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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 559 records · Page 31
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Investigation on capacity loss mechanisms of lithium-ion pouch cells under mechanical indentation conditions

Capacity loss was observed in Li-ion cells after mechanical deformation approaching the onset of internal short circuit (ISCr). In this paper, a series of indentation tests were carried out on commercial Li-ion cells of three capacities (500, 1500 and 2000 mAh). Both in-situ and ex-situ methods were used to investigate the mechanisms of indentation-induced capacity loss. We note after indentation test, the cell capacity reduced by 0.5%–6% of its original value. The incremental capacity (IC) analysis results showed that IC curves generally shifted to lower voltage region, indicating the increase in cell internal resistance. In addition, the fitting results of electrochemical impedance spectroscopy (EIS) indicated that mechanical indentation can result in a reduction in ohmic resistance and the increase in polarization resistance. Scanning electron microscopy (SEM) and X-ray computed tomography (XCT) results showed crushing of graphite, mud cracking of copper current collectors and enlarged pores in separator, which is proposed to be the main reasons for the increase in polarization resistance and permanent capacity loss. The rapid capacity loss due to mechanical abuse was compared with the long-term capacity fading.

25 ENERGY STORAGE↗
DOE OSTI2023

Molten Sodium Penetration in NaSICON Electrolytes at 0.1 A cm –2

High-conductivity solid electrolytes, such as the Na superionic conductor, NaSICON, are poised to play an increasingly important role in safe, reliable battery-based energy storage, enabling advanced sodium-based batteries. Coupled demands of increased current density (≥0.1 A cm –2 ) and low-temperature (<200 °C) operation, combined with increased discharge times for long-duration storage (>12 h), challenge the limitations of solid electrolytes. Here, we explore the penetration of molten sodium into NaSICON at high current densities. Previous studies of β"-alumina proposed that Poiseuille pressure-driven cracking (mode I) and recombination of ions and electrons within the solid electrolyte (mode II) are the two main mechanisms for Na penetration, but a comprehensive study of Na penetration in NaSICON is necessary, particularly at high current density. To further understand these modes, this work employs unidirectional galvanostatic testing of Na|NaSICON|Na symmetric cells at 0.1 A cm –2 over 23 h at 110 °C. Further, while galvanostatic testing shows a relatively constant yet increasingly noisy voltage profile, electrochemical impedance spectroscopy (EIS) reveals a significant decrease in cell impedance correlated with significant sodium penetration, as observed in scanning electron microscopy (SEM). Further SEM analysis of sodium accumulation within NaSICON suggests that mode II failure may be far more prevalent than previously considered. Further, these findings suggest that total (dis)charge density (mAh cm –2 ), as opposed to current density (mA cm –2 ), may be a more critical parameter when examining solid electrolyte failure, highlighting the challenge of achieving long discharge times in batteries using solid electrolytes. Together, these results provide a better understanding of the limitations of NaSICON solid electrolytes under high current and emphasize the need for improved electrode–electrolyte interfaces.

25 ENERGY STORAGE↗
NASA NTRS2010

Automated, Miniaturized Instrument for Measuring Gene Expression in Space

To facilitate astrobiological studies on the survival and adaptation of microorganisms and mixed microbial cultures to space environment, we have been developing a fully automated, miniaturized system for measuring their gene expression on small spacecraft. This low-cost, multi-purpose instrument represents a major scientific and technological advancement in our ability to study the impact of the space environment on biological systems by providing data on cellular metabolism and regulation orders of magnitude richer than what is currently available. The system supports growth of the organism, lyse it to release the expressed RNA, label the RNA, read the expression levels of a large number of genes by microarray analysis of labeled RNA and transmit the measurements to Earth. To measure gene expression we use microarray technology developed by CombiMatrix, which is based on electrochemical reactions on arrays of electrodes on a semiconductor substrate. Since the electrical integrity of the microarray remains intact after probe synthesis, the circuitry can be employed to sense nucleic acid binding at each electrode. CombiMatrix arrays can be sectored to allow multiple samples per chip. In addition, a single array can be used for several assays. The array has been integrated into an automated microfluidic cartridge that uses flexible reagent blisters and pinch pumping to move liquid reagents between chambers. The proposed instrument will help to understand adaptation of terrestrial life to conditions beyond the planet of origin, identify deleterious effects of the space environment, develop effective countermeasures against these effects, and test our ability to sustain and grow in space organisms that can be used for life support and in situ resource utilization during long-duration space exploration. The instrument is suitable for small satellite platforms, which provide frequent, low cost access to space. It can be also used on any other platform in space, including the ISS. It can be replicated and used with only small modifications in multiple biological experiments with a broad range of goals in mind.

Pohorille, A.↗
NASA NTRSDate not supplied

A materials-informatics based study of solid electrolytes and protective coatings for Li batteries

All-solid-state batteries with Li metal anode can address the safety issues surrounding traditional Li-ion batteries as well as the demand for higher energy densities. However, the development of solid electrolytes and protective coatings simultaneously possessing high ionic conductivity and wide electrochemical stability has proven to be a challenge. Here, we present a data-driven approach to explore the Li compound space for promising solid electrolytes and coatings. This is accomplished through the generation of a large database of battery-related materials properties of Li compounds by computing Li+ migration barriers using bond-valence-based pair potentials, and stability windows using density functional theory energies. Using this database, we implement machine learning models that can accurately predict migration barriers and electrochemical stability windows for any new Li compound. Through feature engineering, we ensure that our models are both accurate and interpretable. We perform feature importance analysis on our models to highlight materials properties that can be tuned for future design of coatings/electrolytes. Our database and informatics approach provide a valuable tool for the rapid discovery of new solid-state battery chemistries.

Solid state batteries↗
DOE OSTI2020

Fast Determination of Lithium Content in Spent Cathodes for Direct Battery Recycling

Determination of the lithium ion content in cathode materials, which is currently performed by inductively coupled plasma mass spectrometry (ICP-MS), involves tedious procedures and error-prone preparation. This work introduces a new methodology to quickly determine the lithium content in spent cathode materials (LiNix Mny Coz O2, x + y + z = 1, NMC) using a thermalgravimetric analysis, which bypasses the use of ICP-MS and significantly reduces the cost and time required for determining the lithium content. Based on this new method, a new approach is developed to identify spent cathode materials suitable for direct relithiation recycling. Finally, these new methods have been applied to investigate the effectiveness of direct electrochemical-relithiation on recycling the spent cathodes, and provide insights for future development of direct battery materials recycling.

cathode recycling↗
NASA NTRS1973

Procedure for analysis of nickel-cadmium cell materials

Quality control procedures include analyses on electrolyte, active materials, and separators for nickel cadmium cell materials. Tests range from the visual/mechanical inspection of cells to gas sampling, electrolyte extract, electrochemical tests, and physical measurements.

Halpert, G.↗
DOE OSTI2023

Parasitic Effects in Impedance Spectrum of PEM Water Electrolysis Cells: Case Study of High-Frequency Inductive Effects

Electrochemical impedance spectroscopy (EIS) is a powerful tool to characterize and distinguish electrochemical, electrical, and diffusive processes in an electrolysis cell. The EIS response with small impedance (mΩ) depends on components and materials of the cell, but often also on the electrical setup, cables, and connectors, leading to incorrect conclusions about the performance of the electrolysis cells. These parasitic effects are assessed via a short-circuit measurement and confirmed to be external from the membrane electrode assembly (MEA). In the setup, the inductive characteristic is described by a modified inductive reactance and must be included in the equivalent circuit model (ECM) which is fitting the cell EIS spectra in operation (in situ). If points of the spectra showing inductive characteristic (below x-axis in Nyquist plot) are excluded from the ECM evaluation, an artificially increased ohmic resistance at high frequencies is obtained. In addition, considerations on other components of the ECM can be misleading and significantly incorrect. The only way to avoid that inductive behavior caused by the external setup is incorrectly assigned to the ECM describing properties of the MEA is to include the inductive effects in the ECM analysis of in situ EIS measurements.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2020

Electro-chemo-mechanical evolution of sulfide solid electrolyte/Li metal interfaces: operando analysis and ALD interlayer effects

Sulfide solid electrolytes (SE) show promise for high-performance solid-state batteries because of their high ionic conductivity and ease of processing. However, sulfide electrolytes have suffered from chemical and electrochemical instability against Li metal anodes. In this paper, we use a suite of in situ/operando microscopy and spectroscopy techniques to demonstrate that Al 2 O 3 interlayers deposited using atomic layer deposition (ALD) delay degradation at the Li/LGPS interface by modifying the solid electrolyte interphase (SEI) chemistry and morphology. Optical and scanning electron microscopy are used to rationalize the electrochemical response of the system, which is attributed to a delayed onset of mechanical degradation at the interface when ALD interlayers are used. Operando X-ray photoelectron spectroscopy demonstrates that the dynamic evolution of SEI chemistry is impacted by the presence of the ALD interlayer. In situ Auger spectroscopy and operando optical microscopy provide visual evidence of spatial heterogeneity of Li plating, which is attributed to the chemo-mechanical degradation of the ALD interphase. The implications of these observations provide valuable insights toward the development of robust interlayers for solid-state batteries.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Block copolymer-mediated synthesis of TiO2/RuO2 nanocomposite for efficient oxygen evolution reaction

Abstract An amphiphilic block copolymer, poly (styrene-2-polyvinyl pyridine-ethylene oxide), was used as a structure-directing and stabilizing agent to synthesize TiO 2 /RuO 2 nanocomposite. The strong interaction of polymers with metal precursors led to formation of a porous heterointerface of TiO 2 /RuO 2 . It acted as a bridge for electron transport, which can accelerate the water splitting reaction. Scanning electron microscopy, energy-dispersive X -ray spectroscopy, transmission electron microscopy, and X -ray diffraction analysis of TiO 2 /RuO 2 samples revealed successful fabrication of TiO 2 /RuO 2 nanocomposites. The TiO 2 /RuO 2 nanocomposites were used to measure electrochemical water splitting in three-electrode systems in 0.1-M KOH. Electrochemical activities unveil that TiO 2 /RuO 2 -150 nanocomposites displayed superior oxygen evolution reaction activity, having a low overpotential of 260 mV with a Tafel slope of 80 mVdec −1 . Graphical abstract

36 MATERIALS SCIENCE↗
DOE OSTI2020

From electricity to fuels: Descriptors for C 1 selectivity in electrochemical CO 2 reduction

Electrochemical reduction of carbon dioxide (CO 2 RR) over transition metals follows a complex reaction network. Here, we combine observations from experimental literature with a theoretical analysis of energetics to rationalize that not all intermediates in the reduction of CO 2 are formed through direct protonation steps. We derive a selectivity map for two-electron products (carbon monoxide (CO) and formate) on pure metal surfaces using only the CO and OH binding energies as descriptors. For the pure metals that are selective towards CO formation, the variation of the CO binding energy is sufficient to further subdivide the map into domains that predominantly form H 2 , CO, and more reduced products. Our analysis rationalizes experimentally observed product distributions in CO 2 RR across pure metal systems. Overall, we highlight the need for additional material screening descriptors for CO 2 R and the importance of considering competition from the elementary steps of the hydrogen evolution reaction.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Imaginary admittance and charge transfer resistance correlate to the physiological status of Shewanella oneidensis cultures in real time

Monitoring microbial activity is essential for industrial and environmental applications to proceed efficiently. To minimize time and labor-intensive monitoring, a new paradigm is required for in-situ, real time analysis. Since bioconversion of organics is accomplished by microorganisms through the oxidation of feedstocks linked to the reduction of electron acceptors, microorganisms can be viewed as electrochemical catalysts. In this respect, cell membranes have an electrical potential, which is analogous to a conventional capacitor and linked dynamically to cellular activity. Here, in this study, we demonstrate the use of electrochemical impedance spectrometry (EIS) and cyclic voltammetry (CV) for monitoring microbial metabolic activity in real time, in-situ. The effect of organic electron donors as a function of concentration to the physiological status of strains of Shewanella oneidensis was determined. In this study, the pyomelanin overproducer (S. oneidensis ΔhmgA) and the pyomelanin deficient mutant (S. oneidensis ΔmelA) were chosen due to different surface electrochemical characteristics along with differences in oxygen utilization efficiency. CV, relative admittance, phase shift and permittivity changed with growth status and correlated with electron flow from organic carbon sources and terminal electron acceptor availability. This work offers a novel and inexpensive approach to real time monitoring with the advantage of abundant data.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Efficacy of Stabilizing Calcium Battery Electrolytes through Salt-Directed Coordination Change

Achieving practical, high-energy-density calcium batteries requires controlling the stability of Ca 2+ electrolytes during calcium metal cycling. Because of the highly reactive nature of calcium, most typical electrolyte constituents are unstable, leading to electrode passivation and low Coulombic efficiency. Among various commercially available salts, calcium bis(trifluoromethylsulfonyl)imide (Ca(TFSI) 2 ) is attractive because of its oxidative stability and high solubility in a variety of solvents. However, this salt does not allow for calcium metal plating, and it has been proposed that TFSI – instability induced by Ca 2+ coordination is to blame. In this work, we test the ability of strongly coordinating Ca 2+ cosalts such as halides and borohydrides to displace TFSI – from the first coordination shell of Ca 2+ and thereby stabilize TFSI-based electrolytes to enable calcium plating. Through spectroscopic analysis, we find that the effectiveness of these cosalts at displacing the TFSI – anion is dependent on the solvent’s coordination strength toward Ca 2+ . Surprisingly, electrochemical calcium deposition behavior is not correlated to the population of bound or free TFSI – . Instead, the nature of the coordination interaction between Ca 2+ and the cosalt anion is more important for determining stability. Our findings indicate that TFSI – anions are inherently unstable during calcium deposition even in the nominally free state. Furthermore, strategies aimed at eliminating the interactions of these anions with the electrode surface via interface/interphase design are required.

25 ENERGY STORAGE↗
DOE OSTI2022

Surface Immobilization of a Re(I) Tricarbonyl Phenanthroline Complex to Si(111) through Sonochemical Hydrosilylation

A sonochemical-based hydrosilylation method was employed to covalently attach a rhenium tricarbonyl phenanthroline complex to silicon(111). fac-Re(5-(p-Styrene)-phen)(CO) 3 Cl (5-(p-styrene)-phen = 5-(4-vinylphenyl)-1,10-phenanthroline) was reacted with hydrogen-terminated silicon(111) in an ultrasonic bath to generate a hybrid photoelectrode. Subsequent reaction with 1-hexene enabled functionalization of remaining atop Si sites. Attenuated total reflectance–Fourier transform infrared spectroscopy confirms attachment of the organometallic complex to silicon without degradation of the organometallic core, supporting hydrosilylation as a strategy for installing coordination complexes that retain their molecular integrity. Detection of Re(I) and nitrogen by X-ray photoelectron spectroscopy (XPS) further support immobilization of fac-Re(5-(p-styrene)-phen)(CO) 3 Cl. Cyclic voltammetry and electrochemical impedance spectroscopy under white light illumination indicate that fac-Re(5-(p-styrene)-phen)(CO) 3 Cl undergoes two electron reductions. Mott–Schottky analysis indicates that the flat band potential is 239 mV more positive for p-Si(111) co-functionalized with both fac-Re(5-(p-styrene)-phen)(CO) 3 Cl and 1-hexene than when functionalized with 1-hexene alone. XPS, ultraviolet photoelectron spectroscopy, and Mott–Schottky analysis show that functionalization with fac-Re(5-(p-styrene)-phen)(CO) 3 Cl and 1-hexene introduces a negative interfacial dipole, facilitating reductive photoelectrochemistry.

X-ray photoelectron spectroscopy↗
DOE OSTI2022

Modeling Framework to Analyze Performance and Structural Reliability of Solid Oxide Electrolysis Cells

Solid oxide electrolysis cells (SOEC) have been receiving significant attention recently because of their high energy efficiency and fast hydrogen production. In this study a multi-physics model to simulate the SOEC performance and structural reliability of a state-of-the-art planar SOEC design was developed. The electrochemical reactions, fluid dynamics, species transport, electron transfer, and heat transfer were modeled in the commercial computational fluid dynamics (CFD) software STAR-CCM+. The thermomechanical analysis and the associated structural reliability evaluations were conducted using the commercial finite element analysis software ANSYS. The electrochemistry model was validated by using the experimentally obtained current-voltage (I-V) characteristics of the electrode-supported SOECs. The reliability analysis using a risk-of-rupture approach showed low failure probabilities under standard operating conditions considered in this study. For cells operated at voltages well above a thermoneutral voltage, the reliability evaluations indicated a potential risk of cell failure, but the damage was concentrated locally in specific areas of the cell which typically do not lead to total loss of cell function. The presented approach provides insights for evaluating representative cell and stack performances and structural reliability without intensive testing and for developing optimally performing and structurally reliable SOECs for efficient hydrogen generation.

25 ENERGY STORAGE↗
NASA NTRS1990

Calorimetric determination of thermal parameters for the Li/BrCl in SOCl2 (BCX) chemistry

The heat capacity of a Li-BCX DD-cell was found to be dependent on its state of charge by drop calorimetry measurements. The method of drop calorimetry involves measuring the energy (joules) gained or lost from a sample that is transferred from a bath at temperature A to one at temperature B. The thermoneutral potential is defined as the cell potential where the cell electrochemical reactions are neither exothermic nor endothermic. A Hart scientific calorimeter system, Model No. S77XX, designed for heat conduction calorimetry and drop calorimetry was used. Calorimetric analysis yielded a thermoneutral potential of 4.14 volts and a cell heat capacity dependent on the state of charge.

Darcy, Eric C.↗
NASA NTRS2009

Processing and Probability Analysis of Pulsed Terahertz NDE of Corrosion under Shuttle Tile Data

This paper examines data processing and probability analysis of pulsed terahertz NDE scans of corrosion defects under a Shuttle tile. Pulsed terahertz data collected from an aluminum plate with fabricated corrosion defects and covered with a Shuttle tile is presented. The corrosion defects imaged were fabricated by electrochemically etching areas of various diameter and depth in the plate. In this work, the aluminum plate echo signal is located in the terahertz time-of-flight data and a threshold is applied to produce a binary image of sample features. Feature location and area are examined and identified as corrosion through comparison with the known defect layout. The results are tabulated with hit, miss, or false call information for a probability of detection analysis that is used to identify an optimal processing threshold.

Anastasi, Robert F.↗
NASA NTRSDate not supplied

Computationally Guided Development of Components for High Energy Density Solid-State Lithium-Sulfur Batteries

All electric vertical take-off and landing vehicles (eVTOL) for urban air mobility (UAM) concepts face numerous challenging technical barriers before their introduction into the consumer marketplace. The most challenging of these technical barriers to overcome is developing an energy storage system capable of meeting the rigorous aerospace safety and performance criteria1. The performance metrics for eVTOL craft, such as specific energy, specific power, and safety, exceed those of electric automobiles by a factor of two to four. Current state-of-the-art (SOA) lithium-ion batteries are incapable of meeting the key performance criteria of energy and safety for eVTOL. Therefore, next generation advanced chemistries and designs must be developed to meet required performance metrics for electric aviation2. Beyond lithium-ion chemistries, such as lithium-sulfur, show promise in their high energy, while limitations exist in their power and cyclability due to low electrical conductivity and high intermediate solubility in organic liquid electrolytes. Several strategies to overcome the low electrical conductivity involve the use of selenium as a dopant in the active sulfur material, along with the incorporation of 2-dimensional electron-conducting holey-graphene to improve the composite cathodes electronic conductivity. Furthermore, combining this chemistry with a solid-electrolyte avoids the components’ dissolution issues3. However, the development of composite solid-state cathodes is non-trivial as several components must be intimately mixed so that the active component has sufficient access to both electrons and lithium ions to undergo full electrochemical conversion. Mathematical modeling of battery components can assist experimental design through a robust and rigorous combination of computational modeling techniques covering multiple length scales. The objective is to leverage modern computational materials methods combined with battery multiphysics tools to develop radically advanced compatible cathode and electrolyte materials, build and test solid state lithium-sulfur cells and packs. A NASA-based cross-organizational team of high-powered experts combined integrated computational predictive modeling, fundamental chemistry analysis, advanced material science, and battery cell development to tackle this very challenging, multidisciplinary problem. This presentation will show a multiscale computational modeling approach that has produced a novel particle dynamics method called Solid Electrolyte Sphere Approximation Model (SESAM). SESAM modeling targets the 1-10 µm scale structures and provides electromechanical and grain interactions for predictive design guidelines for the manufacturing of solid-state components. Parameters such as particle size and volume fraction of the constituent materials were modeled and experimentally fabricated to optimize electrochemical performance through improved microstructure design. Experimental feedback was provided through ionic and electronic conductivity assessment and structural analysis of developed materials and cell components.

battery↗
DOE OSTI2023

Multielectrode electrochemical cell for in situ structural characterization of amorphous thin-film catalysts using high-energy X-ray scattering

A multielectrode-based electrochemical cell allows the structural characterization of an amorphous thin-film water oxidation catalyst under various electrochemical potentials using high-energy X-ray scattering and atomic pair distribution function (PDF) techniques. A multielectrode with five electrodes provides a sufficiently low background signal to enable high-energy X-ray scattering (HEXS) measurements and amplifies the extremely low HEXS signals from samples for high-resolution PDF analysis of in situ data from thin-film catalysts. Glassy carbon (GC) creates a relatively low intensity HEXS pattern and is used as a working electrode. Instead of a three-dimensional (3D) porous electrode architecture, the flat geometry of the electrode enables various deposition techniques to be used for the preparation of a highly conductive metal oxide layer. PDF analysis demonstrates high spatial resolution for a 230 nm thick amorphous iridium oxide film deposited on two roughened 60 µm thick GC electrodes. The PDF analysis resolves the domain size and distinguishes changes in fine structure which are directly correlated with the structure and function of the catalysts. In conclusion, the results bring the opportunity to analyze the structure of nanometre-scale amorphous thin-film catalysts in an electrolyte-compatible and compact 3D-printed electrochemical cell in a three-electrode configuration.

36 MATERIALS SCIENCE↗