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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 1,009 records · Page 56
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Adsorption Processes during Electrochemical Atomic Layer Deposition of Gold

Electrochemical atomic layer deposition (e-ALD) technique offers a simple and effective "wet chemistry" approach enabling high-precision monolayer-by-monolayer deposition of metal films. The process of e-ALD of Au involves lead underpotential deposition (PbUPD) followed by its redox replacement by a Au monolayer. The time evolution of the deposit mass during "one-pot" Au e-ALD is known to exhibit a unique three-stage response that is presently not well understood. In this work, we probe this response using voltammetry, electrochemical quartz crystal microgravimetry (e-QCM), and chronoamperometry to unravel the underlying mechanistic events during Au e-ALD. Furthermore, the presence of adsorbed Au +3 -ligand complex(es) (Au-L) on the Au surface is established. In stage I of e-ALD, this Au-L adsorbed layer is reduced to Au while a Pb UPD adlayer is formed. In stage II, the Pb UPD adlayer undergoes spontaneous surface-limited redox replacement by nobler Au under open-circuit conditions. Finally, in stage III, re-adsorption of the Au-L occurs on the newly deposited Au. Quantitative analysis of the deposit mass transients obtained under a variety of conditions provides an estimate of the Au-L mass and its molecular weight.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Mechanically induced thermal runaway severity analysis of Li-ion batteries and continuous energy release monitoring

The large-scale deployment of Li-ion batteries in stationary energy storage and electrical vehicle applications demands a strong focus on safety, particularly on the thermal runaway risk and severity evaluation. A standardized single-side mechanical indentation test protocol was developed to induce an internal short-circuit (ISC) and evaluate cells' thermal runaway severity at different state of charge (SOC). The observed hazard severity (OHS in five categories) and evaluated scores in this work have a comprehensive consideration of each cell's capacity, initial voltage, SOC, temperature and voltage change, allowing a better evaluation of the cells' thermal runaway potential. This method was applied to about 200 Li-ion batteries in order to build an extensive thermal runaway database covering various SOCs, capacities and chemistries. In this study, we monitored the transitions of stored electrochemical energy and applied mechanical energy into both thermal energy and acoustic emissions (AE). The surface temperature and mechanical failures were monitored by infrared imaging and AE to capture critical events within battery cells throughout the mechanical indentation tests. Furthermore, the initial temperature maps can predict two types of follow-up events: thermal runaway or gradual heat release via conduction. Analyzing each cell's severity, AEs, and leveraging the evolving database offer insights into predicting occurrences of thermal runaway. The test method, thermal runaway severity evaluation and prediction, and the corresponding database provide battery designers, manufacturers, and end-users a clear overview of Li-ion batteries' thermal runaway potential under mechanical abuse, advancing the safety design of Li-ion batteries.

Acoustic emission↗
DOE OSTI2022

Probing the Influence of Multiscale Heterogeneity on Effective Properties of Graphite Electrodes

Graphite electrodes in the lithium-ion battery exhibit various particle shapes, including spherical and platelet morphologies, which influence structural and electrochemical characteristics. It is well established that porous structures exhibit spatial heterogeneity, and the particle morphology can influence transport properties. The impact of the particle morphology on the heterogeneity and anisotropy of geometric and transport properties has not been previously studied. Herein, this study characterizes the spatial heterogeneities of 18 graphite electrodes at multiple length scales by calculating and comparing the structural anisotropy, geometric quantities, and transport properties (pore-scale tortuosity and electrical conductivity). We found that the particle morphology and structural anisotropy play an integral role in determining the spatial heterogeneity of directional tortuosity and its dependency on pore-scale heterogeneity. Our analysis reveals that the magnitude of in-plane and through-plane tortuosity difference influences the multiscale heterogeneity in graphite electrodes.

25 ENERGY STORAGE↗
DOE OSTI2026

Graphene oxide precursor effects on 3D-printed carbon scaffolds

Manganese oxide (MnO 2 ), an earth-abundant material, is a promising component for energy storage devices, with uses in both pseudocapacitors and batteries. However, high MnO 2 loading often leads to reduced performance due to poor ion diffusion. 3D printing, particularly using the direct ink writing (DIW) technique, offers a solution by enabling the fabrication of electrodes with hierarchical porous structures and open channels that enhance mass transport and ion diffusion. Previous work demonstrated that 3D-printed graphene aerogels with MnO 2 coatings exhibited excellent electrochemical performance, even with thick electrodes, due to their optimized structure. Building on this work, the current study investigates the performance differences between aerogels developed using graphene oxide (GO) and reduced graphene oxide (rGO) as carbon precursors. Both materials were incorporated into thixotropic inks, 3D-printed into lattice structures, and carbonized. Despite expected similarities between the final graphene aerogel, rGO-based aerogels exhibited superior areal capacitance, compared to GO-based aerogels. These differences are attributed to the lower oxygen content and defect density of rGO, which influence its interaction with cellulose viscosifiers in the ink formulation. Brunauer–Emmett–Teller (BET) surface area analysis revealed that rGO aerogels exhibit a larger surface area and mesoporous structure, further enhancing their performance. When coated with MnO 2 , rGO-based aerogels maintained their superior capacitive behavior over GO-based aerogels. This study highlights the effect of carbon precursor on the end performance of graphene aerogels.

Materials science↗
DOE OSTI2022

The Dopamine Assisted Synthesis of MoO3/Carbon Electrodes With Enhanced Capacitance in Aqueous Electrolyte

A capacitance increase phenomenon is observed for MoO 3 electrodes synthesized via a sol-gel process in the presence of dopamine hydrochloride (Dopa HCl) as compared to α-MoO 3 electrodes in 5M ZnCl 2 aqueous electrolyte. The synthesis approach is based on a hydrogen peroxide-initiated sol-gel reaction to which the Dopa HCl is added. The powder precursor (Dopa) x MoO y , is isolated from the metastable gel using freeze-drying. Hydrothermal treatment (HT) of the precursor results in the formation of MoO 3 accompanied by carbonization of the organic molecules; designated as HT-MoO 3 /C. HT of the precipitate formed in the absence of dopamine in the reaction produced α-MoO 3 , which was used as a reference material in this study (α-MoO 3 -ref). Scanning electron microscopy (SEM) images show a nanobelt morphology for both HT-MoO 3 /C and α-MoO 3 -ref powders, but with distinct differences in the shape of the nanobelts. The presence of carbonaceous content in the structure of HT-MoO 3 /C is confirmed by FTIR and Raman spectroscopy measurements. X-ray diffraction (XRD) and Rietveld refinement analysis demonstrate the presence of α-MoO 3 and h-MoO 3 phases in the structure of HT-MoO 3 /C. The increased specific capacitance delivered by the HT-MoO 3 /C electrode as compared to the α-MoO 3 -ref electrode in 5M ZnCl 2 electrolyte in a −0.25–0.70 V vs. Ag/AgCl potential window triggered a more detailed study in an expanded potential window. In the 5M ZnCl 2 electrolyte at a scan rate of 2 mV s −1 , the HT-MoO 3 /C electrode shows a second cycle capacitance of 347.6 F g −1 . The higher electrochemical performance of the HT-MoO 3 /C electrode can be attributed to the presence of carbon in its structure, which can facilitate electron transport. Our study provides a new route for further development of metal oxides for energy storage applications.

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

Disentangling Memristive and Memcapacitive Effects in Droplet Interface Bilayers Using Dynamic Impedance Spectroscopy

The underlying principles for generating intelligent behavior in living organisms are fundamentally different from those in traditional solid-state circuits. Biomimetic neuromorphic equivalents based on biological membranes offer novel implementation of tunable plasticity and diverse mechanisms to control functionality. Here, dynamic electrochemical impedance spectroscopy (dEIS) to probe diphytanoylphosphatidylcholine (DPhPC) droplet interface bilayers (DIBs) to better understand the differences in molecular level structure/dynamics that give rise to hysteretic loops and neuromorphic, memelement behaviors in lipid bilayers in response to electrical biasing is used. Importantly, this system does not have ion-conducting channels and is, therefore, not expected to show memristive behavior. Surprisingly, both memristive and memcapacitive behaviors by measuring the time-dependent complex impedance of DPhPC DIBs are detected. Furthermore, it is shown that nonlinear memristance can originate from structural changes in the bilayer, affecting its dielectric properties. This novel dEIS application allows for the simultaneous analysis of the system's changing memristive and memcapacitive properties, which originate from different molecular restructuring processes. Moreover, and importantly, access to this type of information increases the number of neuromorphic processes supported simultaneously in a single two-terminal device.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Analysis of anion exchange membrane water electrolyzer performance and its evolution over time

Understanding water, evolved gas, and ionic transport in membrane-electrode-assemblies (MEAs) is essential for the development of high performance and durable anion exchange membrane water electrolyzers (AEMWEs). This study evaluates the MEA conditioning process, operating conditions, and short-term stability in a 1 M potassium hydroxide (KOH) electrolyte, focusing on the underlying transport phenomena. We observe a significant initial voltage loss in continuous cell operation, which could be associated with gas bubble accumulation, transport layer or flow field passivation, and changes in the catalyst oxidation state. Further, we investigate the effects of materials and operational configurations, including the membrane type and thickness, and the electrolyte flow rate, including KOH being fed to both electrodes as well as to the anode only. Furthermore, the effect of membrane drying temperature on ex situ as well as in situ electrochemical performance is evaluated. Finally, we discuss 700 h of AEMWE operation at 1 A/cm 2 , highlighting the underlying degradation phenomena.

25 ENERGY STORAGE↗
DOE OSTI2025

Using Light to Enhance Charge Transfer in Battery Materials: Increasing Charging Rates in LiNi 0.5 Mn 1.5 O 4

Electrochemical, spectroscopic, and computational studies on the interplay between light perturbation and coupled electron and Li-ion transfer in LiNi 0.5 Mn 1.5 O 4 (LNMO) cathodes identify that photon perturbation moves the system out of equilibrium, increases entropy, lowers the impedance of the battery, and increases the charging capacity by at least 15% during fast charging by promoting the oxidation of Ni 3+ to Ni 4+ . Here, the correlation with density functional theory calculations points out that oxidation of Ni 3+ faces a 30% higher barrier compared with the oxidation of Ni 2+ and hence exhibits greater responses to the energy transferred from photons. Structural analysis elucidates that photon energy also assists the transition of LNMO from the Jahn−Teller distorted asymmetric lattice with Ni 3+ to the nondistorted Ni 4+ . Synergistically, photons energize the removal of electrons from Ni 3+ and create photoinduced Ni 4+ intermediates, followed by the removal of Li + with almost two times faster diffusion rates.

5 V spinel↗
DOE OSTI2022

Initiating a Roadmap for Solar Fuels R&D: Imagining Beyond Thermochemical Cycles

Sandia National Laboratories in collaboration with the National Renewable Energy Laboratory outline a framework for developing a solar fuels roadmap based on novel concepts for hybridizing gas-splitting thermochemical cycle s with high-temperature electro chemical steps. We call this concept SoHyTEC, a Solar Hybrid Thermochemical-Electrochemical Cycle. The strategy focuses on transforming purely thermochemical cycles that split water (H 2 O) and carbon dioxide (CO 2 ) to produce hydrogen (H 2 ) and carbon monoxide (CO) , respectively, the fundamental chemical building blocks for diverse fuels and chemicals , by substituting thermochemical reactions with high-temperature electrochemical steps. By invoking high-temperature electrochemistry, the energy required to complete the gas-splitting cycle is divided into a thermal component (process temperature) and an electrical component (applied voltage). These components, sourced from solar energy, are independently variable knobs to maximize overall process efficiency. Furthermore, a small applied voltage can reduce cycle process temperature by hundreds of degrees , opening the door to cost-effective solar concentrators and practical receiver/reactor de signs. Using the SoHyTEC concept as a backdrop, we outline a framework that advocates developing methods for automating information gathering, critically evaluating thermochemical cycles for adapting into SoHyTEC, establishing requirements based on thermodynamic analysis, and developing a model-based approach to benchmarking a SoHyTEC system against a baseline concentrating solar thermal integrated electrolysis plant. We feel these framework elements are a necessary precursor to creating a robust and adaptive technology development roadmap for producing solar fuels using SoHyTEC. In one example, we introduce high-temperature electrochemistry as a method to manipulate a fully stoichiometric two-step metal oxide cycle that circumvents costly separation processes and ultra-high cycle temperatures. We also identify and group water-splitting chemistries that are conceptually amenable to hybridization.

14 SOLAR ENERGY↗
NASA NTRS2001

Characterization of the electromechanical properties of EAP materials

Electroactive polymers (EAP) are an emerging class of actuation materials. Their large electrically induced strains (longitudinal or bending), low density, mechanical flexibility, and ease of processing offer advantages over traditional electroactive materials. However, before the capability of these materials can be exploited, their electrical and mechanical behavior must be properly quantified. Two general types of EAP can be identified. The first type is ionic EAP, which requires relatively low voltages (<10V) to achieve large bending deflections. This class usually needs to be hydrated and electrochemical reactions may occur. The second type is Electronic-EAP and it involves electrostrictive and/or Maxwell stresses. This type of materials requires large electric fields (>100MV/m) to achieve longitudinal deformations at the range from 4 - 360%. Some of the difficulties in characterizing EAP include: nonlinear properties, large compliance (large mismatch with metal electrodes), nonhomogeneity resulting from processing, etc. To support the need for reliable data, the authors are developing characterization techniques to quantify the electroactive responses and material properties of EAP materials. The emphasis of the current study is on addressing electromechanical issues related to the ion-exchange type EAP also known as IPMC. The analysis, experiments and test results are discussed in this paper.

actuators↗
NASA NTRS2016

Deformation of Cases in High Capacitance Value Wet Tantalum Capacitors under Environmental Stresses

Internal gas pressure in hermetic wet tantalum capacitors is created by air, electrolyte vapor, and gas generated by electrochemical reactions at the electrodes. This pressure increases substantially with temperature and time of operation due to excessive leakage currents. Deformation of the case occurs when the internal pressure exceeds pressure of the environments and can raise significantly when a part operates in space. Contrary to the cylinder case wet tantalum capacitors that have external sealing by welding and internal sealing provided by the Teflon bushing and crimping of the case, no reliable internal sealing exists in the button case capacitors. Single seal design capacitors are used for high capacitance value wet tantalum capacitors manufactured per DLA L&M drawings #04003, 04005, and 10011, and require additional analysis to assure their reliable application in space systems. In this work, leakage currents and case deformation of button case capacitors were measured during different environmental test conditions. Recommendations for derating, screening and qualification testing are given. This work is a continuation of a series of NEPP reports related to quality and reliability of wet tantalum capacitors.

Tantalum Capacitors↗
DOE OSTI2026

Bipolar Membrane Electrodialyzers as Flexible Demand Response Resources: Co-Optimization of Cost Savings and Product Formation

Bipolar membrane electro dialyzers (BPMED) are widely used for chemical production and processing, including in the emerging ocean alkalinity enhancement (OAE) industry. In this paper, we explore the potential of BPMED devices as flexible electrochemical loads within power system operations. Using a multi-objective optimization framework, we evaluate BPMED operation across 24-hour and monthly horizons to examine how dispatch strategies respond to electricity price and grid conditions. Simulation results show that altering the relative weights of the choices in the objective function strongly shape the operating patterns, with cost-focused strategies that suppress the operation during peak prices. Furthermore, we propose alternative formulations that optimize operations to achieve both cost savings and alignment with periods of lower grid-side carbon intensity (CI), as low grid-side CI is key to maximize OAE efficiency. Additionally, a detailed sensitivity analysis highlights the importance of device properties, where low area-specific resistance (ASR) of membrane and high current efficiency (CE) are observed to jointly unlock cost-effective operation. However, even modest shunt efficiency losses are observed to erode performance and decrease system value. Importantly, the analysis demonstrates that BPMED can serve as a controllable and flexible demand response resource, shifting load to support multiple grid-side objectives, including (but not limited to) renewable integration, alleviate peak demand, and provide co-benefits for system reliability. These findings underscore BPMED’s dual role as a process technology and a grid-supporting asset, pointing to promising pathways for operational optimization of multiple objectives.

Bhattacharya, Saptarshi (ORCID:0000000308902060)↗
DOE OSTI2024

Imprinted Micelle Integration into a Commercial Platform (Progress Report)

PNNL has successfully integrated a commercial aerosol detector and the imprinted micelle technology. The integrated systems have been shown to have a limit of detection between 33-47 particles with several options for data analysis presented that vary on computational requirements. It is possible to integrate these systems and receive response data on the second time scale. While more work is needed, these technologies are compatible, which opens up a large field of air sampling looking for specific contaminates.

36 MATERIALS SCIENCE↗
NASA NTRS1994

Investigation of the structure and dynamics of the ozone layer in the Eastern Arctic region during EASOE Campaign

Balloon measurements of the vertical distribution of ozone and aerosol were made at Dickson Island (73 deg N, 81 deg E), Kiruna (68 deg N, 20 deg E) and Heiss Island (81 deg N, 58 deg E) from December 1991 to March 1992. To acquire data on the seasonal variability of the vertical ozone distribution, electrochemical ozonesondes ECC-4A were flown three times a week. With ozonesondes on the same balloons, backscattersondes were flown on the average of two or three times per month. Using these instruments, altitude profiles of backscatter ratio were measured at two wavelengths centered at 490 nm and 940 nm. Additionally, at Heiss Island, Dickson, and Yakutsk (63 deg N, 130 deg E) regular total ozone measurements were obtained using Brewer spectrophotometers. Based on measurements of backscatter ratio it was found that after the Pinatubo eruption in June 1991 significant amount of stratospheric aerosols were formed and transported to the Arctic before the polar vortex was well developed. Analysis of ozone data has shown a deep decrease of ozone concentration in the lower stratosphere in times of intensive transportation of air masses from low latitudes to the polar region in the second half of January and also for some periods in February and March of 1992. When the values of backscatter ratio beta were more than 8-10 at a wavelength of 940 nm strong anticorrelation occurred between aerosol loading and ozone concentration in the lower stratosphere. At 50-70 deg N, the mean monthly values of total ozone in winter-spring 1992 proved to be much lower than the climatic mean values.

Khattatov, V.↗
DOE OSTI2020

Corrosion of AISI 310 and 316 in Molten Hydroxide Under Steam Electrolysis Conditions

Steam electrolyzers, utilizing molten hydroxide electrolyte, offers potential for improvement in electrochemical efficiency, cost reduction, use of conventional materials of construction and process scale up for large scale hydrogen production. Stainless steels, used for the fabrication of cell components (current collector, gas separator, wet seals, and manifolds) experience accelerated corrosion in the presence of molten hydroxide electrolyte in both oxidizing (anodic) and reducing (cathodic) atmospheres. In this study, the corrosion behavior of AISI 310 and 316 in hydroxide melt has been studied at 600°C for 50 h. Melt immersion tests revealed formation of the porous lithium iron oxide at the melt-oxide interface for both AISI 310 and 316. Inductively coupled plasma optical emission spectrometry (ICP-OES) analysis showed the presence of Cr in the electrolyte melt obtained from samples exposed to oxidizing atmosphere. Thermochemical analysis was performed to validate the experimental results.

corrosion↗
NASA NTRS1994

Broad features of surface ozone variations over Indian region

Surface ozone concentration at three Indian stations - New Delhi (28.6 deg N), Pune (18.5 deg N) and Thiruvananthapuram (formerly Trivandrum (8.3 deg N) - has been measured since 1973 with the help of an electrochemical continuous ozone recorder. These stations show diurnal, seasonal and annual cycles in surface ozone. Daily changes show that the minimum value occurs at sunrise and maximum in the afternoon. As regards seasonal variations, Thiruvananthapuram and Pune have a minimum value during monsoon season (June to August) while at New Delhi the minimum value occurs in January. However, New Delhi also records low ozone amount during monsoon season identical to the amounts show at Thiruvananthapuram and Pune. The annual cycles at these stations have been compared with similar measurements in the northern and southern hemispheres. The Indian measurements agree well with the annual cycles at these stations. Further, the analysis of the Indian data indicates that the major contribution in surface ozone comes from the natural sources like stratospheric-tropospheric exchange, turbulence, and mixing in the boundary layer; however, a small contribution from anthropogenic sources cannot be ruled out at Pune and probably at New Delhi, especially in winter and summer seasons.

Shende, R. R.↗
DOE OSTI2021

Using In Situ High-Energy X-ray Diffraction to Quantify Electrode Behavior of Li-Ion Batteries from Extreme Fast Charging

Extreme fast charging (XFC, =15 min charging time) of Li-ion batteries (LIBs) has been proposed as an immediate target to increase the commercial appeal of electric vehicles. However, XFC of LIBs is associated with the degradation of battery performance and safety concerns. Quantitative and simultaneous characterization of various components during cell degradation represents a major experimental challenge. In this work, we outline a methodology for the use of spatially resolved, high-energy X-ray diffraction as a quantitative, in situ method of mapping the degradation of LIBs. We use this approach to study the battery cell capacity loss, both locally (mm scale) and globally over the entire cell (cm scale). Specifically, our workflow allows us to quantify the total amount of plated Li on the anode, as well as its spatial correlation to the structural properties of the anode and cathode. The method complements existing optical methods to resolve the spatial heterogeneity of local degradation mechanisms such as Li plating and provides simultaneous insights into concomitant anode state-of-charge variability. We apply it to commercially relevant single-layer pouch cells with the graphite anode and the LiNi 0.5 Mn 0.3 Co 0.2 O 2 cathode. Our results show that Li plating occurs heterogeneously on the graphite anode and that it is spatially correlated to the extent of anode lithiation. In this work, we anticipate that the described workflow will allow for understanding multiscale degradation in energy-storage devices beyond LIBs, where quantitative analysis at a local and global length scale can be performed without the necessity to tear down the device, due to the applicability of high-energy X-rays to probe in situ degradation.

25 ENERGY STORAGE↗