Copper Substrate Research Articles

Numerical performance investigation of High Vacuum Flat Plate Hybrid Photovoltaic-Thermal devices.

We propose an innovative flat plate hybrid Photovoltaic-Thermal system under high vacuum (HV PV-T) optimized for solar-to-thermal energy conversion. It consists of a glass cover, metallic vessel, and the actual PV-T device, which englobes a low-emissive Transparent Conductive Oxide (TCO), a perovskite-based PV cell, a Solar Absorber, and a copper substrate. We investigate, through a 1-D model developed in MATLAB, the performances of the proposed PV-T system, still mined by radiative losses, varying the operating temperature (Top) and the emittance of the TCO (εTCO ) in the ranges of (25÷175) °C and (0.05÷0.45) respectively. The annual thermal and electrical productions are evaluated considering the Typical Meteorological Year of Naples, Italy. Specific annual costs and emission savings are evaluated and compared with the ones assured by commercial High Vacuum Flat Plate Solar-Thermal (HVFP ST) and PV collectors. Results indicate that the proposed HV PV-T increases the annual cost savings by 34% and 11% when compared to HVFP ST and PV collectors, respectively. Moreover, the presented HV PV-T increases the annual CO2 emissions savings by 7% and 48% when compared to HVFP ST and PV collectors, respectively.

EXPERIMENTAL STUDY OF CONDENSATION OF WATER ON POLYDIMETHYLSILOXANE-COATED COPPER SURFACES

Modification of surfaces to enable dropwise condensation (DWC) is a promising approach for achieving high condensation rates. In this work, we present an experimental study on condensation of water on copper surfaces coated with an ultrathin, 5-10 nm thick polydimethylsiloxane (PDMS) layer. This hydrophobic coating possesses a very low thermal resistance, which in combination with copper substrate enables achieving high condensation rates in heat transfer applications. The PDMS-coated copper substrates have been fabricated with a newly developed method, which involves turning, sanding, polishing, oxidation, and polymer coating steps. The measured static contact angle was 110° ± 1°, and the contact angle hysteresis was 2°. The achieved very low hysteresis is advantageous for promoting DWC. The surface showed no aging effects during 100 repetitions of advancing and receding contact angle (ARCA) measurements. Condensation heat transfer on uncoated and PDMS-coated copper surfaces surfaces has been studied experimentally in a saturated water vapor atmosphere at 60°C. An enhancement factor for heat flux and heat transfer coefficient of up to 1.6 was found on PDMS-coated copper surfaces compared to uncoated surfaces, which decreased to 1.1 on the second and third day of condensation operation. Images of the condensation surface were recorded while conducting condensation experiments and post processed to evaluate drop departure diameter and frequency of drop sweeping events. It has been shown that the behavior of the heat transfer coefficient correlates with the frequency of the sweeping events.

Research of joining the SiC and Cu combination by use of SnTi solder filled with SiC nanoparticles and with active ultrasound assistance

<p>The aim of this study was to characterize a Sn-Ti solder alloy containing 6 wt.% SiC nanoparticles and evaluate its use for direct soldering of SiC ceramics to a copper (Cu) substrate. Soldering was performed with direct ultrasound activation. The average tensile strength of the solder alloy was 17.1 MPa. Differential Thermal Analysis (DTA) analysis revealed an apparent transition at 234 ℃, corresponding to a eutectic reaction within the Sn-Ti binary system, indicating structural changes in the solder. The solder matrix consisted primarily of pure tin, while titanium combined with SiC nanoparticles to form a TiC phase. The existence of this phase was confirmed by energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) analysis of the solder. The bond at the interface between the SiC ceramic substrate and the solder was formed through diffusion and chemical reactions. The XRD analysis of the fractured surface from the SiC side confirmed the formation of phases such as TiC, Ti<sub>2</sub>Sn, CTi<sub>2</sub>, CuSn, SiC, and Cu<sub>6</sub>Sn<sub>5</sub>; the TiC and CTi<sub>2</sub> phases resulted from the interaction of active Ti in the solder with the SiC ceramic surface. The bond at the Cu substrate interface formed due to the high solubility of tin in the solder and the formation of probable CuSnTi and CuSnTi3<sub>5</sub> phases, along with a mixture of Sn + η Cu<sub>6</sub>Sn<sub>5</sub> solid solution. The average shear strength of the SiC/Cu joint, fabricated using SnTi3 solder with 6 wt.% SiC nanoparticles, was 21.5 MPa.</p>

Simulation of Plasmonic Effects in Nanostructured Copper Surfaces for Field-assisted Photoemission

Plasmonics in photoemission have recently gained interest due to their effect on important electron beam parameters such as emittance or quantum efficiency (QE), among others. For example, the presence of nanostructures at the surface of the photoemissive medium can increase the probability of electron emission if their morphological features match that of the plasmonic resonance when laser-irradiated in an electron gun. To determine the optimal size and geometry of these nanostructures and predict the resulting field enhancement, we conducted parametric electromagnetic simulations of nanostructured surfaces using COMSOL®. We investigated several types of geometries commonly found in laser processed copper substrates, optimized their performance under different irradiation wavelengths, and determined the expected maximal enhancement factor attainable.

Nanocomposites based on Cu2O coated silver nanowire networks for high-performance oxygen evolution reaction.

The development of highly active, low-cost, and robust electrocatalysts for the oxygen evolution reaction (OER) is a crucial endeavor for the clean and economically viable production of hydrogen via electrochemical water splitting. Herein, cuprous oxide (Cu2O) thin films are deposited on silver nanowire (AgNW) networks by atmospheric-pressure spatial atomic layer deposition (AP-SALD). AgNW@Cu2O nanocomposites supported on conductive copper electrodes exhibited superior OER activity as compared to bare copper substrate and bare AgNWs. Moreover, a relationship between Cu2O thickness and OER activity was established. Notably, the most effective catalyst (AgNW@50nm-thick Cu2O) demonstrated very high OER activity with a low overpotential of 409 mV to deliver a current density of 10 mA cm-2 (η 10), a Tafel slope of 47 mV dec-1, a turnover frequency (TOF) of 4.2 s-1 at 350 mV, and good durability in alkaline media (1 M KOH). This highlights the potential of AgNWs as a powerful platform for the formation of highly efficient copper oxide catalysts towards OER. This work provides a foundation for the development of nanostructured Cu-based electrocatalysts for future clean energy conversion and storage systems.

Novel direct synthetic route of 2D Prussian Blue analogue, nanocrystalline CuHCF, as highly effective cathode materials for Zn-ion supercapacitors

Prussian blue analogues (PBAs) with 2D morphology of nanocrystals have attracted much attention for aqueous electrolyte-based energy storage devices. In this study, we synthesized a 2D Prussian blue analogue, nanocrystals of copper hexacyanoferrate (CuHCF), via a facile stepwise route involving a modified copper substrate of Cu(OH)2 nanorods that was used for the formation of two-dimensional CuHCF crystals. These materials were characterized by powder X-ray diffraction, energy dispersive X-ray microanalysis, X-ray photoelectron spectroscopy and scanning electron microscopy. The cathode based on 2D CuHCF exhibits high specific capacity (240 F/g (63.9 mAh/g) at 0.1 A/g) with excellent cycling stability (98.5% retention after 1000 charge-discharge cycles) in 3 M ZnSO4 electrolyte. The flat two-dimensional morphology of CuHCF provides sufficient ion diffusion channels and the numerous electroactive interfaces for intercalation charge storage.

Effect of thermal cycling on microstructure and adhesion properties of Ti-Zr-V thin films

Non-evaporable getter films are essential to obtain the ultra-high vacuum environments for the modern accelerators. However, regular thermal activation of the NEG films is required to maintain their pumping capacity. The thermal activation rises the risk of deteriorating the film/substrate adhesion, which, unfortunately, has been overlooked. In the present work, ternary Ti-Zr-V films were deposited by DC magnetron sputtering on oxygen free copper (OFC) and Si substrates. The effect of thermal cycling on the microstructure and adhesion strength of the thin films were characterized. The results indicate that thermal cycling induce an increased surface roughness due to coarsening of the particle size. Contrary effect is imposed on the adhesion strength of the NEG film deposited on the OFC substrate as compared with that on the Si substrate. After thermal cycling, the scratching critical load of the Ti-Zr-V film on OFC decreases from 0.14 N to 0.06 N while those on Si substrate increased by tenfold from 0.56 N to 5.79 N. The current work is insightful on long-term maintenance of the NEG coated chambers from an angle different from the commonly emphasized pumping capabilities.

Pulse electrodeposition of a duplex-layer structured composite nickel-based coating with improved corrosion and abrasion resistance

In this study, a dual amorphous/crystalline nanocomposite coating of Ni–P/Ni–Mo–ZrO2 was designed and successfully deposited on pure copper substrates by pulse electrodeposition. The design of the Ni–P/Ni–Mo–ZrO2 dual coating takes advantage of the properties of the different structures and incorporates second phase reinforcing particles resulting in more comprehensive protective coatings. The surface morphology and microstructure were evaluated by SEM, EDS, WLI, XRD and TEM. The mechanical properties and electrochemical behaviors of the coating in a 3.5 wt% NaCl solution were investigated by wear tests, Tafel and EIS. The results show that the Ni–P/Ni–Mo and Ni–P/Ni–Mo–ZrO2 dual coatings are uniform, dense and crack-free, and the duplex interface is homogeneous. Compared with the Ni–Mo coating, the average friction coefficient and wear rate of the Ni–P/Ni–Mo duplex coating decreased to 0.18 and 5.433 × 10−4 mm3/N·m, respectively. The corrosion potential is positively shifted to −0.43 with a maximum impedance of 308 kΩ cm2. The mismatch of the interlayer defects causes a deviation in the corrosion path, resulting in a transformation from longitudinal pinhole corrosion into extended transverse corrosion, which effectively strengthens the capacity of the coating for corrosion resistance while maintaining the high hardness of its outer coating. Furthermore, the hardness of the dual Ni–P/Ni–Mo coating can be obviously reinforced by nanoparticles from 730 HV to 810 HV, the corrosion potential is shifted to −0.41 V, and the corrosion current density decrease to 7.7803 × 10−7 A/cm2. The improvement in the mechanical properties can be attributed to the ZrO2 nanoparticles, which could carry stress and transfer loads during the wear process. Meanwhile, the ZrO2 nanoparticles can reduce the nodule size by filling the binding boundary which is the main corrosion path, and reduce the number of surface defects, such as pinholes, which leads to a lower corrosion rate. In addition, the corrosion inhibition and nanoparticle codeposition mechanisms of the duplex coatings were further discussed.

A flat radiative cooling thermoelectric generator for high performance power generation

Thermoelectric generators (TEGs) based on radiative cooling have attracted significant attention in the energy conversion field because they are energy-independent and pollution-free. However, the development of a thin TEG with high and stable output power is still a challenge. Herein, we demonstrate a flat TEG based on radiative cooling, non-radiative heat transfer cooling, and building waste heat. The flat structure of the designed TEG is thin and enables the non-radiative heat transfer to contribute to the cold end of TEG. A porous Poly(vinylidene fluoride-co-hexafluoropropylene) film, adhered to a copper substrate, is prepared by non-solvent-induced phase separation as the radiative cooling emitter (RCE). The temperature of RCE is 19.9 °C lower than that of the building. To harvest the building waste heat efficiently, a copper plate is designed as the heat collector, which increases the temperature difference between the two ends of TEG to 228 % with respect to one without the heat collector. The uninterrupted output power of the designed TEG matches well with residential electricity and reaches 153.1 mW/m2, which exceeds most previous works. 95 light emitting diodes are lit up successfully by the designed TEG, which shows great potential in off-grid, continuous power-consumed applications.

A multifunctional metastructure with dual modulation based on gravity and graphene

Tunable metastructur (MS) is popular for research today, but it is complex and difficult to manipulate, so a novel solution has been proposed. In this paper, a MS based on gravitational field and graphene modulation is presented, which can achieve polarization conversion, amplitude modulation, and operating band shift in the range of the gigahertz (GHz) band. The proposed polarization converter (PC) consists of mercury-filled glass cavities, graphene resonators, a copper substrate, and a polyimide dielectric layer. The mercury flows to different parts through the specially designed glass cavities under the effect of the gravitational field, which results in different functions. When the proposed device is not flipped, within 2.53–4.38 GHz (the relative bandwidth is 54.28 %), the linear-polarized electromagnetic wave can be efficiently converted to the circular-polarized ones, whose axial ratio is less than 3 dB. Moreover, when it is flipped, the designed PC can realize the function of cross-polarization conversion and maintain a polarization conversion rate above 90 % in the band of 3.92–7.36 GHz (the relative bandwidth is 60.99 %). The joint tuning of graphene and gravitational field and related parameters are discussed. Moreover, the physics mechanism of the proposed device is explained according to the surface current diagrams. The proposed PC possesses the advantages of broadband, novel tuning, multifunctional modulation, etc. It can be used in the field of communication, electromagnetic countermeasures, and the electromagnetic wave modulation field.

Influence of Lithium Diffusion into Copper Current Collectors on Lithium Electrodeposition in Anode-Free Lithium-Metal Batteries

With increasing demands for lithium-based batteries that have higher energy densities, access to better negative electrode materials becomes crucial. Lithium metal which has a very high theoretical specific capacity, a very low standard potential and a very low density can be considered one of the best negative electrode materials for next-generation lithium-based batteries. In order to fully exploit the merits of lithium metal, a cell configuration in which lithium is directly electrodeposited (and then stripped) on (from) the negative electrode current collector (i.e., copper foil) is essential. Such “anode-material-free” (or ”anode-free”) lithium-metal batteries can have significantly higher gravimetric and volumetric energy densities than conventional graphite-based lithium-ion batteries. However, poor control of the lithium electrodeposition directly on the copper current collector, especially in conventional carbonate electrolytes, limits the development of such batteries. It is therefore essential to improve the understandings of the lithium electrodeposition, especially its nucleation process, and the interactions between lithium and the copper substrate.According to the classical electrodeposition theory, a larger overpotential will lead to a decrease in both the critical free energy for the nucleation and the critical radius of the nuclei, which should facilitate the nucleation process since more clusters can reach the critical radius required to form stable nuclei with a lower energy barrier. The concept was utilized via the application of a potentiostatic nucleation pulse to attain two-dimensional instantaneous lithium nucleation on lithium-metal electrodes in a previous study by Rehnlund et al.[1] Using such a strategy should also provide some insights into the lithium nucleation on copper substrates. In addition, it is also important to consider interactions between lithium and the copper substrate. A study, in which Lv et al.[2] used operando neutron diffraction to track the spatial distribution of lithium during lithium electrodeposition and stripping on copper, revealed that some lithium was actually taken up by the copper substrates most likely via the grain boundaries during the electrodeposition. In other studies by Rehnlund et al., the results also showed that lithium can diffuse into copper and that the effect of this diffusion can be readily seen after electrodepositing a small amount of lithium (as would be the case during the lithium nucleation stage).[3,4] However, the relation between such a lithium diffusion behavior and the lithium nucleation on copper substrates is not clearly studied.With a series of electrodeposition experiments, we demonstrate that it is highly possible that the lithium diffusion into the copper substrate can influence the nucleation process. Due to the presence of such diffusion, small lithium clusters and nuclei may be lost during the nucleation process, which makes it difficult to obtain a larger number of lithium nuclei with a homogeneous distribution on the copper surface. This then leads to inhomogeneous lithium electrodeposits with poor morphologies. It is, however, demonstrated that the nucleation of lithium on copper can be significantly improved if an initial chemical prelithiation of the copper surface is performed. This prelithiation saturates the copper surface with lithium and hence decreases the influence of lithium diffusion via the grain boundaries. In this way, the lithium nucleation can be made to take place more homogenously on the copper surface, especially when a short potentiostatic nucleation pulse that can generate a large number of nuclei is used.[1] D. Rehnlund, C. Ihrfors, J. Maibach, L. Nyholm, Mater. Today 21 (2018) 1010–1018.[2] S. Lv, T. Verhallen, A. Vasileiadis, F. Ooms, Y. Xu, Z. Li, Z. Li, M. Wagemaker, Nat. Commun. 9 (2018) 1–12.[3] D. Rehnlund, F. Lindgren, S. Böhme, T. Nordh, Y. Zou, J. Pettersson, U. Bexell, M. Boman, K. Edström, L. Nyholm, Energy Environ. Sci. 10 (2017) 1350–1357.[4] D. Rehnlund, J. Pettersson, K. Edström, L. Nyholm, ChemistrySelect 3 (2018) 2311–2314.

Micro-Raman for Local Strain Evaluation of GaN LEDs and Si Chips Assembled on Cu Substrates.

Integrated circuits are created by interfacing different materials, semiconductors, and metals, which are appropriately deposited or grown on substrates and layers soldered together. Therefore, the characteristics of starting materials and process temperatures are of great importance, as they can induce residual strains in the final assembly. Identifying and quantifying strain becomes strategically important in optimizing processes to enhance the performance, duration, and reliability of final devices. This work analyzes the thermomechanical local strain of semiconductor materials used to realize LED modules for lighting applications. Gallium Nitride active layers grown on sapphire substrates and Si chips are assembled by soldering with eutectic AuSn on copper substrates and investigated by Raman spectroscopy in a temperature range of -50 to 180 °C. From the Raman mapping of many different samples, it is concluded that one of the leading causes of strain in the GaN layer can be attributed to the differences in the thermal expansion coefficient among the various materials and, above all, among the chip, interconnection material, and substrate. These differences are responsible for forces that slightly bend the chip, causing strain in the GaN layer, which is most compressed in the central region of the chip and slightly stretched in the outer areas.

Localized Electrochemical Deposition Using Copper Pyrophosphate-Based Electrolyte

Additive manufacturing (AM) has gained popularity across various industries due to its cost-effectiveness, low material consumption, and minimal environmental impact. Localized electrochemical deposition (LECD), as one of the AM methods, has the capability to produce microcomponents or structures at an microscale in a specific position as designed, without the need for any mask or support material[1]. By reducing copper ions in the local area according to the position of the micro-wire, 3D structures could be produced. This electrochemical deposition process has a significant advantage in that it is a low-temperature process and has lower costs compared to other processes[2].Using the LECD process, the micrometer of copper columns was conventionally deposited in copper sulfate-based electrolyte[3]. However, this electrolyte has the possibility to cause damage to the metal substrate used as the cathode due to its low pH, resulting in metal dissolution. The utilization of copper pyrophosphate-based electrolyte, which is a solution with a pH close to neutral, can solve this problem. Also, copper pyrophosphate-based electrolyte offers an advantage over conventional alkaline-based electrolytes in that it removes cyanide pollution of the environment and hazards to human health.[4]In this study, the microanode was employed using a platinum wire(100 μm in diameter), while a copper substrate was employed as the cathode in the electrochemical deposition process. The micrometer copper columns were deposited using copper pyrophosphate-based electrolyte by varying the main electrochemical deposition factors, such as applied potential and pulse duty cycle. In addition The surface morphology of the deposited micrometer-scale copper columns was observed through scanning electron microscopy.REFERENCES[1] Suryavanshi, Abhijit P., and Min-Feng Yu. "Probe-based electrochemical fabrication of freestanding Cu nanowire array." Applied Physics Letters 88.8 (2006): 083103.[2] Madden, John D., and Ian W. Hunter. "Three-dimensional microfabrication by localized electrochemical deposition." Journal of microelectromechanical systems 5.1 (1996): 24-32.[3] Lin, J. C., et al. "Localized electrochemical deposition of micrometer copper columns by pulse plating." Electrochimica Acta 55.6 (2010): 1888-1894.[4] Chen, C-C. "A New Process for Cyanide-Free Copper Plating."Electroplating and Pollution Control 23.4 (2003): 10-11.

Electro-Structured Cu Distorted Nanopyramids for Superior Sweat Glucose Sensing

There is a rising global demand for non-invasive glucose monitoring devices, due to an increase in diabetes and its associated health problems. Nanostructures, including needles, fibers, and rods, have drawn considerable attention due to their unique structural-based physical and chemical features in non-enzymatic electrochemical sensing. Copper is a potential candidate for applied research because of its higher electrical conductivity, low cost, and strong reactivity. To create 3-D nano copper structures, researchers have investigated chemical, electrochemical, and hydrothermal techniques. The electrochemical method can better control the formation reaction for these structures. The electrochemical process has better control over the formation reaction for these structures.Distinctive and self-supported copper nanopyramids were electrochemically created on a copper substrate within a few seconds by electrochemical deposition in a one pot synthesis. The SEM image of the constructed nano copper pyramids are shown in figure 1a. The built nano pyramids have a length of ~200 nm. The generated nanostructures display excellent catalytic activity for non-enzymatic glucose sensing. The created nonenzymatic sensor was tested for glucose detection in synthetic sweat and it displayed a linear response in the range of 20 µM- 2000 µM, making it appropriate for practical applications. The chrono amperometry for glucose sensing was performed at 0.5V for 60s. Figure 1b shows the calibration plot for glucose sensing. Linear response for the glucose was observed in the range from 20µM – 2000µM. The device showed a very low interference for uric acid and ascorbic acid. The device is stable upto 60 days, highly reproducible and can be reused upto 5 times. The correlation coefficient was 0.9857 for the linear equation I(μA) = (9.52*10-3) *C (in µM) + 5.065 and a sensitivity of 1.17 nA/(μM-cm2) was observed Figure 1

Electrodeposition of Reactive Aluminum-Nickel Coatings in an AlCl3:[Emim]Cl Ionic Liquid Containing Nickel Nanoparticles

The electrodeposition of reactive aluminum-nickel dispersion coatings was performed by pulsed direct current (PDC) onto copper substrates in the ionic liquid 1.5:1 AlCl3:[EMIm]Cl (1-Ethyl-3-methylimidazolium chloride). A cathodic current density of 15 mA/cm2 was used with two different frequency (f)/duty cycle (r c) combinations, i.e., f= 0.33 Hz/ r c= 0.33 (t on= 1 s, t off= 2 s) and f= 0.05 Hz/ r c= 0.5 (t on= 10 s, t off= 10 s). Several electrochemical techniques like Cyclic Voltammetry, Electrochemical Impedance Spectroscopy and Open Circuit Potential measurements were used besides X-Ray Diffraction, Confocal Microscopy, Scanning Electron Microscopy, Atomic Absorption Spectroscopy and 27Al/1H Nuclear Magnetic Resonance in order to shed more light on the mechanism of Ni particle incorporation into the Al metal matrix. We could show that particle incorporation at the beginning of the deposition mainly takes place via particle adsorption at the substrate. As the thickness of the coating increases, it seems that the main mechanism for particle incorporation is via the reduction of Al2Cl7 - ions adsorbed at the particles surface. Three different Ni NPs concentration were tested in this work: 5, 10 and 20 g/L. Although a considerable high incorporation of Ni NPs has been achieved from the IL electrolyte containing the highest concentration of Ni NPs (i.e. ~ 33 wt.% from a 20 g/L of Ni NPs bath), a high concentration of NPs in the ionic liquid resulted having a negative effect in terms of quality of the coatings, due to local cathodic passivation, or solidification of the electrolyte in a poorly conductive compound. This phenomenon has been related to the increase in viscosity originating from the decrease in rotational mobility of the [EMIm]+ cation, as detected by 1H NMR. Despite this fact, almost equivalent amounts of Ni and Al (Ni ~ 45 wt.% and Al ~ 44 wt.%) have been detected by energy-dispersive X-ray spectroscopy mapping in some areas of the coatings prepared with longer pulse off-time (f = 0.05 Hz, t off= 10 s). Such a layer composition would be convenient for the targeted application. Nevertheless, more studies related to the homogeneity of the deposits, as well as ignition tests, must be performed to evaluate the suitability of the coatings to trigger a self-propagating reaction.

Deep-eutectic solution adding threonine additive associating with supercritical carbon dioxide to enhance zinc electroplating characteristics

Deep-eutectic solvent (DES) was used widely as an eco-friendly and sustainable process in the zinc (Zn) electroplating in this study. Both the conventional and supercritical carbon dioxide (SC-CO2) assisted electroplating processes were employed in the Zn plating on the copper substrate, respectively. Moreover, the effects of ascorbic acid (AA), nicotinic acid (NA) and threonine (Thr) additives were also investigated systematically. The Zn coating In the XRD result, the Zn texture of (0 0 2) and (1 0 1) as the (1 0 0) gradually vanished as the increase of Thr additive. Whether the use of the additives, the hardness of the prepared Zn coating from SC-CO2 assisted process was higher than conventional counterparts by 30 %. Moreover, the corrosion current density from the potentiodynamic polarization curve tended to be more passive by 55 %, manifesting that the AA and NA additives in the SC-CO2 assisted Zn electroplating was better in anticorrosion capability comparing its counterpart without additives. The current efficiency shew SC-CO2 Zn coating with Thr additive could gain a 15 % enhancement in compared to the conventional Thr-free Zn coating, making the coating more noble. Microstructures investigations using SEM showed the absence of cracking on surface. On the cross-sectional examination using TEM, a dual dense and porous layer structure were observed. EDS analysis revealed the Cu ions dissolving in the DES solution and reacted with Zn ions to for Cu-Zn alloy compounds as well as solid solution of Cu in the Zn coating while the TEM-EDS analysis showed the existence of an extraordinary Zn(Cu) and interfacial Cu-Zn alloy dual-layers. The possible ion-diffusion induced by DES mechanism causing this dual-layer and solid solution structure during the electroplating process in the DES electroplating solution was proposed.

Electrochemical Synthesis of Molybdenum Ditelluride (MoTe2) and Its Potential Application as Negative Electrode Material for Sodium Ion Battery

With the rapid expansion in energy demands and depletion of fossil fuel reservoirs, the importance of clean energy production and storage has increased drastically. The renewable energy recourses are cost effective, sustainable and carbon dioxide emission free alternatives. Nevertheless, this energy is not always available and needs to be stored. Lithium-ion batteries (LIBs) are rapidly used in various applications such as powering electronics, electric vehicles and grid energy storage. However, the source of lithium is extremely limited in earth crust, during mining it pollutes the environment and it is costly. Therefore, attention has been shifted towards development of sodium ion batteries (SIBs) which have wide reserves and low precursor cost and thus is considered as an appropriate choice for solar and wind energy development. The prime problem encountered in development of large-scale SIBs is the low effectiveness of appropriate anode material because of large size and sluggish kinetics of Na ions which limits the specific capacity as well as energy density.Metal tellurides have emerged as a promising material for use as negative electrode in sodium-ion batteries due to its unique layered crystal structure, high intrinsic conductivity, and high trap density. Molybdenum ditelluride has more electric conductivity than selenides and sulfides. Other metals except molybdenum in the group takes part in alloying mechanism that leads to higher volume expansion and poor cycling stability.In this study, we describe the synthesis of MoTe2 on copper and aluminium substrate by using predeposited molybdenum and electrodeposited tellurium at relatively low temperature of 450°C. Further we characterized the samples by X-Ray Diffraction, Raman Spectroscopy and Field Emission Scanning Electron Microscope for structural, elemental, and morphological properties, respectively. The synthesized material was used as negative electrode in sodium ion coin cell. The electrochemical performance of the coin cell will be correlated with the structural and electronic property of MoTe2.

Fabrication of Si Anode for Enhancing Electrochemical Performance by Electrodeposition Method

Silicon (Si) is one of the most abundant elements in the earth's crust and is important for the development of semiconductors, solar cells, and lithium ion battery (LIB)electrodes. silicon nanomaterials-based device production is currently hampered by high prices, high material consumption, and very sophisticated procedures of film deposition, including chemical vapour deposition (CVD) and plasma-enhanced chemical vapour deposition (PE-CVD).Future demand will need the development of cost-effective, simple, and high-throughput deposition techniques.moreover A large-scale use of Si anodes in LIB is hindered primarily by two factors: (a) a significant volume change (about 300%) during discharging and (b) the deterioration of silicon after several charging and discharging cycles. By covering silicon nanostructures with carbon nanomaterials that also improve the electrochemical performance of LIBs, these disadvantages may be eliminated. In order to meet all of these requirements, the electrodeposition approach may provide the means to create Si thin films in an aesthetic way. We studied We used water-contaminated BMImTf2N to electrolyze SiNPs on Graphene (Grn) -coated copper substrates at room temperature.SiNPs average 70-90 nanometres (nm). Grn layer on the Cu substrate enhances Si nucleation and prevents oxidation. At 0.5C, the charge capacity was 1350 mAh g-1 and the discharge capacity was 1588 mAh g-1. The columbic process's efficiency increased from 85% to 97% after 100 cycles. Grn's conductivity and volume expansion will boost Si's cycle life. Figure 1

Transparent superhydrophobic coating for copper metal and study of surface morphology and antimicrobial characteristics

Nowadays, copper is a widely used metal worldwide for various applications such as electronic materials, electrical circuits, ornamentals and decorative applications. Copper is widely known for its antimicrobial properties. Despite this fact, it is found to be susceptible to biocorrosion. To protect the copper metal from biocorrosion, hydrophobically modified silica nanoparticles were prepared by the sol gel process. The Prepared sol solution was characterized by Particle size analysis, transmission electron microscopy (TEM) and infrared spectroscopy. Modified silica nanoparticles coated on the copper substrate to obtain superhydrophobic surface. Surface morphology was observed by scanning electron microscopy (SEM), electron dispersive microscopy (EDX) and atomic force microscopy analysis (AFM). Wettability and antimicrobial activity of the copper surface were also studied. The average particle size was found to be 96 nm and the formation of silica nanoparticle in the sol was also confirmed by IR spectra. The Contact angle of coated copper was found 163.3˚compared to 66.6˚ of uncoated copper surface which confirms the superhydrophobic behavior of the coated surface. The presence of nanostructured surfaces was responsible for superhydrophobic behavior which was confirmed by SEM and AFM studies. The coated copper showed excellent antimicrobial characteristics against E-coli.

Boiling Heat Transfer Performance of Pure Water on Binary Oxide-Based Nanoparticles Coatings

Abstract Pool boiling heat transfer performance has been evaluated on a binary oxide based nanoparticles coated surface. Electrophoretic deposition techniques were used for TiO2 and Al2O3 nanoparticles coatings on polished copper substrates. Four different surfaces have been prepared by varying the deposition time 2.5, 5, 10, and 15 min which are referred to in the text as coated surface (CS)#1, CS#2, CS#3, and CS#4, respectively. The surface characteristics like surface roughness, morphology, and wettability have changed after the coating. It has been observed that all the deposited surfaces are hydrophobic, whereas polished copper surfaces are hydrophilic by nature. The boiling heat transfer performance of surface CS#2 is superior to the other three surfaces, while CS#4 is the worst. The highest enhancement in boiling heat transfer coefficient (BHTC) observed for CS#2 is 62.3%, corresponding to a heat flux of ∼220 kW/m2. The coating layer thickness was also observed to be an important parameter, apart from surface roughness, wettability, and morphology, which may be a cause for heat transfer deterioration, if it crosses a limiting value. In this study the limiting value of coating layer thickness discovered ∼15 μm experimentally.