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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.

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At least 1,117 records · Page 62
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Perspective—Lithium Metal Nucleation and Growth on Conductive Substrates: A Multi-Scale Understanding from Atomistic, Nano-, Meso-, to Micro-Scales

Reversible lithium (Li) deposition and stripping on conductive substrates like copper is vital for long-life high-energy rechargeable Li batteries. The reversibility is believed hindered by solid electrolyte interphase (SEI) formation and Li dendritic growth. Via in situ, operando cryo-microscopy and molecular dynamics simulation, we discovered amorphous Li before a disorder-order phase transition to bcc phase. The kinetics plays a significant role in Li nucleation and morphology evolution. This perspective on Li nucleation and growth from atomistic to nano- (<20 nm), meso- (20–100 nm), and micro-scales (>100 nm) provides a practical guidance on regulating dense Li deposits reversibly for long life performance.

25 ENERGY STORAGE↗
DOE OSTI2025

A Diffuse-Interface Model for Predicting the Evolution of Metallic Negative Electrodes and Interfacial Voids in Solid-State Batteries with Homogeneous and Polycrystalline Solid Electrolyte Separators

Here, this paper presents a novel diffuse-interface electrochemical model that simultaneously simulates the evolution of the metallic negative electrode and interfacial voids during the stripping and plating processes in solid-state batteries. The utility and validity of this model are demonstrated for the first time on a cell with a sodium (Na) negative electrode and a Na-β″-alumina ceramic solid electrolyte (SE) separator. Three examples are simulated. First, stripping and plating with a perfect electrode/electrolyte interface; second, stripping and plating with a single interfacial void at the electrode/electrolyte interface; third, stripping with multiple interfacial voids. Both homogeneous and polycrystalline SEs with low and high-conductivity grain boundaries (GBs) are considered for all three examples. Heterogeneous GB conductivity marginally impacts the thickness of the Na electrode in cases with a perfect electrode/electrolyte interface. Moreover, it results in local changes to void growth due to the interactions between the void edge and the GBs. The void growth rate is a linear function of the flux of Na atoms at the void edge, which in turn depends on the applied current density. We also show that the void coalescence rate increases with applied current density and can be marginally influenced by GB conductivity.

batteries↗
DOE OSTI2017

Deposition of tungsten metal by an immersion process

A new multi-step, solution-phase method for the spontaneous deposition of tungsten from a room temperature ethereal solution is reported. This immersion process relies on the deposition of a sacrificial zinc coating which is galvanically displaced by the ether-mediated reduction of oxophilic WCl 6 . Subsequent thermal treatment renders a crystalline, metallic tungsten film. The chemical evolution of the surface and formation of a complex intermediate tungsten species is characterized by X-ray diffraction, infrared spectroscopy, and X-ray photoelectron spectroscopy. Efficient metallic tungsten deposition is first characterized on a graphite substrate and then demonstrated on a functional carbon foam electrode. The resulting electrochemical performance of the modified electrode is interrogated with the canonical aqueous ferricyanide system. A tungsten-coated carbon foam electrode showed that both electrode resistance and overall electrochemical cell resistance were reduced by 50%, resulting in a concomitant decrease in redox peak separation from 1.902 V to 0.783 V. Furthermore, this process promises voltage efficiency gains in electrodes for energy storage technologies and demonstrates the viability of a new route to tungsten coating for technologies and industries where high conductivity and chemical stability are paramount.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Galvanostatic Plating with a Single Additive Electrolyte for Bottom-Up Filling of Copper in Mesoscale TSVs

A methanesulfonic acid (MSA) electrolyte with a single suppressor additive was used for potentiostatic bottom-up filling of copper in mesoscale through silicon vias (TSVs). Conversly, galvanostatic deposition is desirable for production level full wafer plating tools as they are typically not equipped with reference electrodes which are required for potentiostatic plating. Potentiostatic deposition was used to determine the over-potential required for bottom-up TSV filling and the resultant current was measured to establish a range of current densities to investigate for galvanostatic deposition. Galvanostatic plating conditions were then optimized to achieve void-free bottom-up filling in mesoscale TSVs for a range of sample sizes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Electrochemical Nucleation and Growth of Uranium and Plutonium from Molten Salts

This work examines the nucleation and growth behavior of uranium and plutonium from molten LiCl-KCl eutectic on inert electrodes using electrochemical techniques. Current-time transients obtained from chronoamperometric experiments were compared with theoretical models to characterize the type of nucleation (progressive or instantaneous) for deposition of U and Pu, and co-deposition of U-Pu, from molten LiCl-KCl at inert electrodes. It was established that the nucleation mode of actinides present as chlorides in molten chloride salts changes from progressive to instantaneous with an increasing concentration of the trivalent actinide ions in the salt. The effect of the material of the working electrode was investigated, and it was found that changing the material from tungsten to silver improves resolvability of the nucleation peaks and allows more accurate analysis of the experimental measurements. Using the nucleation data, diffusion coefficients were obtained for U 3+ and Pu 3+ , and were found to be in very good agreement with the values obtained from other studies. Furthermore, the density of nuclei produced during instantaneous nucleation, the rate of nucleation for progressive nucleation, and the radius of the deposited nuclei were evaluated and examined at different overpotentials.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2019

Understanding the Role of Complexation in the Charge-Transfer Kinetics of the Cu 2+ + e ↔ Cu 1+ Redox Reaction in Ethaline Deep Eutectic Solvent

Deep eutectic solvent (DES) based electrolytes are gaining attention for electrochemical applications. As such, knowledge of the charge transfer kinetics in DES and its dependence on electrolyte composition and temperature is important. Using Cu 2+ + e ↔ Cu 1+ as a model system, we demonstrate that metal redox reactions in chloride-containing DES media suffer from sluggish charge transfer kinetics. The exchange current density, i 0 , displayed a peculiar inverse relationship with the bulk chloride concentration, [Cl – ] b . The i 0 decreased from 7.9 to 3.0 mA/cm 2 when [Cl – ] b increased from 2.8 to 4.6 M at 30°C. Such dependence is shown to originate from Cl – complexation with reactant and product species. Furthermore, i 0 increased with an increase in Cu n + bulk concentration in the 50–200 mM range. Also, increase in temperature elevated i 0 . The charge transfer coefficient α c , however, remained constant (~0.5) and was unaffected by Cu n + or Cl – concentrations or by temperature. To explain how charge transfer kinetics depend on the various system parameters, a model incorporating complexation phenomena was developed and its predictions were compared to experiments.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2014

Stabilizing the surface of lithium metal

Lithium metal is an ideal anode for the next generation of high capacity rechargeable batteries, including Li-air, Li-S, and other Li-based batteries using intercalation compounds. To enable the broad applications for lithium anodes, more fundamental studies need to be conducted to simultaneously address the two barriers discussed above. One of the key breakthroughs in this field may come from the development of new electrolytes (and additives) which can form a stable SEI layer with enough mechanical strength and flexibility. The ideal electrolyte may consist of only two components; one component inhibits dendrite growth, while another component forms a stable SEI layer to improve Coulombic efficiency. In this review, the status of three approaches at manipulating and controlling the lithium metal – electrolyte interface were discussed. While previous studies concentrated on coatings with minimal surface connectivity, the approaches discussed, namely a coating that forms and dissipates into the electrolyte based on charge density, a coating bonded to the termination layer of lithium, and a conformal carbonate coating formed at the interface, all highlight new research directions. Although there are still many obstacles to be overcome, we are optimistic that Li metal can be used as an anode in rechargeable batteries in the foreseeable future. This will enable wide

36 MATERIALS SCIENCE↗
DOE OSTI2018

Approaches toward lithium metal stabilization

Historically, batteries with lithium metal anodes have been a hazard, as the lithium becomes rough and eventually finely divided during cycling. The promise of higher energy density, however, continues to drive the search for novel approaches to manage this light and reactive material. Significant improvement has been achieved by designing new liquid-electrolyte compositions and interface barriers to stabilize the lithium in traditional batteries, but it is clear that solid-state batteries ensure a higher level of safety and perhaps higher energy density and lifetimes. The materials challenge then is to fabricate a cost-effective solid electrolyte that effectively maintains lithium as a dense uniform metal layer. This review paper describes the ideal cycling behavior of lithium and progress toward this goal of a solid electrolyte using glassy, ceramic, polymer, and composite electrolytes, as well as the challenges that continue to arise toward long-term, high-rate, and efficient cycling of lithium metal.

25 ENERGY STORAGE↗
DOE OSTI2014

Stable-isotope probe of nano-scale mineral-fluid redox interactions

The project examined how stable isotopes fractionate at an aqueous/solid interface during electrochemical reduction reactions. Measurements in a wide variety of metal deposition systems including Fe, Zn, Li, Mo, and Cu, have led to observations of large isotope fractionations which strongly vary as a function of rate and temperature. For the Fe, Zn, and Li systems, our electrochemical deposition methods provide the largest single-pass fractionation factors that are observed for these systems. Based on these and other experiments and theory showing and predicting significant and rate-dependent fractionations of isotopes at reacting interfaces, we have developed a simple statistical mechanics framework that predicts the kinetic isotope effect accompanying phase transformations in condensed systems. In addition, we have begun to extend our studies of mineral-fluid redox interactions to high pressures and temperatures in the diamond anvil cell. We performed a series of experiments to determine solubilities of Cu and Ni at elevated pressure and temperature conditions relevant to ore-formation.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Diffusional Boriding of Subeutectoidal Tool Steels: Technology and Outcome

Structural, subeutectoidal structural, and tool steels are studied. Their boriding is considered. Equipment for electrolytic boriding and a modernized high-temperature casting crucible are presented. The conditions of electrolytic boriding are established. Shortcomings of electrolytic boriding are noted.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Magnetically Ordered Electrolytic Coatings in Hydraulic Systems

The application of wear-resistant coatings in the presence of a magnetic field is proposed for components of hydraulic systems. A method is developed for controlling the residual stress and mechanical properties by means of crystallographic anisotropy.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Solvation, Rational Design, and Interfaces: Development of Divalent Electrolytes

Rechargeable multivalent ion batteries are promising tools to complement current lithium-ion batteries for a future of diverse energy storage needs. Divalent Mg and Ca are attractive candidates for their high crustal abundance, high volumetric anode capacity, and infrequent dendrite formation during electrochemical cycling. Electrolyte research is central to these efforts and continually improves coulombic efficiencies towards the ideal 100%. This mini-review discusses recent work towards fundamental understandings that push these chemistries towards practical use. Piecing together compatible cathode and electrolytes for a complete practical multivalent ion battery lacks a cohesive method for further development and refinement. Understanding liquid solvation, utilizing rational design, and probing interfacial interactions are focal points that govern electrolyte performance. The combination of these areas will be critical for meaningful development.

25 ENERGY STORAGE↗
DOE OSTI2019

Copper-Tin Alloys for the Electrocatalytic Reduction of CO2 in an Imidazolium-Based Non-Aqueous Electrolyte

The ability to synthesize value-added chemicals directly from CO2 will be an important technological advancement for future generations. Using solar energy to drive thermodynamically uphill electrochemical reactions allows for near carbon-neutral processes that can convert CO2 into energy-rich carbon-based fuels. Here, we report on the use of inexpensive CuSn alloys to convert CO2 into CO in an acetonitrile/imidazolium-based electrolyte. Synergistic interactions between the CuSn catalyst and the imidazolium cation enables the electrocatalytic conversion of CO2 into CO at −1.65 V versus the standard calomel electrode (SCE). This catalyst system is characterized by overpotentials for CO2 reduction that are similar to more expensive Au- and Ag-based catalysts, and also shows that the efficacy of the CO2 reduction reaction can be tuned by varying the CuSn ratio.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2015

The MAJORANA Project: a status report

This series of slides presents the topic under the following aspects: ββ sensitivity, underground laboratory, shield, monoliths, strings, detectors, electroformed small parts, and background. Assembly and construction are proceeding at Sanford Davis Campus laboratory. Based on assays, material backgrounds are projected to meet cleanliness goals. Module 1 is complete. Electroformed copper has just been completed at SURF and PNNL. The shield is nearly complete. Successful reduction and refinement of enr Ge has taken place with 98% yield. AMTEK (ORTEC) has produced 27 kg within 32 detectors from the reduced/refined enr Ge; 30 of these are underground at SURF being assembled into strings.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗