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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 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
NASA NTRS1992

Capacity retention in hydrogen storage alloys

Results of our examination of the properties of several candidate materials for hydrogen storage electrodes and their relation to the decrease in H-storage capacity upon open-circuit storage over time are reported. In some of the alloy samples examined to date, only about 10 percent of the hydrogen capacity was lost upon storage for 20 days, while in others, this number was as high as 30 percent for the same period of time. This loss in capacity is attributed to two separate mechanisms: (1) hydrogen desorbed from the electrode due to pressure differences between the cell and the electrode sample; and (2) chemical and/or electrochemical degradation of the alloy electrode upon exposure to the cell environment. The former process is a direct consequence of the equilibrium dissociation pressure of the hydride alloy phase and the partial pressure of hydrogen in the hydride phase in equilibrium with that in the electrolyte environment, while the latter is related to the stability of the alloy phase in the cell environment. Comparison of the equilibrium gas-phase dissociation pressures of these alloys indicate that reversible loss of hydrogen capacity is higher in alloys with P(eqm) greater than 1 atm than in those with P(eqm) less than 1 atm.

Anani, A.↗
DOE OSTI2022

Gradient Architecture Design in Scalable Porous Battery Electrodes

Because it has been demonstrated to be effective toward faster ion diffusion inside the pore space, low-tortuosity porous architecture has become the focus in thick electrode designs, and other possibilities are rarely investigated. Here, to advance current understanding in the structure-affected electrochemistry and to broaden horizons for thick electrode designs, we present a gradient electrode design, where porous channels are vertically aligned with smaller openings on one end and larger openings on the other. With its 3D morphology carefully visualized by Raman mapping, the electrochemical properties between opposite orientations of the gradient electrodes are compared, and faster energy storage kinetics is found in larger openings and more concentrated active material near the separator. As further verified by simulation, this study on gradient electrode design deepens the knowledge of structure-related electrochemistry and brings perspectives in high-energy battery electrode designs.

25 ENERGY STORAGE↗
DOE OSTI2025

Cycling Performance and Structure Evolution of Co-Free Lithium- and Manganese-Rich Layered Oxides in Lithium-Ion Batteries

Lithium- and manganese-rich (LMR) layered oxides are high-capacity cathode materials that are being considered for electric vehicle (EV) lithium-ion batteries (LIBs). Here, we investigate the electrochemical cycling behavior of cells containing a cobalt-free LMR oxide, 0.3Li 2 MnO 3 ·0.7LiMn 0.5 Ni 0.5 O 2 , paired with either Li or graphite anodes. Two- and three-electrode cells are cycled under varying conditions to examine the effects of oxide activation, upper cutoff voltage, separator type, and electrolyte composition. Post-cycling characterization of harvested electrodes, with electrochemical, X-ray absorption spectroscopy, and solid-state 6 Li nuclear magnetic resonance spectroscopy techniques, are used to correlate cell performance changes with redox state evolution in the oxide and Li inventory shifts in the cell. Our results show that capacity fade and impedance rise primarily originate at the graphite anode and LMR cathode, respectively. Notably, while Ni undergoes reversible redox, Mn shows no evidence of bulk redox activity even in highly-aged electrodes: only relithiated LMR electrodes show some reduction of Mn. Graphite electrodes degrade due to particle isolation and SEI growth, exacerbated by Mn dissolution and deposition on graphite anodes. These findings highlight the coupled structural and electrochemical degradation mechanisms in LMR/graphite cells and underscore lithium inventory retention and electrode interfacial stability as critical factors for enhancing long-term performance.

Badami, Pavan P. [Argonne National Laboratory (ANL↗
NASA NTRS1989

Impedance studies of Ni/Cd and Ni/H2 cells using the cell case as a reference electrode

Impedance measurements have been made on several Ni/Cd and Ni/H2 flightweight cells using the case as a reference electrode. For these measurements the voltage of the case with respect to the anode or cathode is unimportant provided that it remains stable during the measurement of the impedance. In the cells measured so far, the voltages of the cell cases with respect to the individual electrodes differ from cell to cell even at the same overall cell voltage, but they remains stable with time. The measurements can thus be used to separate the cell impedance into the contributions of each electrode, allowing improved diagnosis of cell problems.

Reid, Margaret A.↗
NASA NTRS1990

Impedance studies of nickel/cadmium and nickel/hydrogen cells using the cell case as a reference electrode

Impedance measurements have been made on several Ni/Cd and Ni/H2 flight-weight cells using the case as a reference electrode. For these measurements, the voltage of the case with respect to the anode or cathode is unimportant provided that it remains stable during the measurement of the impedance. In the cells measured so far, the voltage of the cell cases with respect to the individual electrodes differ from cell to cell, even at the same overall cell voltage, but they remain stable with time. The measurements can thus be used to separate the cell impedance into the contributions of each electrode, allowing improved diagnosis of cell problems.

Reid, Margaret A.↗
DOE OSTI2020

Patterned electrode catalyst

Disclosed herein are embodiments of a patterned electrode comprising regions of catalyst and segregating regions that separate the regions of catalyst. The segregating regions may be regions of non-catalytic material. The catalyst regions may correspond to the channels of a flow field. The electrode provides improved fuel cell performance, particularly at high current densities. The electrode may be for all suitable applications, such as in a membrane electrode assembly and/or a fuel cell. Also disclosed is a method for making the patterned electrode. The method may comprise using masks to apply the catalyst and non-catalyst material to a substrate.

Macauley, Natalia↗
DOE OSTI2020

Spatial dynamics of lithiation and lithium plating during high-rate operation of graphite electrodes

The principal inhibitor of fast charging lithium ion cells is the graphite negative electrode, where favorable conditions for lithium plating occur at high charge rates, causing accelerated degradation and safety concerns. The local response of graphite, both at the electrode and particle level, when exposed to fast charging conditions of around 6C is not well understood. Consequently, the conditions that lead to the onset of lithium plating, as well as the local dynamics of lithium plating and stripping, have also remained elusive. Here, we use high-speed (100 Hz) pencil-beam X-ray diffraction to repeatedly raster along the depth of a 101 μm thick graphite electrode in 3 μm steps during fast (up to 6C) charge and discharge conditions. Consecutive depth profiles from separator to current collector were each captured in 0.5 seconds, giving an unprecedented spatial and temporal description of the state of the electrode and graphite's staging dynamics during high rate conditions. The electrode is preferentially activated near the separator, and the non-uniformity increases with rate and is influenced by free-energy barriers between graphite's lithiation stages. The onset of lithium plating and stripping was quantified, occurring only within the first 15 μm from the separator. The presence of lithium plating changed the behavior of the underlying graphite, such as causing co-existence of LiC 6 and graphite in the fully discharged state. Finally, the staging behavior of graphite at different rates was quantified, revealing a high dependency on rate and drastic hysteresis between lithiation and delithiation.

25 ENERGY STORAGE↗
DOE OSTI2025

Enhanced Laser-Induced Graphene Microfluidic Integrated Sensors (LIGMIS) for On-Site Biomedical and Environmental Monitoring

The convergence of microfluidic and electrochemical biosensor technologies offers significant potential for rapid, in-field diagnostics in biomedical and environmental applications. Traditional systems face challenges in cost, scalability, and operational complexity, especially in remote settings. Addressing these issues, laser-induced graphene microfluidic integrated sensors (LIGMIS) are presented as an innovative platform that integrates microfluidics and electrochemical sensors both comprised of laser-induced graphene. This study advances the LIGMIS concept by resolving issues of uneven fluid transport, increased hydrophobicity during storage, and sensor biofunctionalization challenges. Key innovations include Y-shaped reservoirs for consistent fluid flow, hydrophilic polyethyleneimine coatings to maintain wettability, and separable microfluidic and electrochemical components enabling isolated electrode nanoparticle metallization and biofunctionalization. Multiplexed electrochemical detection of the neonicotinoid imidacloprid and nitrate ions in environmental water samples yields detection limits of 707 nm and 10 -5.4 m with wide sensing ranges of 5–100 µm and 10 -5 –10 -1 m, respectively. Similarly, uric acid and calcium ions are detected in saliva, demonstrating detection limits of 217 nm and 10 -5.3 m with sensing ranges of 10–50 µm, and 10 -5 –10 -2.5 m, respectively. Overall, this biosensing demonstrates the capability of the LIGMIS platform for multiplexed detection in biologically complex solutions, with applications in environmental water quality monitoring and oral cancer screening.

environmental monitoring↗
DOE OSTI2022

Electrocatalysis in Alkaline Media and Alkaline Membrane-Based Energy Technologies

Hydrogen energy-based electrochemical energy conversion technologies offer the promise of enabling a transition of the global energy landscape from fossil fuels to renewable energy. Here, we present a comprehensive review of the fundamentals of electrocatalysis in alkaline media and applications in alkaline-based energy technologies, particularly alkaline fuel cells and water electrolyzers. Anion exchange (alkaline) membrane fuel cells (AEMFCs) enable the use of nonprecious electrocatalysts for the sluggish oxygen reduction reaction (ORR), relative to proton exchange membrane fuel cells (PEMFCs), which require Pt-based electrocatalysts. However, the hydrogen oxidation reaction (HOR) kinetics is significantly slower in alkaline media than in acidic media. Understanding these phenomena requires applying theoretical and experimental methods to unravel molecular-level thermodynamics and kinetics of hydrogen and oxygen electrocatalysis and, particularly, the proton-coupled electron transfer (PCET) process that takes place in a proton-deficient alkaline media. Extensive electrochemical and spectroscopic studies, on single-crystal Pt and metal oxides, have contributed to the development of activity descriptors, as well as the identification of the nature of active sites, and the rate-determining steps of the HOR and ORR. Among these, the structure and reactivity of interfacial water serve as key potential and pH-dependent kinetic factors that are helping elucidate the origins of the HOR and ORR activity differences in acids and bases. Additionally, deliberately modulating and controlling catalyst-support interactions have provided valuable insights for enhancing catalyst accessibility and durability during operation. The design and synthesis of highly conductive and durable alkaline membranes/ionomers have enabled AEMFCs to reach initial performance metrics equal to or higher than those of PEMFCs. We emphasize the importance of using membrane electrode assemblies (MEAs) to integrate the often separately pursued/optimized electrocatalyst/support and membranes/ionomer components. Operando/in situ methods, at multiscales, and ab initio simulations provide a mechanistic understanding of electron, ion, and mass transport at catalyst/ionomer/membrane interfaces and the necessary guidance to achieve fuel cell operation in air over thousands of hours. We hope that this Review will serve as a roadmap for advancing the scientific understanding of the fundamental factors governing electrochemical energy conversion in alkaline media with the ultimate goal of achieving ultralow Pt or precious-metal-free high-performance and durable alkaline fuel cells and related technologies.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2022

Driving Zn-MnO2 grid-scale batteries: A roadmap to cost-effective energy storage

Highlights Zn-MnO 2 batteries promise safe, reliable energy storage, and this roadmap outlines a combination of manufacturing strategies and technical innovations that could make this goal achievable. Approaches such as improved efficiency of manufacturing and increasing active material utilization will be important to getting costs as low as $100/kWh, but key materials innovations that facilitate the full 2-electron capacity utilization of MnO 2 , the use of high energy density 3D electrodes, and the promise of a separator-free battery with greater than 2V potential offer a route to batteries at $50/kWh or less. Abstract Large-scale energy storage is certain to play a significant, enabling role in the evolution of the emerging electrical grid. Battery-based storage, while not a dominant form of storage today, has opportunity to expand its utility through safe, reliable, and cost-effective technologies. Here, secondary Zn–MnO 2 batteries are highlighted as a promising extension of ubiquitous primary alkaline batteries, offering a safe, environmentally friendly chemistry in a scalable and practical energy dense technology. Importantly, there is a very realistic pathway to also making such batteries cost-effective at price points of $50/kWh or lower. By examining manufacturing examples at the Zn–MnO 2 battery manufacturer Urban Electric Power, a roadmap has been created to realize such low-cost systems. By focusing on manufacturing optimization through reduced materials waste, scalable manufacturing, and effective materials selection, costs can be significantly reduced. Ultimately, though, coupling these approaches with emerging research and development advances to enable full capacity active materials utilization and battery voltages greater than 2V are likely needed to drive costs below a target of $50/kWh. Reaching this commercially important goal, especially with a chemistry that is safe, well-known, and reliably effective stands to inject Zn–MnO 2 batteries in the storage landscape at a critical time in energy storage development and deployment. Graphical abstract

Spoerke, Erik D. (ORCID:0000000322862560)↗
NASA NTRS1981

Electrostatic antenna space environment interaction study

The interactions of the electrostatic antenna with the space environment in both low Earth orbit and geosynchronous orbit are investigated. It is concluded that the electrostatically controlled membrane mirror is a viable concept for space applications. However, great care must be taken to enclose the high voltage electrodes in a Faraday cage structure to separate the high voltage region from the ambient plasma. For this reason, metallized cloth is not acceptable as a membrane material. Conventional spacecraft charging at geosynchronous orbit should not be a problem provided ancillary structures (such as booms) are given nonnegligible conductivity and adequate grounding. Power loss due to plasma electrons entering the high field region is a potentially serious problem. In low earth orbit any opening whatever in the Faraday cage is likely to produce an unacceptable power drain.

Katz, I.↗
NASA NTRS1991

A mathematical model of the maximum power density attainable in an alkaline hydrogen/oxygen fuel cell

A mathematical model of a hydrogen/oxygen alkaline fuel cell is presented that can be used to predict the polarization behavior under various power loads. The major limitations to achieving high power densities are indicated and methods to increase the maximum attainable power density are suggested. The alkaline fuel cell model describes the phenomena occurring in the solid, liquid, and gaseous phases of the anode, separator, and cathode regions based on porous electrode theory applied to three phases. Fundamental equations of chemical engineering that describe conservation of mass and charge, species transport, and kinetic phenomena are used to develop the model by treating all phases as a homogeneous continuum.

Kimble, Michael C.↗
DOE OSTI2020

Hybrid anodes for energy storage devices

Energy storage devices having hybrid anodes can address at least the problems of active material consumption and anode passivation that can be characteristic of traditional batteries. The energy storage devices each have a cathode separated from the hybrid anode by a separator. The hybrid anode includes a carbon electrode connected to a metal electrode, thereby resulting in an equipotential between the carbon and metal electrodes.

25 ENERGY STORAGE↗
DOE OSTI2023

Technology Strategy Assessment: Findings from Storage Innovations 2030 Supercapacitors

Electrochemical capacitors, which are commercially called supercapacitors or ultracapacitors, are a family of energy storage devices with remarkably high specific power compared with other electrochemical storage devices. Supercapacitors do not require a solid dielectric layer between the two electrodes, instead they store energy by accumulating electric charge on porous electrodes filled with an electrolyte solution and separated by an insulating porous membrane. Supercapacitors offer large specific capacitance and high power output. They can be charged and discharged very quickly, offer excellent cycle life and long operational life, and operate over a broad temperature range. The major drawbacks of supercapacitors are low energy density and a high self-discharge rate. For example, a supercapacitor passively discharges from 100% to 50% in a month compared with only 5% for a lithium-ion battery [1]. The high capital cost and low energy density of supercapacitors make the unit cost of energy stored ($/kWh) more expensive than alternatives such as batteries. Their attributes make them attractive for uses in which frequent small charges/discharges are required (e.g., ensuring power quality or providing frequency regulation). Their attributes and cost make them less attractive for long-duration energy storage, which favors technologies with low self-discharge that cost less per unit of energy stored.

25 ENERGY STORAGE↗
DOE OSTI2021

Recovery of Cathode Materials and Aluminum Foil Using a Green Solvent

Effective separation of cathode materials and current collectors is one of the most enabling steps, yet a very challenging step, in recycling electrode scraps and spent Li-ion cells. Here, a green solvent, triethyl phosphate, was used to recover invaluable cobalt-containing cathodes, such as NMC622, by dissolving the polymeric binder of poly(vinylidene fluoride). Electrochemically active materials were separated from cathode scraps collected at the manufacturing step of electrodes through a solvent-based separation method without jeopardizing their physical characteristics, crystalline structure, and electrochemical performance. In this work, we found that the recovered aluminum foils were clean without any sign of corrosion and that the polymeric binder could be recovered via a non-solvent-induced phase separation. Additionally, recovery of cathode materials from spent cells was achieved using refined separation parameters based on the recycling of cathode scraps. It is anticipated that this green solvent-based separation for cathode recovery will attract significant interest by the lithium-ion battery manufacturing and recycling communities.

25 ENERGY STORAGE↗
DOE OSTI2023

Redox‐Functionalized Semiconductor Interfaces for Photoelectrochemical Separations

Redox-mediated electrosorption is a promising platform for selective electrochemical (EC) separations, due to its molecular selectivity, high uptake, and tunability for target ions. However, the electrical energy required is mainly generated by non-renewable energy sources, which limits its sustainability and overall impact to decarbonization. Here, a redox-mediated photoelectrochemical (PEC) separation process using polyvinyl ferrocene functionalized TiO 2 nanorod electrodes is proposed, which integrates direct solar energy as a driver for the selective electrosorption. The photoelectrochemically-driven oxidation and reduction with both homogeneous and heterogeneous ferrocene-systems is investigated to establish the underlying mechanism. The PEC system can separate heavy metal oxyanions at lower voltages or even without electrical energy. At 0.3 V versus SCE, a 124 mg g −1 uptake for Mo is achieved, which is comparable to the performance of EC cells at 0.75 V versus SCE. Thus, PEC systems not only can generate energy for spontaneous redox-separations, but also can reduce electrical energy consumption by 51.4% compared to EC cells for separation processes when coupled with an external electrical energy.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS2002

Contactless conductivity detector for microchip capillary electrophoresis

A microfabricated electrophoresis chip with an integrated contactless conductivity detection system is described. The new contactless conductivity microchip detector is based on placing two planar sensing aluminum film electrodes on the outer side of a poly(methyl methacrylate) (PMMA) microchip (without contacting the solution) and measuring the impedance of the solution in the separation channel. The contactless route obviates problems (e.g., fouling, unwanted reactions) associated with the electrode-solution contact, offers isolation of the detection system from high separation fields, does not compromise the separation efficiency, and greatly simplifies the detector fabrication. Relevant experimental variables, such as the frequency and amplitude of the applied ac voltage or the separation voltage, were examined and optimized. The detector performance was illustrated by the separation of potassium, sodium, barium, and lithium cations and the chloride, sulfate, fluoride, acetate, and phosphate anions. The response was linear (over the 20 microM-7 mM range) and reproducible (RSD = 3.4-4.9%; n = 10), with detection limits of 2.8 and 6.4 microM (for potassium and chloride, respectively). The advantages associated with the contactless conductivity detection, along with the low cost of the integrated PMMA chip/detection system, should enhance the power and scope of microfluidic analytical devices.

NASA Center JPL↗
DOE OSTI2023

Laser Scribing for Electrode Patterning of Perovskite Spectrometer-Grade CsPbBr 3 Gamma-ray Detectors

Making semiconductor radiation detectors that work at room temperature relies heavily on the deposition and pixelation of electrodes. Electrode patterning of perovskite solar cells widely implements laser scribing techniques, which is a convenient, scalable, and inexpensive technique. However, this method has not found its application in radiation detector patterning yet, and the question whether laser scribing can achieve high-quality patterns with minimum damage to a detector crystal and low interpixel cross-talk remains largely unanswered. To prove that laser scribing is a practical method for electrode patterning on perovskite CsPbBr 3 detectors, we use the material to create a variety of patterns. A very low lateral leakage current (60 nA at 10 V) and high mobility-lifetime product (9.7(3) x 10 -4 cm 2 /V) were observed between the pixel and the guard ring in tests of single-pixel devices with a separation of 200 or 100 μm between the central electrode and the guard ring. The 122 and 136 keV photopeaks in 57 Co gamma-ray spectra were very well resolved with an energy resolution of up to 6.1% at 122 keV. Finally, a further reduction in gap size to 50 mu m is conceivable, but more process optimization is needed.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗