Flexible free-standing graphene-like film electrode for supercapacitors by electrophoretic deposition and electrochemical reduction

Electrophoretic deposition in conjunction with electrochemical reduction was used to make flexible free-standing graphene-like films. Firstly, graphene oxide （GO） film was deposited on graphite substrate by electrophoretic deposition method, and then reduced by subsequent electrochemical reduction of GO to obtain reduced GO （ERGO） film with high electrochemical performance. The morphology, structure and electrochemical performance of the prepared graphene-like film were confirmed by SEM, XRD and FT-IR. These unique materials were found to provide high specific capacitance and good cycling stability. The high specific capacitance of 254 F/g was obtained from cyclic voltammetry measurement at a scan rate of 10 mV/s. When the current density increased to 83.3 A/g, the specific capacitance values still remained 132 F/g. Meanwhile, the high powder density of 39.1 kW/kg was measured at energy density of 11.8 W-h/kg in 1 mol/L H2SO4 solution. Furthermore, at a constant scan rate of 50 mV/s, 97.02% of its capacitance was retained for 1000 cycles. These promising results were attributed to the unique assembly structure of graphene film and low contact resistance, which indicated their potential application to electrochemical capacitors.

Preparation of YBa_2Cu_3O_(7-δ) superconducting thick film on Ni-W tapes via electrophoretic deposition

The preparation of La0.4Sr0.6TiO3 （LSTO） buffer layer and YBa2Cu3O7-δ（YBCO） superconducting thick film by a low cost technology was studied. The crystal orientation of LSTO and YBCO films was detected by X-ray diffraction, the conductivity of LSTO film and superconductivity of YBCO coating were investigated by standard four-probe method. Excellent in-plane alignment, smooth and dense LSTO buffer layer was successfully prepared on textured Ni-W taps by metal organic deposition （MOD）. YBCO thick film was fabricated by electrophoretic deposition （EPD）. The effects of applied voltage and deposition time on the YBCO coatings properties were studied. The results show that the critical current density of the YBCO coating deposited under 138 V for 35 min was about 600 A/cm2 （0 T, 77 K）.

Electrophoretic deposition of hybrid organic-inorganic PTFE/Al/CuO energetic film

Thermite films are typical energetic materials(EMs)and have great value in initiating explosive devices.However,research in thermite film preparation is far behind that of research in thermite powders.Electrophoretic deposition(EPD)is an emerging,rapid coating method for film fabrication,including of energetic composite films.In this work,a polytetrafluoroethylene(PTFE)/Al/CuO organic-inorganic hybrid energetic film was successfully obtained using the above method for the first time.The addition of lithocholic acid as a surfactant into the electroplating suspension enabled PTFE to be charged.The combustion and energy release were analyzed by means of a high-speed camera and differential scanning calorimetery(DSC).It was found that the combustion process and energy release of PTFE/Al/CuO were much better than that of Al/CuO.The main reason for the excellent combustion performance of the hybrid PTFE/Al/CuO system was that the oxidability of PTFE accelerated the redox reaction between Al and CuO.The prepared PTFE/Al/CuO film was also employed as ignition material to fire a B-KNO_3 explosive successfully,indicating considerable potential for use as an ignition material in micro-ignitors.This study sheds light on the preparation of fluoropolymer-containing organic-inorganic hybrid energetic films by one-step electrophoretic deposition.

Micro arc oxidation and electrophoretic deposition effect on damping and sound transmission characteristics of AZ31B magnesium Alloy

Micro arc oxidation(MAO) and electrophoretic deposition(EPD) process are employed to fabricate a dense coating on magnesium alloy to protect it from corrosion in engineering application. The EPD film changes the damping characteristic of magnesium alloy, and both the MAO and EPD process change the bending stiffness of samples being treated. Damping loss factor(DLF) test and sound transmission experiments were carried out for AZ31 B magnesium alloy with coating fabricated by MAO and EPD processes. The results indicate that DLF is improved in frequency range from 0-850 Hz. Bending stiffness of the samples is improved with MAO and EPD treatment. As a result, the sound transmission loss(LST) is improved in the stiffness control stage of the sound transmission verse frequency curve. To the samples by electrophoresis process, the LST is improved in frequency range from 2500-3200 Hz, because the damping loss factor is improved with EPD process. The results are useful for the surface treatment to enhance the damping loss factor, LST and widespread application of magnesium alloy while improving the corrosion resistance.

Optimizing electrophoretic deposition conditions for enhancement in electrical conductivity of carbon fiber/carbon nanotube/epoxy hybrid composites

The effectiveness of optimizing electrical conductivity of carbon fiber/carbon nanotube （CNT）/epoxy hybrid composites via Taguchi method was demonstrated. CNTs were induced on carbon fabric by electrophoretic deposition （EPD） technique. The essential deposition parameters were identified as l） the deposition time, 2） the deposition voltage, 3） the mass fraction of CNTs in suspension, and 4） the distance between the electrodes. An experimental design was then performed to establish the appropriate levels for each factor. An orthogonal array of L9 （34） was designed to conduct the experiments. Electrical conductivity results were collected as the response. The relative influences of design parameters on the response were discussed. Using the model, signal to noise （S/N） ratio and response characteristics for the optimized deposition parameter combination were predicted. The results show clearly that the optimum condition of electrophoretic deposition （EPD） process improves the electrical conductivity of carbon/epoxy hybrid composites.

High specific strength MWCNTs/Mg-14Li-1Al composite prepared by electrophoretic deposition, friction stir processing and cold rolling

Multi-wall carbon nanotubes reinforced Mg-14Li-1Al composite(MWCNTs/Mg-14Li-1Al) was prepared by the processes of electrophoretic deposition, friction stir processing, and cold rolling. The microstructure and mechanical properties of the composite were investigated. The results show that, the microhardness of the composite is up to HV 84.4, which is 91.38% higher than that of the as-cast matrix alloy(HV 44.1). The yield strength and ultimate tensile strength of the composite are 259 and 313 MPa, which are 135.45% and 115.86% higher than those of the as-cast matrix alloy, respectively, and a high specific strength of 221.98 k N·m/kg is obtained. In the composite, the MWCNTs serve as nucleation particles during the friction stir processing and cold rolling, causing dynamic recrystallization and grain refinement. Furthermore, MWCNTs hinder the movement of dislocations and transfer the load from the matrix alloy, thus improving the strength.

Cathodic electrophoretic deposition of α-Fe_2O_3 coating

Submicro α-Fe2O3 coatings were formed using electrophoretic deposition(EPD) technique in aqueous media. The zeta potentials of different α-Fe2O3 suspensions with different additives were measured as a function of p H to identify the optimum suspension condition for deposition. Electrophoretic depositions of α-Fe2O3 coatings under different applied electric fields and deposition time were studied and the effects of applied voltages and deposition time on deposition rates and thicknesses were investigated. The particle packing densities of the deposits at various applied voltages and deposition time were also analyzed by a scanning electron microscope(SEM). The results show that crack-free α-Fe2O3 coatings with uniform microstructure and good adherence to the nickel substrates are successfully obtained. Electrophoretic deposited α-Fe2O3 coating from aqueous suspension is a feasible, low-cost and environmental friendly method.

Effect of TbF_(3)diffusion on the demagnetization behavior and domain evolution of sintered Nd-Fe-B magnets by electrophoretic deposition

We studied the magnetic properties and domain evolution of annealed and TbF3-diffused sintered Nd-Fe-B magnets using the electrophoretic deposition method.After TbF_(3)diffusion,the coercivity increased significantly by 9.9 kOe and microstructural analysis suggested that Tb favored the formation of the(Nd,Tb)_(2)Fe_(14)B shell phase in the outer region of the matrix grains.The first magnetization reversal and the dynamic successive domain propagation process were detected with a magneto-optical Kerr microscope.For the TbF_(3)-diffused magnet,the magnetization reversal appeared at a larger applied field and the degree of simultaneous magnetization reversal decreased compared with an annealed magnet.During demagnetization after full magnetization,the occurrence of domain wall motion(DWM)in the reproduced multi-domain regions was observed by the step method.The maximum polarization change resulting from the reproduced DWM was inversely related to the coercivity.The increased coercivity for the diffused magnet was mainly attributed to the more difficult nucleation of the magnetic reversed region owing to the improved magneto-crystalline anisotropy field as a result of Tb diffusion.

Electrophoretic Deposition of Hydroxyapatite Coating

Hydroxyapatite (HAP) coatings were deposited onto titanium substrates by electrophoretic deposition (EPD) fromethanol. The results indicated that the addition of very small amount of HCI resulted in a decrease in the aging timeas well as the suspension concentration required to obtain a coating. In addition, the results revealed the existenceof a critical saturated voltage (Vsat), which had significant effect on the quality of deposition. The mean interfacialshear strengths of HAP coatings after sintering were found to be greater than 13 MPa.

Electrophoretic Deposition of TiO2/Nb2O5 Composite Electrode Thin Films for Photovoltaic Application

Nano sized powders of TiO2 （titanium dioxide） and Nb2O5 （Niobium （V） oxide） were used to fabricate TiO2/Nb2O5 composites thin films by EPD （electrophoretic deposition） technique. The metal oxide powders, together with magnesium nitrate hexahydrate pellets, were suspended in propan-2-ol inside an EPD cell. The electrodes, placed 1.2 cm apart, were partially immersed in the suspension and a DC potential applied across them. Key EPD process parameters, which include applied DC electric field, deposition time and solid concentration in suspension, were optimized through visual inspection and from UV-Vis-NIR spectrophotometer spectra. The highest （55%） transmittance was obtained for films with deposition time of 90 s, powder concentration of 0.01 g/40 mL, and 35 V DC （direct current） voltage. XRD micrographs confirmed that TiO2 and Nb2O5 particles were presented in the composite film. SEM （scanning electron microscope） micrographs of the composite electrode thin films showed that porous films of high quality with well controlled morphology were deposited by using the EPD technique.

Effects of Carbon Nanotubes by Electrophoretic Deposition on Interlaminar Properties of Two Dimensional Carbon/carbon Composites

Carbon nanotubes（CNTs） were deposited uniformly on carbon cloth by electrophoretic deposition（EPD）. Thereafter, CNT-doped clothes were stacked and densified by pyrocarbon via chemical vapor infiltration to fabricate two-dimensional（2 D） carbon/carbon（C/C） composites. Effects of EPD CNTs on interlaminar shear performance and mode Ⅱ interlaminar fracture toughness（GⅡc） of 2 D C/C composites were investigated. Results showed that EPD CNTs were uniformly covered on carbon fibers, acting as a porous coating. Such a CNT coating can obviously enhance the interlaminar shear strength and GⅡc of 2 D C/C composites. With increaing EPD CNTs, the interlaminar shear strength and GⅡc of 2 D C/C composites increase greatly and then decrease, both of which run up to their maximum values, i e, 13.6 MPa and 436.0 J·m-2, when the content of EPD CNTs is 0.54 wt%, 2.27 and 1.45 times of the baseline. Such improvements in interlaminar performance of 2 D C/C composites are mainly beneficial from their increased cohesion of interlaminar matrix, which is caused not only by the direct reinforcing effect of EPD CNT network but also by the capacity of EPD CNTs to refine pyrocarbon matrix and induce multilayered microstructures that greatly increase the crack propagation resistance through ＂crack-blocking and-deflecting mechanisms＂.

Increasing the Tensile Property of Unidirectional Carbon/Carbon Composites by Grafting Carbon Nanotubes onto Carbon Fibers by Electrophoretic Deposition

Although in-situ growing carbon nanotubes （CNTs） on carbon fibers could greatly increase the matrix-dominated mechanical properties of carbon/carbon composites （C/Cs）, it always decreased the tensile strength of carbon fibers. In this work, CNTs were introduced into unidirectional carbon fiber （CF） preforms by electrophoretic deposition （EPD） and they were used to reinforce C/Cs. Effects of the content of CNTs introduced by EPD on tensile property of unidirectional C/Cs were investigated. Results demonstrated that EPD could be used as a simple and efficient method to fabricate carbon nanotube reinforced C/Cs （CNT-C/Cs） with excellent tensile strength, which pays a meaningful way to maximize the global performance of CNT-C/Cs.

Electrophoretic deposition of graphene-based materials:A review of materials and their applications

Recently,graphene-based materials have been successfully fabricated by the electrophoretic deposition(EPD)technique and exhibited various extraordinary properties.Here,research progress of the field of graphene-based materials prepared by the EPD process in recent 5 years is reviewed,including graphene films,graphene/non-metal composites,graphene/metal-based nanoparticles composites,graphene/polymer composites.We also summarize the experimental deposition conditions and the applications of the deposited graphene-based materials that have been reported.It can be concluded that EPD is a simple and reliable manipulation technique and promises a bright future for the production of graphenebased materials in the field of advanced nanocomposite materials.Finally the current issues and outlook of the development direction of EPD in future are also proposed.

Effect of gadolinium doping on phase transformation and microstructure of Gd_2O_3-Y_2O_3-ZrO_2 composite coatings prepared by electrophoretic deposition

4 mol.% Y203 stabilized ZrO2 （YSZ） doped with various quantifies of Gd203 （G-YSZ） ceramic comings were synthesized by electrophoretic deposition method, and followed by vacuum sintering and isothermally annealing at 1000 ℃ for different durations. X-ray diffraction （XRD） was used to investigate their phase composition. Scanning electron microscopy （SEM） was employed to examine their microstructure, while energy dispersive X-ray spectrometer （EDS） was used to assess composition of the composite coatings. The results indicated that YSZ coating was composed of tetragonal and monoclinic phase after vacuum sintefing at 1000 ~C for 2 h under vacuum （〈103 Pa）. G-YSZ composite coatings were composed of tetmgonal, monoclinic phase and a small amount of Gd2Zr207 phase after vacuum sintering at 1000 ℃ for 2 h, whereas the content ofmonoclinic phase in G-YSZ composite coatings in- creased with increasing Gd203 concentration. It was found that G-YSZ composite coatings were composed of tetragonal ZrO2 phase, monoclinic ZrO2 phase and cubic phase, whereas Gd2Zr207 phase disappeared, after G-YSZ composite coatings were isothermally annealed at 1000 ℃ in air for 100 h. A detailed description of the results and their discussion was presented in the paper.

Electrophoretic deposition of a supercapacitor electrode of activated carbon onto an indium-tin-oxide substrate using ethyl cellulose as a binder

A transparent energy storage device is an essential component for transparent electronics.The increasing demand for high-power devices stimulates the development of transparent supercapacitors with high power density.A transparent electrode for such supercapacitors can be assembled via the electrophoretic deposition of an active material powder with a binder onto a transparent substrate.The properties of the binder critically influence the electrochemical behavior and performance of the resulting electrode.Ethyl cellulose(EC)is known as an eco-friendly,transparent,flexible,and inexpensive material.Here,we fabricated an electrode film with EC binder via electrophoretic deposition on an indium tin oxide(ITO)substrate instead of using the conventional polytetrafluoroethylene(PTFE)binder.The assembled electrodes with EC and PTFE were compared to investigate the feasibility of EC as a binder from different perspectives,including homogeneity,wettability,electrochemical behavior,and mechanical stability.The EC enabled the formation of a homogeneous film composed of smaller particles and with a higher specific capacitance compared with films prepared with PTFE.The annealing improved the adhesion strength of the EC because of its glass transition;however,its hydrophobic nature limited utilization of the active material for charge storage.Subsequent electrochemical activation improved the wettability of the electrode,resulting in an increased capacitance of 60 F g^(-1).Furthermore,even with the lower wettability of EC compared with that of PTFE,better rate performance was possible with the EC electrode.The increased mechanical stability after the annealing process ensured an excellent cycle life of 95%capacitance retention for 15,000 cycles.

Preparation of Oriented Barium Titanate Thin Films by Combination of Electrophoretic Deposition with Hydrothermal Treatment

Highly oriented barium titanate （BaTiO 3） thin films on Pt substrate were fabricated by combination of electrophoretic deposition with hydrothermal treatment.The structure and morphology of thin films were characterized by X-ray diffraction and field-emission scanning electron microscopy.It is found that the titania precursor film,Ba（OH）2 concentration and hydrothermal temperature play crucial roles in the film morphology and orientation.The BaTiO3 thin films with highly （110） preferred orientation can be formed on polycrystalline Pt substrate by appropriate adjustment of the reaction conditions.The orientation parameter f of highly oriented BaTiO3 films was up to 1.00.The films exhibited a smooth and crack-free surface and remained in the layered structure.In situ topotactic transformation and dissolution-crystallization mechanisms were proposed to explain the morphology and orientation of BaTiO3 films during hydrothermal treatment.

Template-based growth of titanium dioxide nanorods by a particulate sol-electrophoretic deposition process

TiO2 nanorods have been successfully grown into a track-etched polycarbonate （PC） membrane by a particulate sol-electrophoretic deposition from an aqueous medium. The prepared sols had a narrow particle size distribution around 17 nm and excellent stability against aging, with zeta potentials in the range of 47-50 mV at pH 2. It was found that TiO2 nanorods were grown from dilute aqueous sol with a low, 0.1-M concentration. Fourier transform infrared spectroscopy （FT-IR） analysis confirmed that a full conversion of titanium isopropoxide was obtained by hydrolysis, resulting in the formation of TiO2 particles. X-ray diffraction （XRD） results revealed that TiO2 nanorods dried at 100℃ were a mixture of anatase and brookite phases, whereas they were a mixture of anatase and futile structures at 500℃. Moreover, the rutile content of the TiO2 nanorods was higher than that of TiO2 powders. Transmission electron microscope （TEM） images confirmed that TiO2 nanorods had a smooth morphology and longi- tudinal uniformity in diameter. Field emission scanning electron microscope （FE-SEM） images showed that TiO2 nanorods grown by sol-electrophoresis from the dilute aqueous sol had a dense structure with a uniform diameter of 200 rim, containing small particles with an average size of 15 nm. Simultaneous differential thermal （SDT） analysis verified that individual TiO2 nanorods, grown into a PC template, were obtained after annealing at 500℃. Based on kinetic studies, it was found that uniform TiO2 nanorods with high-quality morphology were obtained under optimum conditions at an applied potential of 0.3 V/cm and a deposition time of 60 min.

Electrophoretic deposition of silk fibroin coatings with pre-defined architecture to facilitate precise control over drug delivery

The therapeutic precision and clinical applicability of drug-eluting coatings can be substantially improved by facilitating tunable drug delivery.However,the design of coatings which allows for precise control over drug release kinetics is still a major challenge.Here,a double-layered silk fibroin(SF)coating system was constructed by sequential electrophoretic deposition.A mixture of dissolved Bombyx mori SF(bmSF)molecules and pre-made bmSF nanospheres at different ratios was deposited as under-layer.Subsequently,this underlayer was covered by a top-layer comprising Antheraea pernyi SF(apSF)molecules(rich in arginylglycylaspartic acid,RGD)to improve the cellular response of the resulting double-layered coatings.Additionally,model drug doxycycline was either pre-mixed with dissolved bmSF molecules or pre-loaded into pre-made bmSF nanospheres at the same amount before their mixing and deposition.The thickness and nanosphere content of the under-layer architecture were proportional to the deposition time and nanosphere concentration in precursor mixtures,respectively.The surface topography,wettability,degradation rate and adhesion strength were comparable within the double-layered coating system.As expected,RGD-rich apSF top-layer improved cell adhesion,spreading and proliferation compared with bmSF top-layer.Furthermore,the amount and duration of drug release increased linearly with increasing nanosphere concentration at fixed deposition time,whereas drug release amount increased linearly with increasing deposition time.These results indicate that the dosage and kinetics of loaded drugs can be quantitatively tailored by altering nanosphere concentration and deposition time as main processing parameters.Overall,this study illustrates the strong potential of pre-defining coating architecture to facilitate control over drug delivery.

Electrophoretic deposition and an investigation of co-dopants effect on luminescence property of Mg2SiO4:Eu3+phosphors

Forsterite particles doped with europium ions（Eu^（3＋）） were synthesized via a solution combustion method. The effect of co-dopants on photoluminescence intensity was described. Different percentages of calcium（Ca^（2＋））, zinc（Zn^（2＋））, barium（Ba^（2＋）） and strontium（Sr^（2＋）） were added to the Mg2SiO4：Eu^（3＋）host.The synthesized sample was characterized by X-ray diffraction, transmission electron microscopy,scanning electron microscopy, spectrofluorometer and the FTIR spectroscopy. X-ray diffraction（XRD）results revealed that dominant phase was forsterite in all samples. Additionally, a negligible amount of periclase phase was recognized in the samples. The average size of the synthesized particles was less than 200 nm. The presence of co-dopant led to an enhancement in the photoluminescent property of the synthesized samples. The maximum increase in photoluminescence intensity was obtained by Ba^（2＋）ions as a co-dopant. Condensed films of photoluminescence particles were produced by utilizing electrophoresis technique to deposit particles. The results showed that polyvinyl pyrrolidone was the best surface modifier to raise the mass deposition of the samples on the substrate.

Electrophoretic deposition of chitosan-bioglass^(■)-hydroxyapatite-halloysite nanotube composite coating

The composite coatings of chitosan(CS)-bioglass^(■)(BG)-hydroxyapatite(HA)-halloysite nanotube(HNT)were investigated and produced via electrophoretic deposition(EPD)technique.The utilization of CS as a dispersing,blending and charging agent for ceramic particles,including BG,HA and HNT,allowed the formation of CS-BG/HA/HNT composite,functionally graded composite(FGC)and bilayer film containing different layers.The results of scanning electron microscopy(SEM),energy-dispersive spectrometry(EDS),X-ray diffraction(XRD)and Fourier transform infrared spectroscopy(FTIR)illustrate the composite in the form of the optimum distribution of ceramic components in the CS matrix with thickness of 28μm on titanium(Ti)substrate.Electrochemical impedance spectroscopy(EIS)and potentiodynamic polarization tests indicate that the corrosion resistance of the coated sample increases in corrected simulated body fluid(C-SBF)at 37℃.Finally,the apatiteinducing ability of CS-BG-HA-HNT is proved by the formation of carbonated hydroxyapatite particles on composite coating in C-SBF.