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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 451 records · Page 25
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Salt‐in‐Salt Reinforced Carbonate Electrolyte for Li Metal Batteries

Abstract The instability of carbonate electrolyte with metallic Li greatly limits its application in high‐voltage Li metal batteries. Here, a “salt‐in‐salt” strategy is applied to boost the LiNO 3 solubility in the carbonate electrolyte with Mg(TFSI) 2 carrier, which enables the inorganic‐rich solid electrolyte interphase (SEI) for excellent Li metal anode performance and also maintains the cathode stability. In the designed electrolyte, both NO 3 − and PF 6 − anions participate in the Li + ‐solvent complexes, thus promoting the formation of inorganic‐rich SEI. Our designed electrolyte has achieved a superior Li CE of 99.7 %, enabling the high‐loading NCM811||Li (4.5 mAh cm −2 ) full cell with N/P ratio of 1.92 to achieve 84.6 % capacity retention after 200 cycles. The enhancement of LiNO 3 solubility by divalent salts is universal, which will also inspire the electrolyte design for other metal batteries.

25 ENERGY STORAGE↗
DOE OSTI2020

Enabling high areal capacity for Co-free high voltage spinel materials in next-generation Li-ion batteries

The rapidly growing technological demand for lithium-ion batteries has prompted the development of novel cathode materials with high energy density, low cost, and improved safety. High voltage spinel, LiNi 0.5 Mn 1.5 O 4 (LNMO), is one of the most promising candidates yet to be commercialized. The two primary obstacles for this material are the inferior electronic conductivity and fast capacity degradation in full cells due to the high operating voltage. By systematically addressing these limitations, we successfully develop a thick LNMO electrode with areal capacity loadings up to 3 mAh·cm –2 . The optimized thick electrode is paired with a commercial graphite anode at both the coin cell and pouch cell level, achieving a full cell capacity retention as high as 72% and 78%, respectively, after 300 cycles. We attribute this superior cycling stability to careful optimizations of cell components and testing conditions, with a specific focus improving electronic conductivity and high voltage compatibility. These results suggest precise control of materials quality, electrode architecture and electrolyte optimization can soon support the development of a cobalt-free battery system based on a thick LNMO cathode (>4 mAh·cm 2 ), which will eventually meet the needs of next-generation Li-ion batteries with reduced cost, improved safety, and assured sustainability.

25 ENERGY STORAGE↗
DOE OSTI2011

Sandwich-Type Functionalized Graphene Sheet-Sulfur Nanocomposite for Rechargeable Lithium Batteries

A sandwich structured graphene sheet-sulfur (GSS) nanocomposite was synthesized as the cathode material for lithium-sulfur batteries. The structure has a layer of graphene stacks and a layer of sulfur nanoparticles integrated into a three-dimensional architecture. This GSS nanoscale layered composite, making use of the efficient physical and electrical contact between sulfur and the large surface area, highly conductive graphene, provides a high loading of active materials of ~70 wt%, a high tape density of ~0.92 g∙cm-3, and a high power with a reversible capacity of ~505 mAh∙g-1 (~464 mAh∙cm-3) at a current density of 1,680 mA∙g-1 (1C). When coated with a thin layer of cation exchange Nafion film, the migration of dissolved polysulfide anions from the GSS nanocomposite was effectively alleviated, leading to a good cycling stability of 75% capacity retention over 100 cycles. This sandwich-structured composite conceptually provides a new strategy for designing electrodes in energy storage applications.

25 ENERGY STORAGE↗
DOE OSTI2019

Structure, Morphology, and Mechanical Properties of AlCrN Coatings Deposited by Cathodic Arc Evaporation

AlCrN coatings were deposited on steel substrates (HS6-5-2) using cathodic arc evaporation. The effect of nitrogen pressure on the properties of CrAlN coatings formed from Al{sub 80}Cr{sub 20} cathode, such as chemical and phase composition of the coatings, surface morphology, deposition rate, hardness and adhesion to the substrate, and friction and wear were investigated. The coating deposited at nitrogen pressure of 3 Pa shows the highest deposition rate. The roughness parameter Ra of the coating surface decreases with increasing nitrogen pressure during its formation. The test results showed that the AlCrN coatings deposited under nitrogen pressure in the range from 1 to 5 Pa show similar hardness for all the coatings, which is around 17 GPa. The increase in the negative bias voltage of the substrate during the formation of the coating deteriorates its adhesion to the substrate, although the wear rate is rather good, about 1.4 × 10{sup −7} mm{sup 3}/Nm. The coatings deposited at nitrogen pressure of 3-4 Pa are characterized by the highest critical load, 95 N. Despite worse adhesion, these coatings are characterized by high resistance to wear, the wear rate is about 1.4 × 10{sup −7} mm{sup 3}/Nm.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Face-centered tetragonal (FCT) Fe and Co alloys of Pt as catalysts for the oxygen reduction reaction (ORR): A DFT study

Proton exchange membrane fuel cells (PEMFCs) are promising candidates for alternate energy conversion devices owing to their various advantages including high efficiency, reliability, and environmental friendliness. The performance of PEMFCs is fundamentally limited by the sluggish kinetics of the oxygen reduction reaction (ORR) at the cathode. Various studies have addressed myriads of Pt-based alloys as potential catalysts for ORR. However, most of these studies only focus on the cubic-structured Pt-based alloys which require further improvements especially in terms of stability and required loading. We perform first-principle density functional theory calculations to explore Fe and Co alloys of Pt in a different face centered tetragonal (L1 0 ) geometry as potential catalysts for ORR. The work focuses on understanding the reaction mechanism of ORR by both dissociative and associative mechanisms on L1 0 –FePt/Pt(111) and L1 0 –CoPt/Pt(111) surfaces. The binding pattern of each reaction intermediate is studied along with the complete reaction free energy landscape as a function of Pt overlayers. The L1 0 –FePt/Pt(111) and L1 0 –CoPt/Pt(111) surfaces show higher calculated surface activity for ORR as compared to the native fcc Pt(111) surface. The decrease in the required overpotential (η) for the alloys with respect to the unstrained Pt(111) surface is found to be in the range (0.04 V–0.25 V) assuming the dissociative mechanism and (0.02 V–0.10 V) assuming the associative mechanism, where the variation depends on the thickness of Pt overlayers. We further correlate the binding behavior of the reaction intermediates to the applied biaxial strain on the Pt(111) surface with the help of a mechanical eigenforce model. The eigenforce model gives a (semi-) quantitative prediction of the binding energies of the ORR intermediates under applied biaxial strain. The numerical values of the limiting potential (U L ) obtained from the eigenforce model are found to be very close to ones obtained from electronic structure calculations (less than 0.1 V difference). Finally, the eigenforce model is further used to predict the ideal equi-biaxial strain range required on Pt(111) surfaces for optimum ORR activity.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Characterization of PVD Cr, CrN, and TiN coatings on SiC

SiC ceramic matrix composites are a potential replacement for current light water nuclear reactor fuel cladding material. However, loss of fission gas via micro-cracks and corrosion remain an issue. Cathodic arc Cr, CrN, and TiN coatings were deposited on SiC tubes and plates to provide hermeticity and corrosion resistance. These coatings were characterized to determine as-deposited quality. Cross-sectional microscopy, X-ray diffraction, glow discharge optical emission spectroscopy, and scratch tests were performed to evaluate the purity, structure, and mechanical performance of the coatings. Nitride coatings had stable interfaces, but larger defects in the coatings as compared to the Cr coatings which showed cracking at the interface, but less deposition-induced defects. Despite the local state of the interface, the mechanical properties of the metallic coatings versus ceramic coatings enabled the Cr coatings to resist loads three times that of the nitride coatings during scratch tests. Finally, glow-discharge optical emission spectroscopy showed that improvement in elemental purity is needed for future coatings.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Effect of isotropic and anisotropic porous microstructure on electrochemical performance of Li ion battery cathodes: An experimental and computational study

Liquid electrolyte mass transport is a major limitation affecting high-power Li ion batteries. Fast discharging causes Li salt depletion in the current collector region of the cathode which produces overpotential in the electrolyte and consequently a drop of cell voltage to below the cut-off voltage, especially at higher electrode thickness and discharge rate. In this study, through experiment and simulation, we have investigated the effect of electrode thickness, mass loading, discharge rate and tortuosity on electrolyte mass transport and final derived areal capacity and specific energy for electrodes having isotropic (normal tape casting) and anisotropic (freeze tape casting) porous microstructure. Furthermore, the macroporous channels in freeze tape cast electrodes facilitate Li salt transport and reduce the Li salt mass transport limitations even at high electrode thickness and discharge rates, and high electrode tortuosity. In our results, computer simulations show that freeze tape cast electrodes may be fully discharged up to 750 μm thickness at 1 C rate compared to 300 μm for normal tape cast electrodes with the same mass loading. Freeze tape cast electrodes also show stable maximum areal capacity for C rates about double the maximum C rates of their normal tape cast electrode counterparts with the same mass loading.

25 ENERGY STORAGE↗
DOE OSTI2020

Hydrous Nickel–Iron Turnbull’s Blue as a High-Rate and Low-Temperature Proton Electrode

Proton batteries are emerging as a promising solution for energy storage; however, their development has been hindered by the lack of suitable cathode materials. Herein, a hydrous Turnbull’s blue analogue (TBA) of Ni[Fe(CN) 6 ] 2/3 ·4H 2 O has been investigated as a viable proton cathode. Particularly, it shows an extremely high rate performance up to 6000 C (390 A g –1 ) at room temperature and delivers good capacity values at a low temperature of -40 °C in an aqueous electrolyte. The excellent rate capability is also amenable to high mass loadings of 10 mg cm –2 . Such fast and low-temperature rate behavior likely stems from the fast proton conduction that is afforded by the Grotthuss mechanism inside the TBA structure. Furthermore, advanced characterization, including in operando synchrotron X-ray diffraction (XRD), and X-ray absorption near-edge structure (XANES) were employed to understand the changes of crystal structures and the oxidation-states of metal elements of the electrodes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Lithium-Ion Battery Life Model with Electrode Cracking and Early-Life Break-in Processes

This paper develops a physically justified reduced-order capacity fade model from accelerated calendar- and cycle-aging data for 32 lithium-ion (Li-ion) graphite/nickel-manganese-cobalt (NMC) cells. The large data set reveals temperature-, charge C-rate-, depth-of-discharge-, and state of charge (SOC)-dependent degradation patterns that would be unobserved in a smaller test matrix. Model structure is informed by incremental capacity analysis that shows loss of lithium inventory and cathode-material loss as the dominant capacity fade mechanisms. The model includes terms attributable to solid-electrolyte interface (SEI) growth, electrode cracking, cycling-driven acceleration of SEI growth, and "break-in" mechanisms that slightly decrease or increase available Li inventory early in life. The study explores what mathematical couplings of these mechanisms best describe calendar aging, cycle aging, and mixed calendar/cycle aging. Various approaches are discussed for extracting relevant stress factors from complex cycling profiles to predict lifetime during real-world battery loads using models trained on constant-current laboratory test results. The complexity of the present human-driven model identification process motivates future work in machine learning to more widely search and statistically discern the optimal model that correctly extrapolates capacity fade based on physical knowledge.

25 ENERGY STORAGE↗
DOE OSTI2020

Novel Ionomers and electrode structures for improved PEMFC electrode performance at low PGM loadings (Final Report)

In this project, the objective is to develop new ORR electrocatalysts on optimized supports which can exceed all of the Department of Energy (DOE) 2020 targets listed in DE-FOA-0001412 directly relevant to the subtopic. This project’s approach is to develop novel, electrode-specific ionomers, and integrate them with state-of-the-art NSTF electrocatalyst powder to develop a cathode electrode achieving >= 044 A/mg PGM mass activity, <=30% mass activity loss during metal cycling, and <=0.125 g PGM /kW performance under DOE testing protocols. Ionomer O 2 permeability and proton conductivity will be increased by up to 1.5X over the baseline 3M800 perfluorosulfonate (PFSA) ionomer to enhance cathode electrode performance. Integration of cathode NSTF powder into an ionomer-containing electrode will increase the surface enhancement factor (SEF) to >=40 cm 2 PGM /cm 2 GEO allowing NSTF containing cathodes to exceed DOE MEA robustness targets. This report summarizes this project’s progress towards meeting the stated objectives and includes a summary of significant findings, conclusions, and developments over the entire project period from Oct. 1 st 2016 – Jan. 31 st 2020. This work has overcome key operation robustness issues with classic NSTF electrodes, identified pathways to improved dispersed and dispersed NSTF cathode performance, developed novel ionomers with high bulk conductivity and oxygen permeability, demonstrated exceptional support-independent electrode activity, and significantly increased metal and support stability through ionomer development. At this point, Tufts, MTU and all 5 FCPAD national labs have been involved, and contributed to, the improvements, learning and achievements of this work. Over the course of this project, more than 50 grams of dispersed NSTF powder in 15 different configurations have been generated, paving the way for scaleup within 3M. These whiskers have been processed in multiple ways, including acid leaching, powder-annealed, and sonicated by various means. For Task 2, 27 different types of ionomers were tested, 19 of which were made for the first time during the course of this project. 377 electrode inks with both NSTF and metal-on-carbon catalysts with I/C ratios from 0.2 to 1.2 were generated and mostly coated on a 3M pilot manufacturing line resulting in more than 700 different electrode types.

08 HYDROGEN↗
DOE OSTI2014

Pulsed electron beam generation with fast repetitive double pulse system

Longer duration high voltage pulse (∼ 100 kV, 260 ns) is generated and reported using helical pulse forming line in compact geometry. The transmission line characteristics of the helical pulse forming line are also used to develop fast repetition double pulse system with very short inter pulse interval. It overcomes the limitations caused due to circuit parameters, power supplies and load characteristics for fast repetitive high voltage pulse generation. The high voltage double pulse of 100 kV, 100 ns with an inter pulse repetition interval of 30 ns is applied across the vacuum field emission diode for pulsed electron beam generation. The electron beam is generated from cathode material by application of negative high voltage (> 100 kV) across the diode by explosive electron emission process. The vacuum field emission diode is made of 40 mm diameter graphite cathode and SS mesh anode. The anode cathode gap was 6 mm and the drift tube diameter was 10 cm. The initial experimental results of pulsed electron beam generation with fast repetitive double pulse system are reported and discussed. (author)

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

Improving Cost and Efficiency of the Scalable Solid Oxide Fuel Cells Power System

The objective of this project was to design and develop a 20kW range small-scale solid oxide fuel cells (SOFC) power system for applications such as data centers and commercial buildings. The original plan included a 5,000 hours demonstration and a Techno-Economic Analysis (TEA) which were dropped as part of project termination. The original project plan was to use a stack with a cross-flow cell design which had previously been tested for 500 hours at a community college in Malta, NY. However, it was decided to move to the advanced R-SOFC co-flow cell developed under Department of Energy Award DE-FE0031971. The advanced cell design has the advantage of a larger active area for the same manufacturing footprint which results in fewer required cells for the same stack power, hence a higher volumetric power density (kW/L) and lower cost per kW than the original cross-flow cell design. A full SOFC system Simulink model was developed and calibrated with testing data from a fuel cell stack and BOP (balance of plant) components. The simulation results from the calibrated model showed an acceptable match with the experimental data. A structural analysis conducted for various load scenarios indicated no high stress areas for all spatial directions. Major electrical system components were acquired, built and successfully tested. System sensors were verified and validated against controls. Safety checks, a diagnostic check, PID tuning, and control software commissioning tasks were also conducted. The power electronics prototype was delivered and trial testing completed. Balance of Plant component testing and simulation work was conducted to characterize Reformer-Heat Exchanger heat transfer and backpressure and reformer catalyst methane conversion and product selectivity. Simulations were conducted to design the Anode and Cathode fluid passages and size the air-air and fuel-fuel heat exchangers. A Burner operation map was created from test data and the Anode Gas Recirculation blower was tested to evaluate its durability. The SOFC system used a horizontal style design where components sit directly on a casting with a direct connection to the skid. This design has efficient packaging and a small footprint with approximate dimensions of 750 mm x 700 mm x 1700 mm. An SOFC system was built and successfully tested at the Malta, NY facility The system for over 500 hours under load of which over 300 hours was at full load of 20 kW.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2014

Environmental burdens in the management of end-of-life cathode ray tubes

Highlights: • The paper deals with different management options for end-of-life CRTs. • The environmental burdens for disposal and recycling are presented. • Recycling treatments allows to gain benefits for the environment. • Further treatments for fluorescent powders determine CO{sub 2} credits. • More efforts should be directed towards recycling. - Abstract: We compared the environmental burdens in the management of end-of life cathode ray tubes (CRTs) within two frameworks according to the different technologies of the production of televisions/monitors. In the first case, CRT recycling is addressed to the recovery of the panel and funnel glass for the manufacturing of new CRT screens. In the second case, where flat screen technology has replaced that of CRT, the recycling is addressed to the recovery of the glass cullet and lead for other applications. The impacts were evaluated according to the problem-oriented methodology of the Institute of Environmental Sciences, Leiden University, Leiden, The Netherlands. Our data confirm that in both cases, the recycling treatment allows benefits to be gained for the environment through the recovery of the secondary raw materials. These benefits are higher for the “CRT technology” framework (1 kg CO{sub 2} saved per CRT) than for the “flat screen technology” (0.9 kg CO{sub 2} saved, per CRT, as the highest possible), mainly due to the high energy consumption for lead separation from the funnel glass. Furthermore, the recovery of yttrium from the fluorescent powders that are a residue of the recycling treatment would further improve the CO{sub 2} credit for both the frameworks considered, which would provide a further saving of about 0.75 kg CO{sub 2} per CRT, net of the energy and raw materials needed for the recovery. Overall, this study confirms that, even with a change in the destination of the recovered materials, the recycling processes provide a benefit for the environment: indeed the higher loads for the environment are balanced by avoiding the primary production of the recovered materials.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2023

3D–Integrated, Multi–Functional Carbon Fibers for Stable, High–Areal–Capacity Batteries

Increasing lithium-ion batteries' (LIBs) electrode areal capacity can boost energy density and lower manufacturing costs, but faces challenges in manufacturing, rate performance, and cycling stability. A conductive framework made of commercial micro-sized carbon fibers (Cfs) is presented that serves as a host for both the LiNi 0.5 Mn 0.3 Co 0.2 O 2 (NMC 532) cathode and Cfs anode. The Cf framework has multiple functions that offer high electronic conductivity (270 mS cm –1 ), low tortuosity (1.7), low Li + diffusion resistance (22 Ω), and high thermal conductivity (200 W mK –1 ). Additionally, the Cf-integrated electrodes can have an extremely high mass loading of NMC 532 (70 mg cm –2 ) with a theoretical capacity of 14 mAh cm –2 . Thus, the practical full cells assembled with the Cfs-enabled electrodes exhibit an initial areal capacity of 4.1 mAh cm –2 and capacity retention of 90.4% at 500 cycles at a cycling rate of C/3, 1.5 mA cm –2 . Data collected from the operando isothermal microcalorimetry suggest that full cells utilizing the Cf anode experience less heat release from side reactions compared to cells utilizing a conventional graphite anode. Finally, this present approach is scalable and cost-effective and can fabricate practical LIBs that boast high areal capacity, rate performance, and a lengthy cycling lifetime.

25 ENERGY STORAGE↗
DOE OSTI2014

Arc plasma generator of atomic driver for steady-state negative ion source

The paper reviews the results of development of steady-state arc-discharge plasma generator with directly heated LaB{sub 6} cathode. This arc-discharge plasma generator produces a plasma jet which is to be converted into an atomic one after recombination on a metallic plate. The plate is electrically biased relative to the plasma in order to control the atom energies. Such an intensive jet of hydrogen atoms can be used in negative ion sources for effective production of negative ions on a cesiated surface of plasma grid. All elements of the plasma generator have an augmented water cooling to operate in long pulse mode or in steady state. The thermo-mechanical stresses and deformations of the most critical elements of the plasma generator were determined by simulations. Magnetic field inside the discharge chamber was optimized to reduce the local power loads. The first tests of the steady-state arc plasma generator prototype have performed in long-pulse mode.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2015

Plasma sputtering robotic device for in-situ thick coatings of long, small diameter vacuum tubes

A novel robotic plasma magnetron mole with a 50 cm long cathode was designed, fabricated, and operated. The reason for this endeavor is to alleviate the problems of unacceptable resistive heating of stainless steel vacuum tubes in the BNL Relativistic Heavy Ion Collider (RHIC). The magnetron mole was successfully operated to copper coat an assembly containing a full-size, stainless steel, cold bore, RHIC magnet tubing connected to two types of RHIC bellows, to which two additional pipes made of RHIC tubing were connected. To increase the cathode lifetime, a movable magnet package was developed, and the thickest possible cathode was made, with a rather challenging target to substrate (de facto anode) distance of less than 1.5 cm. Achieving reliable steady state magnetron discharges at such a short cathode to anode gap was rather challenging, when compared to commercial coating equipment, where the target to substrate distance is 10's cm; 6.3 cm is the lowest experimental target to substrate distance found in the literature. Additionally, the magnetron developed during this project provides unique omni-directional uniform coating. The magnetron is mounted on a carriage with spring loaded wheels that successfully crossed bellows and adjusted for variations in vacuum tube diameter, while keeping the magnetron centered. Electrical power and cooling water were fed through a cable bundle. The umbilical cabling system is driven by a motorized spool. Excellent coating adhesion was achieved. Measurements indicated that well-scrubbed copper coating reduced secondary electron yield to 1, i.e., the problem of electron clouds can be eliminated. Room temperature RF resistivity measurement indicated that a 10 μm copper coated stainless steel RHIC tube has a conductivity close to that of pure copper tubing. Excellent coating adhesion was achieved. The device details and experimental results are described.

36 MATERIALS SCIENCE↗