Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “ELECTRODEPOSITION”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3

Cesium Removal from Surrogate Pyroprocessing Salt by Electrodeposition

Active metals in used nuclear fuel dissolve into the salt during pyroprocessing and are not removed by electrorefining or drawdown operations. The buildup of 137 Cs over time increases the heat load and ionizing radiation level of the salt such that it must be replaced frequently, resulting in a significant amount of salt waste. An effective means of managing cesium in the molten salt electrolyte would increase the efficiency of pyroprocessing and decrease the volume of salt waste requiring disposal. A previous report summarized issues that must be addressed when developing a removal strategy and assessed the suitability of existing methods and remaining technological gaps to their application (Rose and Thomas 2023). Cesium is extremely stable in molten salt as a chloride—even more stable than the LiCl-KCl eutectic base salt used for pyroprocessing fuel—which makes removing cesium a challenge. However, sufficiently strong atomic interactions occur between active metal species and liquid metals that make the electrodeposition of active metal fission products into liquid metal electrodes energetically favorable. The feasibility of recovering cesium from LiCl-KCl pyroprocessing salt through electrodeposition into liquid metals is eing assessed by identifying potentially effective liquid metals and performing tests to determine the effectiveness of electrodepositing cesium from a LiCl/KCl salt into these liquid metals. Previous studies investigating the electrodeposition of Sr 2+ , and Ba 2+ into zinc, cadmium, bismuth, lead, tin and antimony have shown that alkali and alkaline earth metals can be electrodeposited at liquid metal cathodes (Kim et al., 2018). The removal of Ba 2+ and Sr 2+ was measured to be more efficient than the removal of monovalent cations due to the greater thermochemical driving force for alloying those elements with the liquid metal (Jang et al. 2022). Because the equilibrium potentials are dependent on the interactions of the active metal in the liquid metal, it is likely that the other alkali metals Li + , and K + , will deposit from LiCl/KCl salt with the Cs + . Therefore, application of this method to recover active metals from pyroprocessing salt will benefit from the use of a liquid metal and set of operating conditions that sufficiently increase the reduction potential of cesium to remove cesium from the waste salt with an acceptable amount of co-deposited lithium and potassium.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Electrodeposition of near-equiatomic CoCuFeNi multi-principal element alloys from an acidic glycine-citrate-triton X100 aqueous electrolyte

Understanding the composition and morphology control of electrodeposited CoCuFeNi is the first step to finding a general strategy for developing electrodeposition processes of unconventional alloys with large redox potential differences and complicated deposition mechanisms. Here, in this work, we have successfully synthesized the near-equiatomic (<5 at% error) CoCuFeNi films with ~200nm thickness by electrodeposition from glycine-citrate-Triton X-100 acidic electrolytes. This system generally follows the Principle II in Brenner’s paradigm on alloy composition control in electrodeposition. X-ray diffraction (XRD) profiles show that the films only consist of one crystalline phase, different from the deposit from ammonia-citrate-boric acid electrolytes and the equilibrium phases predicted by CALPHAD. The near-equiatomic deposits at Ru substrates were successfully annealed at 400 ° C without significant intermixing between the substrate and the deposit, in which no phase separation of the crystalline phase was observed in its XRD profile. Xray photoelectron spectroscopy (XPS) reveals that some depositing elements (mainly Fe) exist as metal oxides. Cu is dissolved in the crystalline phases, stabilized by small crystalline domain size and the amorphous metal oxides inside the CoCuFeNi deposits.

CoCuFeNi↗

Effect of electrodeposition temperature on grain orientation and corrosion resistance of nanocrystalline pure nickel

The nanocrystalline pure nickels with different grain orientations were fabricated by direct current electrodeposition process. The grain size slightly decreased with the increasing of electrodeposition solution temperature. However, grain orientation was affected significantly. Comparing with samples obtained at 50 °C and 80 °C, sample obtained at 20 °C had the strongest (111) orientation plane which increased electrochemical corrosion resistance of this sample. At the same time, the lowest (111) orientation plane deteriorated electrochemical corrosion resistance of sample obtained at 50 °C. - Graphical abstract: The increased electrodeposition temperature promoted slightly grain refinement. The grain orientation was affected significantly by electrodeposition solution temperature. The (111) orientation plane of sample increased significantly corrosion resistance. Display Omitted.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Compositionally graded Fe{sub (1−x)}-Pt{sub (x)} nanowires produced by alternating current electrodeposition into alumina templates

Fe{sub (1−x)}-Pt{sub (x)} (0<x<1) compositionally graded nanowires (50 nm in diameter and 1 µm in length) were fabricated by alternating current (AC) electrodeposition into nanoporous aluminum oxide templates through a systematic approach. The effect of AC electrodeposition parameters such as frequency, voltage and electrolyte concentration on morphology and chemical composition of Fe-Pt alloy nanowires was studied. Based on experimental data, AC sine wave deposition at an intermediate voltage of 12 V{sub rms} and a frequency of 50 Hz, produces nanowires with nearly stoichiometric composition (Fe{sub 42}Pt{sub 58}) and a reasonably good uniformity of pore filling. However, there is a gradual change of composition in Fe-Pt alloy nanowires along the length under certain AC parameters. The observed dependency of alloy composition on the deposition voltage and frequency of AC electrodeposition is explained by an interplay between reduction potentials and diffusion coefficients of Fe and Pt ions which makes FePt system able to access compositionally graded nanowires. Magnetic measurements of nanowires of as-deposited nanowires confirm that maximum coercivity of 1.55 kOe is observed for nearly stoichiometric composition which increases up to 1.81 kOe after thermal annealing at 550 °C. - Graphical abstract: Evaluation of synthesizing extrinsic parameters (such as deposition voltages and frequency) and intrinsic parameters (diffusion coefficient and reduction potential of ion species) in compositionally graded Fe{sub (1−x)}-Pt{sub (x)} nanowires prepared by alternating current electrodeposition into alumina templates.

36 MATERIALS SCIENCE↗

Bistable Black Electrochromic Windows Based on the Reversible Metal Electrodeposition of Bi and Cu

Optically tunable windows based on reversible metal electrodeposition are an exciting alternative to static lighting control methods such as blinds and shades. In this Letter, we study reversible Bi/Cu electrodeposition on Pt-modified transparent conducting electrodes for electrochromic applications. Spectroelectrochemical measurements combined with scanning electron microscopy images indicate that the electrolytic Bi:Cu ratio drastically affects the electrode switching speed and electrodeposit morphology, which we propose is due to the galvanic displacement of Bi by Cu + . These findings allow us to construct 25 cm 2 black dynamic windows with reversibly tunable transmission at fast switching speeds. This rapid cycling can be maintained over 1000 cycles without degradation in contrast or uniformity. Lastly, the Bi–Cu windows consume no power to maintain either their transparency or opacity, making them promising candidates for energy-efficient devices. Their combination of fast switching, color neutrality, durable cycling, and dual-state resting stability make dynamic windows based on Bi–Cu reversible electrodeposition promising and competitive alternatives to traditional electrochromic materials.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Water Interplays during Dysprosium Electrodeposition in Pyrrolidinium Ionic Liquid: Deconvoluting the Pros and Cons for Rare Earth Metallization

The electrochemical production of rare earth metals (REMs) in ionic liquids (ILs) has received much attention as a promising, sustainable and replacement to the molten salt electrolysis. Water additives have been recently suggested as a strategy to overcome the limitations of the ionic liquid process, but without complete assessment of its overall viability for the REMs production. In this regard, a full investigation of water impact on dysprosium (Dy) electrodeposition in pyrrolidinium triflate (BMPyOTf) ionic liquid was carried out. Water introduction was revealed to involve an interplay of implications on the electrodeposition process, including coordination, speciation, reduction pathways, interfacial dynamics, nucleation and metal stability and purity. In highly dry conditions, the reduction occurs at very negative potentials (-3.3V) in a consecutive pathway, resulting in negligible metal electrodeposition (low rate and efficiency) at the electrode surface. Initial water introduction (<30% molar fraction) leads to partitioning of the Dy complex between water and IL coordinated speciation, giving rise to an additional wave at more positive potentials (-2.4V). Probing and quantification of the heterogeneous Dy speciation by spectroscopic analyses enabled the uncovering of the reduction mechanism and accurate evaluation of the mass transport properties. While lowering the reduction thermodynamics, water addition also improved the nucleation, deposition rate and faradaic efficiency. In spite of these benefits, stripping voltammetric analysis also indicated substantial chemical reactivity of the deposited Dy metal with water additives and/or electrolyte components, under extended timescales. Surface characterization of the obtained product confirmed limited Dy metal stability (mostly oxidized/fluorinated) and purity (~60%) in the studied system. Moreover, high water introduction (>30% molar fraction) was shown to trigger a fast hydrogen evolution reaction (HER), downgrading the robustness of system efficiency. We report the overall impact of water additives seems to engender both promoting and mitigating effects on the Dy electrodeposition process, making the case for more innovative strategies to be sought.

36 MATERIALS SCIENCE↗

Electrochemical cell for in situ electrodeposition of magnetic thin films in a superconducting quantum interference device magnetometer

An electrochemical cell is designed and applied for in situ electrodeposition of magnetic thin films in a commercial SQUID magnetometer system. The cell is constructed in such a way that any parasitic contribution of the cell and of the substrate for electrodeposition to the magnetic moment of the deposited film is reduced to a minimum. A remanent minor contribution is readily taken into account by a proper analysis of the detected signal. Thus, a precise determination of the absolute magnetic moment of the electrodeposited magnetic film during its growth and dissolution is achieved. The feasibility of the cell design is demonstrated by performing Co electrodeposition using cyclic voltammetry. For an average Co film thickness of (35.6 ± 3.0) atomic layers, a magnetic moment per Co atom of (1.75 ± 0.11) μ{sub B} was estimated, in good agreement with the literature bulk value.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Non-enzymatic glucose sensor based on electrodeposited copper on carbon paste electrode (Cu/CPE)

The development of non-enzymatic glucose sensor has much attention due to their applications in glucose monitoring. In this research, copper oxide is used as a non-enzymatic glucose sensor by oxidizing glucose to gluconolactone. Copper was electrodeposited on Carbon paste electrode (CPE) at constant potential. The experimental condition was varied in electrodeposition of Cu with the following parameters: Electrodeposition time 60 s, 120 s and 180 s and potential reduction -0.166 V, -0.266 V and -0.366 V. The effective performance of these working electrodes in sensing glucose was investigated. The Cu/CPE which used -0.366 V potential reduction and 120 s electrodeposition time shows the best performance. The amperometric response current in concentration range 1.6-62.5 mM of glucose gives the good linearity R{sup 2} = 0.9988, low detection limit 0.6728 mM and high sensitivity 1183.59 µA mM{sup −1}cm{sup −2}. Furthermore this sensor exhibited a good repeatability with %RSD = 1.31% (n=10) and high stability with %RSD = 1.51% (n=5 days). The homogeneity of Cu particles on CPE was investigated by Scanning Electron Microscope (SEM).

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

Thin-Layer Electrodeposition of Uranium Metal from Molten LiCl-KCl

A uranium metal electrodeposition extension to the previously proposed analytical technique for determining actinides in molten salts is presented. The technique combines information from electrodeposition with the output of an alpha particle detector. This technique requires a thin actinide layer to be deposited on a metal substrate. Electrodeposition of a thorium layer has been reported previously. Electrodeposition of a thin uranium layer from molten LiCl-KCl onto nickel plates is reported in this paper using repeating chronoamperometry. Alloy formation was encountered which caused unusual deposit morphology. Furthermore, the effect of uranium concentration on time to deposit a fixed amount was determined. Re-usability of the detectors was shown via demonstrating the anodic stripping of the deposit verified by surface analysis (SEM-EDS).

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Nanostructured Electrolytes for Stable Lithium Electrodeposition in Secondary Batteries

Secondary batteries based on lithium are the most significant energy storage technology for contemporary portable devices. The lithium ion battery (LIB) in widespread commercial use today is a compromise technology. It compromises high energy, high power, and design flexibility for long cell operating lifetimes and safety. Materials science, transport phenomena, and electrochemistry in the electrodes and electrolyte that constitute such batteries are areas of active study worldwide because significant improvements in storage capacity and cell lifetime are required to meet new demands, including the electrification of transportation and for powering emerging autonomous aircraft and robotics technologies. By replacing the carbonaceous host material used as the anode in an LIB with metallic lithium, rechargeable lithium metal batteries (LMBs) with higher storage capacity and compatibility with low-cost, high-energy, unlithiated cathodes such as sulfur, manganese dioxide, carbon dioxide, and oxygen become possible. Large-scale, commercial deployment of LMBs are today limited by safety concerns associated with unstable electrodeposition and lithium dendrite formation during cell recharge. LMBs are also limited by low cell operating lifetimes due to parasitic chemical reactions between the electrode and electrolyte. These concerns are greater in rechargeable batteries that utilize other, more earth abundant metals such as sodium and to some extent even aluminum. Inspired by early theoretical works, various strategies have been proposed for alleviating dendrite proliferation in LMBs. A commonly held view among these early studies is that a high modulus, solid-state electrolyte that facilitates fast ion transport, is nonflammable, and presents a strong-enough physical barrier to dendrite growth is a requirement for any commercial LMB. Unfortunately, poor room-temperature ionic conductivity, challenging processing, and the high cost of ceramic electrolytes that meet the modulus and stability requirements have to date proven to be insurmountable obstacles to progress. In this Account, we first review recent advances in continuum theory for dendrite growth and proliferation during metal electrodeposition. We show that the range of options for designing electrolytes and separators that stabilize electrodeposition is now substantially broader than one might imagine from previous literature accounts. In particular, separators designed at the nanoscale to constrain ion transport on length scales below a theory-defined cutoff, and structured electrolytes in which a fraction of anions are permanently immobilized to nanoparticles, to a polymer network or ceramic membrane are considered particularly promising for their ability to stabilize electrodeposition of lithium metal without compromising ionic conductivity or room temperature battery operation. Furthermore, we review recent progress in designing surface passivation films for metallic lithium that facilitate fast deposition of lithium at the electrolyte/electrode interface and at the same time protect the lithium from parasitic side reactions with liquid electrolytes. An enticing finding from both theory and experiment is that simple film-forming halide salt additives in a conventional liquid electrolyte can substantially extend the lifetime and safety of LMBs.

25 ENERGY STORAGE↗

Electrodeposition of Zinc in Aqueous Electrolytes Containing High Molecular Weight Polymers

Strong polarization of the ion distribution in liquid electrolytes subjected to potential differences exceeding the thermal voltage, V T = kT/e, produces a hydrodynamic instability termed electroconvection at ion-selective interfaces. Electroconvection is desirable in some situations (e.g., electrodialysis) because it promotes mixing in a stagnant electrolyte layer, enhancing the ion flux at a fixed potential difference. It is undesirable in others (e.g., electrodeposition of metals) where early experiments show that convective fluid rolls associated with hydrodynamic instability in bounded electrolytes produce preferential metal deposition at localized regions on an electrode. Such localized deposition drives the family of morphological instabilities loosely termed dendritic electrodeposition. We experimentally investigate the effect of ultrahigh molecular weight polymer additives on the onset conditions and physical characteristics of both instabilities. Direct observations of electrodeposit morphology and tracer particle motions used in tandem with indirect electrokinetic measurements reveal that even at moderate concentrations, the polymer additives have a large beneficial effect in extending the range of electric potentials where stable electrodeposition is observed. Additionally, we report that at polymer concentrations above the entanglement threshold, high molecular weight polymers impart elasticity to liquid electrolytes which dampen electroconvective flow at a cation-selective interface but have at most a minimal effect on the bulk ionic conductivity of the liquid.

25 ENERGY STORAGE↗

Separator Effect on Zinc Electrodeposition Behavior and Its Implication for Zinc Battery Lifetime

We report uncontrolled zinc electrodeposition is an obstacle to long-cycling zinc batteries. Much has been researched on regulating zinc electrodeposition, but rarely are the studies performed in the presence of a separator, as in practical cells. Here, we show that the microstructure of separators determines the electrodeposition behavior of zinc. Porous separators direct zinc to deposit into their pores and leave “dead zinc” upon stripping. In contrast, a nonporous separator prevents zinc penetration. Such a difference between the two types of separators is distinguished only if caution is taken to preserve the attachment of the separator to the zinc-deposited substrate during the entire electrodeposition–morphological observation process. Failure to adopt such a practice could lead to misinformed conclusions. Our work reveals the mere use of porous separators as a universal yet overlooked challenge for metal anode-based rechargeable batteries. Countermeasures to prevent direct exposure of the metal growth front to a porous structure are suggested.

25 ENERGY STORAGE↗

Electrodeposited Zinc-based Films as Anodes for Aqueous Zinc Batteries

Zinc-based batteries have attracted extensive attention in recent years, due to high safety, high capacities, environmental friendliness, and low cost compared to lithium ion batteries. However, the zinc anode suffers primarily from dendrite formation as a mode of failure in the mildly acidic system. Herein, we report on electrochemically deposited zinc (ED Zn) and copper-zinc (brass) alloy anodes, which are critically compared with a standard commercial zinc foil. The film electrodes are of commercially relevant thicknesses (21 and 25µM). The electrodeposited zinc-based anodes exhibit low electrode polarization (~0.025V) and stable cycling performance in 50 cycle consecutive experiments from 0.26-10 mA cm-2 compared to commercial Zn foil. Coulombic efficiencies at 1 mA cm-2 were over 98% for the electrodeposited zinc-based materials and were maintained for over 100 cycles. Furthermore, full cells with an electrodeposited Zn/brass anode, EMD MnO2 cathode, in 1M ZnSO4 + 0.1M MnSO4 delivered capacities of 96.3, and 163 mAh g-1, respectively, at a 100 mA g-1 compared to 92.1 mAh g-1 for commercial Zn. The zinc-based anodes also show better rate capability, delivering full cell capacities of 35.9 and 47.5 mAh g-1 at high current of up to 3 A g-1. Lastly, the electrodeposited zinc-based anodes show enhanced capacity for up to 100 cycles at 100 mA g-1, making them viable anodes for commercial use.

Fayette, Matthew R.↗

Stabilizing Dendritic Electrodeposition by Limiting Spatial Dimensions in Nanostructured Electrolytes.

The tendency of metals to form uncontrolled dendritic morphologies during electrodeposition hinders the development of safe and reliable metal batteries. Multiphase nanostructured electrolytes can suppress dendritic growth if the mechanical modulus of the electrolyte is high relative to that of the metal or if the conducting channels are confined to nanoscale dimensions. Direct visualization and analysis of electrodeposition within polymeric nanostructures elucidates the structure-property relationships and mechanisms underlying the suppression of dendrite growth. Here, we fabricate precisely structured multiphase films composed of nanochannels of a polymeric electrolyte in a background of nonconductive polymer on top of coplanar electrodes. The devices enable imaging and analysis of electrodeposition behavior as a function of channel width by scanning electron microscopy. We find that electrodeposition is confined to individual conductive channels and that radial propagation of the dendritic morphology is suppressed in channels for which the width is smaller than the characteristic dendritic nucleation size.

Sharon, Daniel↗

Stable lithium electrodeposition in liquid and nanoporous solid electrolytes

Rechargeable lithium, sodium and aluminium metal-based batteries are among the most versatile platforms for high-energy, cost effective electrochemical energy storage. Non-uniform metal deposition and dendrite formation on the negative electrode during repeated cycles of charge and discharge are major hurdles to commercialization of energy-storage devices based on each of these chemistries. A long-held view is that unstable electrodeposition is a consequence of inherent characteristics of these metals and their inability to form uniform electrodeposits on surfaces with inevitable defects. Here, we report on electrodeposition of lithium in simple liquid electrolytes reinforced with halogenated salt blends exhibit stable long-term cycling at room temperature, often with no signs of deposition instabilities over hundreds of cycles of charge and discharge and thousands of operating hours. We rationalize these observations with the help of surface energy data for the electrolye/lithium interface and impedance analysis of the interface during different stages of cell operation. Our finding provide support for an important and recent theoretical prediction that the surface mobility of lithium is significantly enhanced in the presence of lithium halide salts. Finally, our results also show that a high electrolyte modulus is unnecessary for stable electrodeposition of lithium.

36 MATERIALS SCIENCE↗

Electrodeposition of ligand-free copper nanoparticles from aqueous nanodroplets

Copper nanoparticles have emerged as promising electrocatalysts for energy storage and conversion. Generally, homogenous nanoparticle synthesis requires a stabilizing ligand, which may influence the electrocatalysis. Ligands can be avoided by direct nanoparticle electrodeposition. Here, we extend nanodroplet-mediated electrodeposition to the electrodeposition of copper nanoparticles from aqueous nanodroplets suspended in 0.1 M tetrabutylammonium hexafluorophosphate ([TBA][PF 6 ]) and 1,2-dichloroethane. Stochastic electrochemistry on microelectrodes was used to elucidate nanoparticle growth kinetics for various solution conditions and substrate materials. A study on the effect of surfactants on nanoparticle morphology and growth kinetics demonstrated the surfactant's role as an avenue for morphological control. Nanoparticle morphology was studied by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). Energy-dispersive X-ray Spectroscopy (EDX) confirmed the presence of copper nanoparticles. TEM and Selected Area Electron Diffraction (SAED) confirmed nanoparticle size, morphology, and polycrystallinity. We demonstrate tunable nanoparticle size using cyclic voltammetry on single aqueous nanodroplets by altering the voltammetric sweeping potentials of copper electroreduction. Finite element simulations validate the voltammetric response and ability to control the nanoparticle size with nanometer resolution during a voltammetric sweep. These results inform the electrodeposition of copper nanoparticles from aqueous nanodroplets for important applications, such as the conversion of CO 2 to hydrocarbon fuels.

36 MATERIALS SCIENCE↗

LiCl–Based Aqueous Electrolytes for Efficient Iron Electrodeposition

This study investigates room temperature, aqueous electrolytes for efficient iron electrodeposition. Specifically, a novel lithium chloride-based electrolyte was identified to suppress hydrogen evolution while promoting fast kinetics of iron electrodeposition, achieving high coulombic efficiency (>90%) at high current densities (>400 mA cm −2 ). Electrochemical analysis of the partial current densities of iron deposition and hydrogen co-evolution revealed that water reduction is kinetically suppressed in this electrolyte, resulting in an increase in the measured coulombic efficiency. Furthermore, a detailed investigation of the iron speciation and their complexation was performed, which revealed that, in concentrated LiCl-containing electrolytes, the ferrous (Fe 2+ ) species coordinate with chloride rather than water, enhancing deposition kinetics. The combined effect of enhanced electrodeposition kinetics and suppressed water activity provide elevated coulombic efficiency. Overall, this paper develops an understanding of anion and cation effects on the mechanism of electrodeposition and hydrogen co-evolution in concentrated electrolytes in search of improved aqueous media (e.g., concentrated LiCl) for efficient metal electro-synthesis.

Lvovich, William [Case Western Reserve University,↗

Electrodeposition of Tungsten using Hydrotropic Agents

The current work sought to electrodeposit tungsten from water-based solutions. The work’s initial hypothesis was that methoxide reducing agents could be used to generate urea anions that could enable tungsten electrodeposition. Unfortunately, this hypothesis was found to be incorrect. However, the work led to the understanding that chemical reducing agents not only enable the electrodeposition of refractory metals like rhenium from water-based solutions, but that the key to plating tungsten in the future involves chemical reduction followed by stabilization with proper ligands. The work resulted in a manuscript under review at Inorganic Chemistry Communications on the discovered of L-histidine as a suitable reducing agent from rhenium electrodeposition. Rhenium-tungsten alloys with 4% tungsten were deposited. A technical advance was filed for the rhenium chemistry and parts were delivered to an internal Sandia customer that used the chemistry.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗