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Graphical abstract Highlights • Mo atoms and Al 2 O 3 particles were simultaneously incorporated into Ni coatings. • Mo atoms were dissolved in the Ni structure, forming a Ni-Mo solid solution. • The alumina particles were homogeneously distributed in the coatings. • The properties of deposited coatings were deteriorated at high current densities. • The optimum current density was determined to be 4 A/dm2. Abstract In this study, the effect of deposition current density on the characteristics of nickel-molybdenum/alumina coatings processed by an electrodeposition method was investigated. Morphological, elemental and phase evaluations were conducted on the deposited coatings by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction, respectively. Furthermore, the hardness, wear and corrosion behaviors of the prepared coatings were measured. The results showed that the coatings prepared at high current densities, typically at 8 A/dm2, exhibit a porous and rough morphology. Also, the contents of molybdenum and alumina deposited at high current densities are reduced, thus increasing the crystallite size and deteriorating the mechanical properties and corrosion resistance. In this regard, the optimum current density to meet the most desirable properties was found to be 4 A/dm2. [ABSTRACT FROM AUTHOR]

Nano-sized spherical MnO 2 electrodes were galvanostatically deposited onto graphite substrates at various anodic current densities and they were then subjected to heat treatment at 200 °C for 2 h in air. The structure, morphology and specific surface area of the prepared films were investigated by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FESEM) and nitrogen adsorption-desorption analyses. The pseudocapacitive property of the electrodes was found using cyclic voltammetry, chronopotentiometry and ac impedance measurements. The results revealed that the active surface area and the energy storage performance were enhanced with the increase in the deposition current density. A maximum areal capacitance of 0.42 F cm −2 at 5 mA cm −2 was obtained for the film deposited at 25 mA cm −2 . To further improve the charge storage property, a CNT/MnO 2 composite electrode was fabricated via the electrodeposition of manganese oxide on an as-prepared electrophoretically CNTs-coated graphite substrate. Owing to the good electrical conductivity and unique structure of CNTs, the composite electrode exhibited an optimum areal capacitance of 0.59 F cm −2 at 5 mA cm −2 and superior cycling stability of 93.2% after 1000 cycles at a current rate of 10 mA cm −2 . [ABSTRACT FROM AUTHOR]

In this work, we prepared MnO 2 electrodes by ultrasonic-assisted electrodeposition to study the influence of current density on the surface morphology and electrochemical performances of the MnO 2 , as well as the electrochemical performances of MnO 2 electrodes of supercapacitors and lithium-ion batteries. The prepared MnO 2 electrodes showed nanorod morphology, and the grain size changeed and presented a different distribution at different current densities. The electrochemical performances of as-prepared electrodes under a current density of 7 mA cm−2 shows a high mass specific capacitance of 415.4 F g−1 at the current density of 1 A g−1 in supercapacitors and 818.1 mA h·g−1 at 1 A g−1 after 200 cycles in lithium-ion batteries. • The effect of current density on the morphology and electrochemical properties was studied. • The electrochemical properties of MnO 2 used as electrode material of LIBs and supercapacitors were studied. • Adopting ultrasonic-assisted electrode-deposition makes the film uniform and stable. • MnO 2 for SCs shows 415.4 F g−1 at the current density of 1 A g−1. • MnO 2 for LIBs shows 818.1 mA h·g−1 after 200 cycles at 1 A g−1. [ABSTRACT FROM AUTHOR]

Abstract: Free-standing films of PPy(CF3SO3) were galvanostatically electropolymerised in propylene carbonate on a stainless steel electrode using different deposition current densities. The actuation performance of these films in an aqueous 1.0M NaPF6 electrolyte was investigated by in situ measurements of electrochemomechanical deformation (ECMD) during cyclic voltammetry experiments. The extent of linear strain of the films decreased with a higher deposition current density. X-ray photoelectron spectroscopy was used to estimate the amount of ‘disordered carbon’, carbonyl carbon and the doping level of the films. These values were related to the strain obtained from ECMD measurements. SEM images revealed a denser film morphology for films deposited using a lower current density. [Copyright &y& Elsevier]

To achieve maximum utilization of precious platinum catalyst for ethanol electro-oxidation the highest possible surface to volume ratio of the dispersed metal is desirable. In this respect we have investigated the roughness factor of carbon-supported platinum catalysts prepared at different deposition current densities. It is observed that lowering the deposition current density can considerably reduce platinum particle size and thereby increase the roughness factor of the electrode. Further, use of PTFE in the deposition bath results in highly porous platinum dispersion. The combined effect of these two factors significantly enhances the electrocatalytic activity of platinum catalysts towards ethanol oxidation. Cyclic voltammetry, steady state polarization, and electrochemical impedance spectroscopy are used to investigate the kinetics and mechanism of ethanol electro-oxidation. SEM-EDX analysis has been performed to investigate the morphology and chemical composition of the synthesized catalyst layers. [ABSTRACT FROM AUTHOR]