INVESTIGATION OF SURFACE MORPHOLOGY, STRUCTURE AND ELECTROCATALYTIC PROPERTIES FOR O_2 EVOLUTION OF TITANIUM BASED IrO_2+Ta_2O_5 COATINGS

Titanium based IrO2 +Ta2O5 oxide anodes with different compositions and pyrolysis temperatures were prepared by termodecompoisition method. By using X-ray diffraction (XRD), the structure and texture coefficient of the coatings, TC(hkl), of IrO2 rutile crystal have been tested. It showed that, the crystallization processes of IrO2 and Ta2O5 in xIrO2 +(100-x) Ta2 O5 (x is in mol%) films affected and confined each other.In the mixed system, IrO2 rutile phase existed as a solid solution with Ta, and attained the maximum solubility when x=70mol%, i.e. for the coating of 70% IrO2 +Ta2O5.For the coatings of low iridium content or at low preparing tem pemture, (110) and (101) pwtered orientations were dominant. However, preferred growth of IrO2 weakened with increasing either iridium content or temperature. Three typical surface morphologies were observed by using scanning electron tnicroscopy(SEM). The crystallite size of the mixed oxide coatings were finest for the the film of 70%IrO2 +30%Ta2O5,and decreased with the pyrolysis tempemture. As the results of the finest crystallite segregating on sudece and the maxitnum solid solubility of Ir and Ta component in deposits, the coatings with the composition of 70%IrO2 +Ta2O5 prepared at 450℃ presented the mdrimutn electrocatalgtic activitg for O2 evolution in 0. 5M H2SO4 solution.UP to 550℃, Ti base suffered to oxidation resulting in decreasing anode conductivity,therefore, coatings performed a low activity.

Preparation of Hydroxyapatite-titanium Dioxide Coating on Ti6Al4V Substrates using Hydrothermal-electrochemical Method

Ti6Al4V substrates were anodized in a 0.5 mol/L H_2SO_4 solution at applied voltages of 90-140 V.A hydroxyapatite-titanium oxide（HA-TiO2）coating was then deposited on the anodized Ti6Al4 V substrates via a hydrothermal-electrochemicalmethod at a constant current.The obtained films and coatings were characterized by X-ray diffraction,scanning electron microscopy,energy-dispersive X-ray spectroscopy,and Fourier-transform infrared spectrometry.The microstructures of the porous films on the Ti6Al4 V substrates were studied to investigate the effect of the anodizing voltage on the phase and morphology of the HATiO_2 coating.The results indicated that both the phase composition and the morphology of the coatings were significantly influenced by changes in the anodizing voltage.HA-TiO_2 was directly precipitated onto the surface of the substrate when the applied voltage was between 110 and 140 V.The coatings had a gradient structure and the HA exhibited both needle-like and cotton-like structures.The amount of cotton-like HA structures decreased with an increase in voltage from 90 to 120 V,and then increased slightly when the voltage was higher than 120 V.The orientation index of the（002）plane of the coating was at a minimum when the Ti6Al4 V substrate was pretreated at 120 V.

Properties of Al/Conductive Coating/α-PbO2-CeO2-TiO2/β-PbO2-WC-ZrO2 Composite Anode for Zinc Electrowinning

The properties of Al/conductive coating/α-PbO2-CeO2-TiO2/β-PbO2-WC-ZrO2 composite anode for zinc electrowinning were investigated. The electrochemical performance was studied by Tafel polarization curves（Tafel）, electrochemical impedance spectroscopy（EIS） and corrosion rate obtained in an acidic zinc sulfate electrolyte solution. Scanning electron microscopy（SEM）, X-ray diffraction（XRD）, and energy dispersive X-ray spectroscopy（EDXS） were used to observe the microstructural features of coating. Anodes of Al/conductive coating/α-PbO2-CeO2-TiO2/β-PbO2, Al/conductive coating/α-PbO2-CeO2-TiO2/β-PbO2-WC, Al/conductive coating/α-PbO2-CeO2-TiO2/β-PbO2-ZrO2, and Pb-1%Ag anodes were also researched. The results indicated that the Al/conductive coating/α-PbO2-CeO2-TiO2/β-PbO2-WC-ZrO2 showed the best catalytic activity and corrosion resistant performance; the intensity of diffraction peak exhibited the highest value as well as a new PbWO4 phase; the content of WC and ZrO2 in coating showed the highest value as well as the finest grain size.

Effect of rare earth Eu on anti-passivation of metal oxide anode coating

The anti passivation effect of metal oxide anode coating doped with rare earth element Eu was discussed. The morphology and the composition distribution of the metal oxide coating anode before and after electrolysis were studied by SEM and EDX analyses. The results show that the erosion of the electrolyte at the defects is the main cause for the failure of the coating. The erosion rate of the electrolyte is anisotropic. In area with high density of defects, the erosion rate is very fast and the failure of the coating is very quick. Moreover, the life time of the coating is prolonged by the doping of Eu. [

Adhesion Improvement of Zirconium Coating on Polyurethane Modified by Plasmas

In order to improve the adhesion of the middle frequency magnetic sputtered zirconium coating on a polyurethane film,an anode layer source was used to pretreat the polyurethane film with nitrogen and oxygen ions.SEMs and AFM roughness profiles of treated samples and the contrast groups were obtained.Besides,XPS survey spectrums and high resolution spectrums were also investigated.The adhesion test revealed that ion bombardment could improve the adhesion to the polyurethane coating substrate.A better etching result of oxygen ions versus nitrogen predicts a higher bonding strength of zirconium coating on polyurethane and,indeed,the highest bonding strengths are for oxygen ion bombardment upto 13.3 MPa.As demonstrated in X-ray photoelectron spectroscopy,the oxygen ion also helps to introduce more active groups,and,therefore,it achieves a high value of adhesion strength.

Sub-100 nm hollow SnO_2@C nanoparticles as anode material for lithium ion batteries and significantly enhanced cycle performances

Rational designing and controlling of nanostructures is a key factor in realizing appropriate properties required for the high-performance energy fields. In the present study, hollow Sn O2@C nanoparticles（NPs） with a mean size of 50 nm have been synthesized in large-scale via a facile hydrothermal approach.The morphology and composition of as-obtained products were studied by various characterized techniques. As an anode material for lithium ion batteries（LIBs）, the as-prepared hollow Sn O2@C NPs exhibit significant improvement in cycle performances. The discharge capacity of lithium battery is as high as 370 m Ah g 1, and the current density is 3910 m A g 1（5 C） after 573 cycles. Furthermore, the capacity recovers up to 1100 m Ah g 1at the rate performances in which the current density is recovered to 156.4 m A g 1（0.2 C）. Undoubtedly, sub-100 nm Sn O2@C NPs provide significant improvement to the electrochemical performance of LIBs as superior-anode nanomaterials, and this carbon coating strategy can pave the way for developing high-performance LIBs.

SiO_2@C hollow sphere anodes for lithium-ion batteries

As anode materials for lithium-ion batteries, SiO2 is of great interest because of its high capacity, low cost and environmental affinity. A facile approach has been developed to fabricate SiO2@C hollow spheres by hydrolysis of tetraethyl orthosilicate（TEOS） to form SiO2 shells on organic sphere templates followed by calcinations in air to remove the templates, and then the SiO2 shells are covered by carbon layers.Electron microscopy investigations confirm hollow structure of the SiO2@C. The SiO2@C hollow spheres with different SiO2 contents display gradual increase in specific capacity with discharge/charge cycling,among which the SiO2@C with SiO2 content of 67 wt% exhibits discharge/charge capacities of 653.4/649.6 mAh g^（-1） over 160 cycles at current density of 0.11 mA cm^（-2）. The impedance fitting of the electrochemical impedance spectroscopy shows that the SiO2@C with SiO2 content of 67 wt% has the lowest charge transfer resistance, which indicates that the SiO2@C hollow spheres is promising anode candidate for lithium-ion batteries.

Lithiation-enhanced charge transfer and sliding strength at the silicon-graphene interface:A first-principles study

The application of silicon as ultrahigh capacity electrodes in lithiumion batteries has been limited by a number of mechanical degradation mechanisms including fracture, delamination and plastic ratcheting, as a result of its large volumetric change during lithiation and delithiation. Graphene coating is one feasible technique to mitigate the mechanical degradation of Si anode and improve its conductivity. In this paper, first-principles calculations are performed to study the atomic structure, charge transfer and sliding strength of the interface between lithiated silicon and graphene. Our results show that Li atoms segre- gate at the （lithiated） Si-graphene interface preferentially, donating electrons to graphene and enhancing the interfacial sliding resistance. Moreover, the interfacial cohesion and sliding strength can be further enhanced by introducing single-vacancy defects into graphene. These findings provide insights that can guide the design of stable and efficient anodes of silicon/graphene hybrids for energy storage applications.