysis Center and Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
A terminal nickel hydroxide complex (PN3P)Ni(OH) (3) bearing the 2nd generation phosphorus-nitrogen PN3P-pincer ligand has been synthesized and structurally characterized. As a nucleophile, 3 reacts with CO to afford the hydroxycarbonyl complex 4, (PN3P)Ni(COOH). 3 can also activate CO2 and CS2 to produce nickel bicarbonate (PN3P)Ni(OCOOH) (5) and bimetallic dithiocarbonate [(PN3P)NiS]2CO (6) respectively, as well as to promote aryl isocyanate and isothiocyanate insertion into the Ni-OH bond to give the corresponding (PN3P)NiEC(O)NHAr complexes (E = O, 7; E = S, 8).
View Article and Find Full Text PDFCell Biol Toxicol
August 2016
School of Pathology, Department of Molecular Medicine and Haematology, University of the Witwatersrand, P/Bag 3, Wits, 2050, South Africa.
Surface-modified gold nanoparticles (AuNPs) are nanomaterials that hold promise in drug delivery applications. In this study, the cytotoxicity, uptake, intracellular localization, and the exocytosis of citrate-stabilized (Cit-AuNP) and polyethylene glycol (PEG)-modified gold nanoparticles with the carboxyl (COOH) terminal functional group were assessed in human embryonic kidney (HEK 293) and the human caucasian hepatocytes carcinoma (Hep G2) cell systems, representing two major accumulation sites for AuNPs. The zeta (ζ)-potential measurements confirmed the negative surface charge of the AuNPs in water and in cell growth medium.
View Article and Find Full Text PDFPhys Chem Chem Phys
September 2015
Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA.
Infrared vibrational predissociation spectra of transition metal hydroxide clusters, [MOH](+)(H2O)1-4·D2 with M = Mn, Fe, Co, Ni, Cu, and Zn, are presented and analyzed with the aid of density functional theory calculations. For the [MnOH](+), [FeOH](+), [CoOH](+) and [ZnOH](+) species, we find that the first coordination shell contains three water molecules and the four ligands are arranged in a distorted tetrahedral geometry. [CuOH](+) can have either two or three water molecules in the first shell arranged in a planar arrangement, while [NiOH](+) has an octahedral ligand geometry with the first shell likely closed with five water molecules.
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