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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 667 records · Page 37
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

A hybrid numerical and machine learning framework for evaluating the performance of a 780 cm 2 aqueous organic redox flow battery

Aqueous organic redox flow battery (AORFB) is a promising cost-competitive technology for large-scale energy storage. Among existing work, the dihydroxyphenazine (DHP)-based AORFB has demonstrated high energy density and low capacity degradation in 10 cm2 cells during lab tests. However, its commercial-scale performance in more complex environments remains unknown, posing a barrier for commercialization. To address this gap, this work presents a comprehensive performance evaluation of a 780 cm 2 DHP-based AORFB by combining physics-based numerical model, machine learning (ML)-based surrogate models, and ML-derived sensitivity quantification. Specifically, we first select 12 key battery parameters that include 10 physicochemical quantities and 2 operation quantities, then select 6 performance metrics that include energy efficiency (EE), discharging capacity, charging energy, and power losses due to concentration, activation, and ohmic over-potentials. With such selection, 12800 combinations of the 12 parameters are subsequently generated using the Latin Hypercube Sampling method. These combinations, together with 38 pre-defined State of Charge, are then integrated to a validated AORFB model developed in COMSOL to compute the performance metrics. With both input parameters and performance metrics, 60 deep neural network (DNN) surrogate models are then trained to approximate the relationship between the 10 physicochemical quantities and 6 performance metrics at each flow rate and current density. Sensitivity scores are then calculated based on the DNN models. Two additional sensitivity analysis tools, i.e., MARS, and SHAP, are also used to cross-validate the sensitivity scores from the DNN. The results demonstrate that 1) the standard potential ranks the first in controlling EE and charging energy, 2) the membrane conductivity is most critical for power loss and EE, and 3) specific area and reaction rate control activation power loss.

25 ENERGY STORAGE↗
NASA NTRS1989

Statistical prediction with Kanerva's sparse distributed memory

A new viewpoint of the processing performed by Kanerva's sparse distributed memory (SDM) is presented. In conditions of near- or over-capacity, where the associative-memory behavior of the model breaks down, the processing performed by the model can be interpreted as that of a statistical predictor. Mathematical results are presented which serve as the framework for a new statistical viewpoint of sparse distributed memory and for which the standard formulation of SDM is a special case. This viewpoint suggests possible enhancements to the SDM model, including a procedure for improving the predictiveness of the system based on Holland's work with genetic algorithms, and a method for improving the capacity of SDM even when used as an associative memory.

Rogers, David↗
DOE OSTI2021

Stable bismuth-antimony alloy cathode with a conversion-dissolution/deposition mechanism for high-performance zinc batteries

Although a large number of intercalation cathode materials for aqueous Zn batteries have been reported, limited intercalation capacity precludes achieving a higher energy density. Here, for this work, we develop a high-performance aqueous Zn battery based on BiSb alloy (Bi 0.5 Sb 0.5 ) using a high-concentrated strong-basic polyelectrolyte. We demonstrate that a conversion-dissolution/deposition electrochemical mechanism (BiSb ↔ Bi + SbO 2 – ↔ Bi + SbO 3 – ↔ Bi 2 O 3 ) through in situ X-ray diffraction (XRD), Raman, and ex-situ X-ray photoelectron spectrometry (XPS) characterizations with the help of density functional theory calculations. The BiSb cathode delivers large capacity of 512 mAh g –1 at 0.3 Ag –1 and superior rate capability of 90 mAh g –1 even at 20 Ag –1 , and long-term cyclability with capacity retentions of 184 mAh g –1 after 600 cycles at 0.5 Ag –1 and 130 mAh g –1 after 1300 cycles at 1 Ag –1 . Remarkably, even at temperatures as low as –10 and –20 °C, capacities of 210 and 197 mAh g –1 are reserved at 1 Ag –1 , respectively. Moreover, the prepared pouch Zn//BiSb battery delivers a high energy density of 303 Wh kg –1 BiSb at 0.3 Ag –1 . When coupled with a high concentration polyelectrolyte, the Zn/BiSb battery exhibits an excellent performance over a wide temperature range (–40 to 40 °C). Our research reveals the metal cathode is promising for Zn batteries to achieve a high performance with the unique mechanism and alloys can be an effective approach to stabilize metal electrodes for cycling.

25 ENERGY STORAGE↗
DOE OSTI2012

U.S. Solar Holdings Final Technical Report

This report summarizes the work of the US Solar Thermal Storage LLC (“USSTS”) team on SandShifter subproject for Phase 2 of U.S. Department of Energy’s FOA #DE-FC36-08GO18155.005. This subproject develops a new-to-the-world, disruptive technology which leverages an abundant, inexpensive, and benign material, Sand, for application in Thermal Energy Storage (TES) in association with power generation from Concentrating Solar Thermal (CST) systems. Sand, as a standalone TES media, has a 10 to 25X cost per unit of storage capacity cost advantage over the prevailing technology, molten salt. The work summarized herein suggests that SandShifter, which has a non-linear cost curve favoring higher hours of storage, could likely achieve economics of $15 per kWh-th or less for several hours of storage in high temperature steam- or salt-as-HTF configurations with further technology development.

14 SOLAR ENERGY↗
DOE OSTI2015

AlF 3 Surface-Coated Li[Li 0.2 Ni 0.17 Co 0.07 Mn 0.56 ]O 2 Nanoparticles with Superior Electrochemical Performance for Lithium-Ion Batteries

For Li-rich layered cathode materials considerable attention has been paid owing to their high capacity performance for Li-ion batteries (LIBs). In our work, layered Li-rich Li[Li 0.2 Ni 0.17 Co 0.07 Mn 0.56 ]O 2 nanoparticles are surface-modified with AlF 3 through a facile chemical deposition method. The AlF 3 surface layers have little impact on the structure of the material and act as buffers to prevent the direct contact of the electrode with the electrolyte; thus, they enhance the electrochemical performance significantly. The 3 wt% AlF 3 -coated Li-rich electrode exhibits the best cycling capability and has a considerably enhanced capacity retention of 83.1% after 50 cycles. Moreover, the rate performance and thermal stability of the 3 wt% AlF3-coated electrode are also clearly improved. Finally, surface analysis indicates that the AlF 3 coating layer can largely suppress the undesirable growth of solid electrolyte interphase (SEI) film and, therefore, stabilizes the structure upon cycling.

25 ENERGY STORAGE↗
DOE OSTI2023

Heat capacity of microgram oxide samples by fast scanning calorimetry

Quantitative scanning calorimetry on microgram-sized samples opens a broad, new range of opportunities for studying the thermodynamic properties of quantity-limited materials, including those produced under extreme conditions or found as rare accessory minerals in nature. We calibrated the Mettler Toledo Flash DSC 2+ calorimeter to obtain quantitative heat capacities in the range 200–350 °C, using samples weighing between 2 and 11.5 μg. Our technique is applied to a new set of oxide materials to which it has never been used before, without the need for melting, glass transitions, or phase transformations. Heat capacity data were obtained for silica in the high pressure stishovite (rutile) structure, dense post-stishovite glass, standard fused quartz, and for TiO2 rutile. These heat capacities agree within 5%–15% with the literature values reported for rutile, stishovite, and fused SiO2 glass. The heat capacity of post-stishovite glass, made by heating stishovite to 1000 °C, is a newly reported value. After accurate calibrations, measured heat capacities were then used to calculate masses for samples in the microgram range, a substantial improvement over measurement in conventional microbalances, which have uncertainties approaching 50%–100% for such small samples. Since the typical uncertainty of heat capacities measured on 10–100 mg samples in conventional differential scanning calorimetry is typically 7% (1%–5% with careful work), flash differential scanning calorimetry, using samples a factor of 1000 smaller, increases the uncertainty of heat capacity measurements by a factor of <3, opening the door for meaningful measurements on ultra-small, high-pressure samples and other quantity-limited materials.

Instruments & Instrumentation↗
DOE OSTI2019

A 3D Lithiophilic Mo 2 N–Modified Carbon Nanofiber Architecture for Dendrite–Free Lithium–Metal Anodes in a Full Cell

The pursuit for high-energy-density batteries has inspired the resurgence of metallic lithium (Li) as a promising anode, yet its practical viability is restricted by the uncontrollable Li dendrite growth and huge volume changes during repeated cycling. Herein, a new 3D framework configured with Mo 2 N-mofidied carbon nanofiber (CNF) architecture is established as a Li host via a facile fabrication method. The lithiophilic Mo 2 N acts as a homogeneously pre-planted seed with ultralow Li nucleation overpotential, thus spatially guiding a uniform Li nucleation and deposition in the matrix. The conductive CNF skeleton effectively homogenizes the current distribution and Li-ion flux, further suppressing Li-dendrite formation. As a result, the 3D hybrid Mo 2 N@CNF structure facilitates a dendrite-free morphology with greatly alleviated volume expansion, delivering a significantly improved Coulombic efficiency of ≈99.2% over 150 cycles at 4 mA cm –2 . Symmetric cells with Mo 2 N@CNF substrates stably operate over 1500 h at 6 mA cm –2 for 6 mA h cm –2 . Furthermore, full cells paired with LiNi 0.8 Co 0.1 Mn 0.1 O 2 (NMC811) cathodes in conventional carbonate electrolytes achieve a remarkable capacity retention of 90% over 150 cycles. Finally, this work sheds new light on the facile design of 3D lithiophilic hosts for dendrite-free lithium-metal anodes.

25 ENERGY STORAGE↗
DOE OSTI2017

Scalable Synthesis and Multi-Electron Transfer of Aniline/Fluorene Copolymer for Solution-Processable Battery Cathodes

Here, the authors report the highly efficient, multigram-scale synthesis of an ester-functionalized, poly(aniline-co-fluorene) polymer. The excellent solubility and film-forming ability of this polymer facilitate its application as a reversible battery cathode. Electrochemical quartz crystal microbalance with dissipation monitoring confirms a multi-electron transfer process, resulting in a specific discharge capacity of 51 mAh g -1 and a high reversible doping level of 0.69. Galvanostatic cycling at 1 C demonstrates excellent electrode stability with a capacity retention of 95.2% after 100 cycles. Therefore, this work demonstrates a novel electroactive polymer that exemplifies how chemical functionality may be used to properly balance processability and electroactivity of macromolecular battery cathodes.

25 ENERGY STORAGE↗
DOE OSTI2020

Additive‐Free Aqueous MXene Inks for Thermal Inkjet Printing on Textiles

Abstract Direct printing of functional inks onto flexible substrates allows for scalable fabrication of wearable electronics. However, existing ink formulations for inkjet printing require toxic solvents and additives, which make device fabrication more complex, limit substrate compatibility, and hinder device performance. Even water‐based carbon or metal nanoparticle inks require supplemental surfactants, binders, and cosolvents to produce jettable colloidal suspensions. Here, a general approach is demonstrated for formulating conductive inkjet printable, additive‐free aqueous Ti 3 C 2 T x MXene inks for direct printing on various substrates. The rheological properties of the MXene inks are tuned by controlling the Ti 3 C 2 T x flake size and concentration. Ti 3 C 2 T x ‐based electrical conduits and microsupercapacitors (MSCs) are printed on textile and paper substrates by optimizing the nozzle geometry for high‐resolution inkjet printing. The chemical stability and electrical properties of the printed devices are also studied after storing the devices for six months under ambient conditions. Current collector‐free, textile‐based MSCs show areal capacitance values up to 294 mF cm −2 (2 mV s −1 ) in poly(vinyl alcohol)/sulfuric acid gel electrolyte, surpassing reported printed MXene‐based MSCs and inkjet‐printed MSCs using other 2D nanomaterials. This work is an important step toward increasing the functional capacity of conductive inks and simplifying the fabrication of wearable textile‐based electronics.

Uzun, Simge↗
DOE OSTI2022

Integrated reactor architecture of conductive network and catalytic nodes to accelerate polysulfide conversion for durable and high-loading Li-S batteries

The development of carbon-based heterogeneous framework host with synergistic catalytic and conductive effects for sulfur cathode is a promising strategy to realize high performance lithium sulfur batteries (LSBs). Here, an integrated reactor architecture with defective carbon nodes (IRA-DC) is designed for serving as high-loading (92.4 wt%) sulfur host. The hierarchical porous IRA-DC consists of untangled conductive carbon nanotube network and Co/N co-doped catalytic nodes with high dispersity. Therein the optimization of electric field distribution and homogenization of adsorption-catalysis sites offer the multi-electron conversion reaction of polysulfides with excellent kinetics and stability. The resultant IRA-DC/S cathode enables a high areal capacity of 8.86 mAh cm -2 under ultra-high sulfur loading (13.1 mg cm -2 ) and lean electrolyte (8 μL mg sulfur -1 ). It also displays a long-term cycling performance (1200 cycles at 1 C) and ultrahigh rate performance up to 20 C (with a capacity of 473.6 mAh g -1 ). In conclusion, this work provides an electrode building strategy by optimizing the environments of heterogeneous electrocatalysis and micro electric field to activate the polysulfide conversion efficiency and utilization of high-loading sulfur in monolithic sulfur-carbon cathodes.

25 ENERGY STORAGE↗
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 OSTI2020

Empirical characterization of vertical-tube inlets in hot-water storage tanks

Hot-water storage in residential and commercial tanks is of growing interest for peak-shifting the electrical demand associated with hot-water loads. How the water enters the tank can significantly affect the extraction efficiency of the storage. Vertical-tube inlets (VTIs) direct cold water into the tank. The VTI design influences whether large-scale mixing occurs, which can reduce the delivery capacity of the hot-water storage. In this work, the mixing at the VTI discharge was characterized by the eddy diffusivity factor (EDF) in an allometric curve fit to the ratio Re:Ri using inlet superficial velocities. The full experimental campaign tested VTI's with Re’s between 170 and 22,300 and Ri's between 0 and 376. Animated visualization of the experimentally measured data is provided, showing tank temperature evolution during inlet flows. The most predictive correlations for EDF are for VTI Re in the transition zone (i.e. ~2300 < Re < ~10,000) and at a Ri corresponding to a stably stratified tank (i.e. Ri > 5). For vertical-tubes that distribute cold water below the thermocline, increasing the EDF will decrease the stratification in a hot-water tank as EDF quantifies inlet mixing. Overall, the new correlations for VTIs can be used to design and model thermally-stratified storage tanks.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2019

Direct observation of MgO formation at cathode electrolyte interface of a spinel MgCo 2 O 4 cathode upon electrochemical Mg removal and insertion

Identifying a Mg 2+ insertion mechanism into Mg cathode is one crucial challenge of designing Mg batteries that own comparable specific energy to the lithium ion systems. Spinel Mg cathodes are attractive candidates mainly attributed to its high intercalation voltage and theoretical capacity, however, electrochemically removing Mg from its solid structure with identified capacity dedicated to actual reversible Mg intercalation introduce complications. Work presented here applies Scanning/Transmission Electron Microscopy with Energy Loss Spectroscopy and diffraction method to investigate the cathode electrolyte interface for a spinel MgCo 2 O 4 material electrochemically cycled in the presence of a non-aqueous, low water content Mg electrolyte. Findings at an atomic scale suggest a complete de-magnesiation is occurring for thin MgCo 2 O 4 particles upon electrochemical charging, but a vast majority of MgCo 2 O 4 shows formation of an amorphous MgO layer with a thickness of similar to ~10 nm at the cathode electrolyte interface. The amorphous MgO layer is directly jointed with the crystalline MgCo 2 O 4 at the outer edge of the cathode. Formation of MgO at the cathode electrolyte interface is believed to be the detrimental factor preventing further electrochemical cell cycling of MgCo 2 O 4 . A possible reaction pathway of intercalation-initiated surface conversion is proposed to explain reversible Mg insertion with MgCo 2 O 4 .

25 ENERGY STORAGE↗
DOE OSTI2016

Express and low-cost microwave synthesis of the ternary Chevrel phase Cu{sub 2}Mo{sub 6}S{sub 8} for application in rechargeable magnesium batteries

The ternary Chevrel phase Cu{sub 2}Mo{sub 6}S{sub 8} was successfully synthetized using a simple and cost-effective solid-state microwave-assisted reaction. While solid-state routes require days of high-temperature treatment under inert atmosphere, highly pure and crystalline Cu{sub 2}Mo{sub 6}S{sub 8} could be obtained in only 400 s from this precursor, the Chevrel binary phase Mo{sub 6}S{sub 8} was then obtained by copper removal through acidic leaching, and was evaluated as a positive electrode material for Mg-battery. The electrochemical performance in half-cell configuration shows reversible capacity exceeding 80 mAh/g, which is comparable to previous works carried out with materials synthesized by conventional high-temperature solid-state routes. - Graphical abstract: Ultrafast micro-wave synthesis of Chevrel phase Cu{sub 2}Mo{sub 6}S{sub 8} towards Mo{sub 6}S{sub 8} as positive electrode of Mg-battery. - Highlights: • Chevrel phase Cu{sub 2}Mo{sub 6}S{sub 8} is synthesized by fast microwave-assisted solid-state reaction. • Highly-pure and well-crystalline Cu{sub 2}Mo{sub 6}S{sub 8} is obtained. • Mo{sub 6}S{sub 8} obtained from leaching is tested as a positive electrode for Mg batteries.

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

Mesoporous aluminosilicate glasses: Potential materials for dye removal from wastewater effluents

Mesoporous amorphous sodium-aluminosilicate host matrices of composition Si{sub 1−x}Al{sub x}Na{sub x}O{sub 2}, 0.1 ≤ x ≤ 0.33, obtained by sol-gel methodology, have been used as sequestrating agents for the cationic dye Rhodamine 6 G (Rh6G) in solution. Favorable adsorption kinetics and a wide pH working range (4–10) as well as high sorption capacities for Rh6G render these materials potentially useful reagents for effective dye removal from wastewaters. While the experimentally realized sorption capacities fall significantly below the theoretical limits, used materials can be thermally re-cycled by pyrolizing the sequestrated dye molecules. Solid state NMR and BET measurements show that this process occurs under preservation of the materials' structural integrity, allowing it to be re-used multiple times. - Graphical abstract: Sorption of rhodamine dye by mesoporous sodium aluminosilicate. Display Omitted.

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

Triphase electrode performance adjustment for rechargeable ion batteries

Rechargeable batteries electrodes are mainly classical oxides with single structure, but their performance is insufficient to meet the growing energy storage needs of modern-society. Recently, composite-structure materials with great improvements in electrochemical performance have been developed. However, little research has been conducted on these materials with regard to adjusting their structures and further controlling their electrochemical performance. Herein, composite-structure Na 2/3 Ni 1/3–x Fe x Ti 2/3 O 2 (0 ≤ x ≤ 1/3) electrodes for sodium-ion batteries were designed on the basis of results from in-situ high-temperature X-ray diffraction. Triphase compositions of P2-Na 2/3 Ni 1/3 Ti 2/3 O 2 , tunnel-Na 2.65 Ti 3.35 Fe 0.65 O 9 , and tunnel-NaFeTiO 4 were prepared, and Na + insertion/extraction in different structures was observed using in-situ electrochemical X-ray diffraction. An optimum electrode with 46% P2-structure presented the best comprehensive performance: 105 mAh g –1 initial reversible capacity along with 86.5% capacity-retention after 1500 cycles. As a result, this work opens a new field for designing and adjusting composite electrodes for better electrochemical performance, not limited for sodium-ion batteries but also for other advanced battery-systems.

25 ENERGY STORAGE↗
DOE OSTI2022

Vacancy-Driven Disorder and Elevated Dielectric Response in the Pyrochlore Pb 1.5 Nb 2 O 6.5

Lone pair-driven distortions are a hallmark of many technologically important lead (Pb)-based materials. Here, the role of Pb 2+ in polar perovskites is well understood and easily manipulated for applications in piezo- and ferroelectricity, but the control of ordered lone pair behavior in Pb-based pyrochlores is less clear. Crystallographically and geometrically more complex than the perovskite structure, the pyrochlore structure is prone to geometric frustration of local dipoles due to a triangular arrangement of cations on a diamond lattice. The role of vacancies on the O' site of the pyrochlore network has been implicated as an important driver for the expression and correlation of stereochemically active lone pairs in pyrochlores such as Pb 2 Ru 2 O 6.5 and Pb 2 Sn 2 O 6 . In this work we report on the structural, dielectric, and heat capacity behavior of the cation- and anion-deficient pyrochlore Pb 1.5 Nb 2 O 6.5 upon cooling. We find that local distortions are present at all temperatures that can be described by cristobalite-type cation ordering, and this ordering persists to longer length scales upon cooling. From a crystallographic perspective, the material remains disordered and does not undergo an observable phase transition. In combination with density function calculations, we propose that the stereochemical activity of the Pb 2+ lone pairs is driven by proximity to O' vacancies, and the crystallographic site disorder of the O' vacancies prohibits long range correlation of lone pair-driven distortions. This in turn prevents a low-temperature phase transition and results in an elevated dielectric permittivity across a broad temperature range.

36 MATERIALS SCIENCE↗