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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 1,459 records · Page 81
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Cycle Design and Optimization of Pressure Swing Adsorption Cycles for Pre-Combustion CO 2 Capture

Novel pressure-swing adsorption (PSA) cycles were developed based on patented TDA AMS- 19 (activated carbon) adsorbent for pre-combustion CO 2 capture in integrated gasi cation combined cycle (IGCC) power plants. A variety of cycles comprising of counter-current blowdown, pressure equalization, steam purge and light product pressurization steps were designed and simulated using an in-house one dimensional detailed model. Full process opti- mization studies were performed for all cycles to evaluate their feasibility for pre-combustion CO 2 capture. The CO 2 purity and recovery Pareto fronts obtained using the multi-objective optimization were used to assess their ability to simultaneously achieve high CO 2 purity (>95%) and recovery (>90%). The cycles that achieved the purity-recovery (95%-90%) requirements were subjected to energy-productivity optimizations under the constraints of CO 2 purity and recovery. Three cycle designs were ranked in terms of lowest energy con- sumption at 95% CO 2 purities and 90% CO 2 recoveries. It was found that a 10-step cycle with three pressure equalization steps achieved a minimum energy consumption of 95.7 kWhe/tonne of CO 2 captured at a productivity of 3.3 mol CO 2 captured/m 3 adsorbent/s.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Managing Through Continuous Improvement: If it doesn’t challenge you, it won’t change you

The past 24 months has been one of non-stop continuous improvement – every month, every week, every day, and every hour. It has been filled with continuously re-examining and challenging business systems, work processes, and legacy culture. The journey was difficult, but well worth it. It began by examining the existing conditions in each organization and building the case for change. When we stepped back and looked at our processes, systems, tools, and performance objectively, we realized we were struggling with frequent organizational, resource, and schedule conflicts, work processes that were not well-defined or expert based, project delays were common, management methods were predominantly reactive, advanced planning was limited to the near-term, no integration in scheduling across organizations, limited to no performance metrics to measure and manage performance, and internal and external customers did not feel like we were meeting their quality and performance expectations. It was a wake-up call. Change began at the top with a change leadership with where a new vision, expectations, and commitment were established. Leaving no stone left unturned, every aspect of the business was challenged which opened up communication and exposed the gaps. This was done in a ‘safe’ environment allowing for honest and solution-oriented discussion and action. The leadership team committed to managing through continuous improvement. The organizational structure was realigned to better align scope, responsibilities, execution, and customer focus. Visibility and transparency became the norm as higher levels of leadership and supporting organizations were invited to be part of regular strategy meetings and partnership discussion, effectively opening up the dialogue. This required a tremendous amount of trust and faith in a short period of time. Health assessments were conducted on each organization with specific lines of inquiry. These self-assessments helped to identify better define the scope of the organization and where targeted improvements were needed. Frequent organizational reviews were implemented to answer three fundamental questions: 1) What is your organization paid to do (scope)?, 2) How does your organization, or you, demonstrate that you are doing the job effectively?, and 3) What are you doing to improve your performance? To answer the first question, leaders defined the scope of the organization. Leaders were required to provide a path forward, with specific actions, where performance was not at expected levels internally at first and then from the stakeholders. Where business processes were not clearly understood, process maps were developed to provide this clarity for both those performing the work and those utilizing the process – the customers. To help answer the second question, numerous automated or semi-automated real-time, dynamic performance metrics were developed and implement to help leaders gain the visibility and demonstrate performance in six areas of operational excellence: safety, security, quality, effectiveness, productivity, and sustainability. Analysis of the performance provided windows of transparency and trends of work performance, work delays, cycle times, utilization, and much more that revealed many areas of improvement that were either not visible or desired to be visible. At the same time, they provided real-time progress which generated initial performance improvements by just beginning to measure. To address the third question, where systems did not support effectiveness of an existing or new process, then systems and tools were developed and implemented to drive the right behaviors and reinforce the processes. Tools and metrics were one of the major catalysts for culture shift and change. Risk assessments were leveraged into continuous improvement strategies, plans, and schedules. Targeted initiatives were identified and performed. Change and improvement was not, and is not, without significant and common challenges including limited/fixed budgets, resource availability, data access, natural resistance to change, and numerous other reasons or excuses – we called them ‘off-ramps’ and began to close them one-by-one. The results and outputs were significant and impactful in each organization and across the business with increased productivity, efficiency, visibility, accountability, management, and performance. Stakeholder satisfaction also increased. Cost and time savings allowed to more continuous improvement efforts to be performed. The effort clearly provided clear and measurable return on investment and value. Efforts that once seemed impossible, not feasible, or not achievable were performed. Decades-long issues were solved. ‘Impossible things are simply those which so far have never been done’ said Elbert Hubbard. So what will the next year be for you and your organization? Are you satisfied with the ‘same ‘ol, same ‘ol?’ Will you fall into the complacency trap and believe that change is too difficult, too expensive, and not necessary (or any number of possible excuses) or will you make this year your year or continuous improvement (and every year thereafter…)? Remember – what you do today can improve all your tomorrows’ (Ralph Marston).

96 KNOWLEDGE MANAGEMENT AND PRESERVATION↗
DOE OSTI2023

Interfacial pressure improves calendar aging of lithium metal anodes

Lithium (Li) metal is a promising anode because its theoretical specific capacity is approximately ten times larger than graphite. However, Li anodes suffer from long-term capacity fade due to Li stranding (becoming electronically disconnected) and electrolyte decomposition. Applied interfacial pressure has been shown to improve Li anode cycling, likely due to reincorporating stranded or “dead” Li into the anode. Calendar aging can also lead to Li capacity loss due to electrolyte decomposition/Li corrosion and the formation of stranded Li. Some research suggests that calendar aging during cycling results in reversible capacity losses due to Li stranding and reconnection. We here investigate the effect of applied interfacial pressure on Li anode calendar aging during cycling with incorporated rest steps in a localized high-concentration electrolyte (LHCE) to understand if pressure can mitigate stranded Li formation during rest by manipulating the Li morphology. Pouch cells exhibit more stable cycling and denser Li deposits between 10 kPa and 1,000 kPa of applied pressure compared to no applied pressure. Despite drops in CE during periodic rest cycles, the average cumulative lost capacity and average coulombic efficiency (CE) of cells over 50 cycles show that cells aged with incorporated rest steps perform similarly to cells cycled without added rests. This similar average CE suggests that dead Li is largely responsible for drops in CE during rest rather than irreversible Li corrosion and that the dead Li can be reconnected in subsequent cycling. The addition of a lithiophilic ZnO coating to the Cu working electrode increases the adhesion and coverage of Li deposits at low pressures and improves CE during the first cycle.

25 ENERGY STORAGE↗
DOE OSTI2020

Regulated lithium ionic flux through well-aligned channels for lithium dendrite inhibition in solid-state batteries

The utilization of solid electrolyte (SE) to suppress lithium (Li) dendrites is promising but still far from satisfactory due to the inhomogeneous Li plating/stripping. In this paper, we demonstrated a novel strategy to inhibit Li dendrites via regulating Li-ion flux in SE by using vertically aligned channels. The ion-insulating walls facilitated uniform distribution of Li-ion flux through the channels, leading to a homogeneous Li deposition, thus alleviating Li dendrite formation. As a result, symmetric cells with this SE exhibited excellent long-term stability (1000 h) against Li metal. In addition, Li4Ti5O12 (LTO)/Li cell with the developed SE achieved good battery performance over 100 cycles. The mechanism for dendrite suppression was further investigated by phase-field simulation. This work provides a novel strategy by manipulating uniform Li-ion flux to fabricate SE to inhibit Li dendrites and facilitates the development of high-performance rechargeable Li batteries.

25 ENERGY STORAGE↗
DOE OSTI2022

Hydroxyl Conducting Hydrogels Enable Low-Maintenance Commercially Sized Rechargeable Zn–MnO2 Batteries for Use in Solar Microgrids

Zinc (Zn)–manganese dioxide (MnO2) rechargeable batteries have attracted research interest because of high specific theoretical capacity as well as being environmentally friendly, intrinsically safe and low-cost. Liquid electrolytes, such as potassium hydroxide, are historically used in these batteries; however, many failure mechanisms of the Zn–MnO2 battery chemistry result from the use of liquid electrolytes, including the formation of electrochemically inert phases such as hetaerolite (ZnMn2O4) and the promotion of shape change of the Zn electrode. This manuscript reports on the fundamental and commercial results of gel electrolytes for use in rechargeable Zn–MnO2 batteries as an alternative to liquid electrolytes. The manuscript also reports on novel properties of the gelled electrolyte such as limiting the overdischarge of Zn anodes, which is a problem in liquid electrolyte, and finally its use in solar microgrid applications, which is a first in academic literature. Potentiostatic and galvanostatic tests with the optimized gel electrolyte showed higher capacity retention compared to the tests with the liquid electrolyte, suggesting that gel electrolyte helps reduce Mn3+ dissolution and zincate ion migration from the Zn anode, improving reversibility. Cycling tests for commercially sized prismatic cells showed the gel electrolyte had exceptional cycle life, showing 100% capacity retention for >700 cycles at 9.5 Ah and for >300 cycles at 19 Ah, while the 19 Ah prismatic cell with a liquid electrolyte showed discharge capacity degradation at 100th cycle. We also performed overdischarge protection tests, in which a commercialized prismatic cell with the gel electrolyte was discharged to 0 V and achieved stable discharge capacities, while the liquid electrolyte cell showed discharge capacity fade in the first few cycles. Finally, the gel electrolyte batteries were tested under IEC solar off-grid protocol. It was noted that the gelled Zn–MnO2 batteries outperformed the Pb–acid batteries. Additionally, a designed system nameplated at 2 kWh with a 12 V system with 72 prismatic cells was tested with the same protocol, and it has entered its third year of cycling. This suggests that Zn–MnO2 rechargeable batteries with the gel electrolyte will be an ideal candidate for solar microgrid systems and grid storage in general.

25 ENERGY STORAGE↗
DOE OSTI2026

Impact of Lithium‐Free Borate Additives on the Cycle Life and Calendar Aging of Silicon‐Based Lithium‐Ion Batteries

Silicon-anode lithium-ion batteries (LIBs) suffer from limited cycle life and poor calendar life, constraining their large-scale commercialization. Integrating additives into electrolytes is a simple and cost-effective strategy to improve these aspects. The effects of lithium-free boron-based additives on cycling and calendar performance of high-loading Si-anode LIBs remain largely unexplored. In this work, the influence of five Li-free borate additives, each with distinct molecular structures and elemental compositions, is systematically investigated. All additives enhance cycle life to varying extents. Notably, the addition of 1 v/v% tri(2,2,2-trifluoroethyl) borate to the baseline electrolyte nearly doubles the cycle life at 50% state of health. This enhancement is attributed to three key factors. Specifically, borate additives 1) improve electrochemical activity, 2) act as anion receptors that interact with [PF6]- anions and carbonate solvents to reduce electrolyte decomposition, and 3) promote the formation of a stable and polymeric solid electrolyte interphase layer. Furthermore, these additives exhibited negligible impact in mitigating leakage current during a 180 h voltage-hold calendar-aging test, indicating their limited effect in calendar life. These findings provide insight into the role of Li-free borate additives in improving cycle life while addressing the knowledge gap regarding their influence on calendar aging.

Li, Defu↗
DOE OSTI2018

Fuel Testing for Sylvatex: Cooperative Research and Development Final Report, CRADA Number CRD-16-636

Sylvatex is a green nano-chemistry company that has developed a platform technology utilizing renewable, non-toxic inputs to create a stable nanoparticle that can be used in multiple applications. Their mission is to increase the use of renewables globally, to empower a cleaner and healthier future. The main application is a fuel technology product - MicroX - that utilizes proprietary knowledge to scale low-cost, cleaner-burning renewable diesel fuel and additives by using a co-location commercial model. The aspects of this project will include testing of two Sylvatex MicroX fuels on an engine dynamometer platform. Industry standard ultra-low sulfur diesel (ULSD) B3 fuel and a ULSD B20 will both be used for comparison of the Sylvatex fuels (U.S. standard diesel fuel at the pump contains an average of approximately 3% biodiesel; this is why B3 would be used as a baseline comparison). Sylvatex is currently using a prototype formulation (MicroX 1) that applies a high cost surfactant. An experimental formulation (MicroX 2) that uses lower cost materials is under development. The MicroX 1 will be blended at a 10% level into the B3 ULSD fuel and the MicroX 2 will be blended at a 10% level into both the B3 and the B20 ULSD fuels for study on the engine dynamometer test platform. All fuel blends will be tested over the FTP transient engine test cycle and a steady state ramped modal engine test cycle. Each test cycle will be performed a minimum of 3 times for each fuel. Tailpipe and/or engine out gaseous exhaust emissions (CO2, CO, NOx, THC, O2,), engine out PM emissions, and brake-specific fuel consumption rates will be evaluated for all test cycles.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2018

Improved electrochemical cycling stability of intercalation battery electrodes via control of material morphology

Using a model tunnel manganese oxide with the todorokite crystal structure (T-MnO 2 ), we reveal that controlling the morphology of the active material can improve the cycling stability of intercalation battery electrodes. The T-MnO 2 structure is built from tunnels that provide spacious 1D diffusion channels for charge-carrying ions. Taking advantage of the unique ability to synthesize T-MnO 2 in the form of both highly crystalline two-dimensional (2D) nanoplatelets and one-dimensional (1D) nanowires through a facile hydrothermal growth method, we investigated the effect of nanoscale particle dimensions on reversible battery cycling. Insertion of ions into the tunnels results in anisotropic expansion of the structure, making T-MnO 2 with different morphologies an excellent model platform to understand how intercalation-induced volume change, typically leading to the deterioration of the electrode performance over extended cycling, can be controlled through synthesis of targeted morphologies. T-MnO 2 nanowires showed not only significantly improved capacity retention but also substantially higher specific capacity than the T-MnO 2 nanoplatelets. The enhanced electrochemical properties of the nanowire electrodes could be attributed to the larger surface-to-volume ratio than that of nanoplatelets, resulting in higher contact area with electrolyte for the nanowires. Moreover, due to the smaller cross-sectional area of the nanowires, volume expansion and contraction perpendicular to the structural tunnels induced by reversible ion intercalation occurs in a more facile fashion. In this research we demonstrate that chemically controlling morphology and producing particles with nanostructure dimensionality replicating that of atomic structure (i.e., 1D morphology and 1D structure) makes it possible to enhance material performance.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
NASA NTRS1996

Single battery power subsystems: On-line reconditioning

The effect of on-line reconditioning (deep discharge) on a single, Nickel-Hydrogen spacecraft battery in GEO and LEO is considered. A life cycle test was performed in both GEO and LEO to study the effect of reconditioning on the battery's end of discharge voltage (EODV). The results of these tests show that: LEO on-line reconditioning increased the EODV (by approximately 15 cycles to maximum EODV) and the EODV lasted for approximately 300 cycles, but GEO on-line reconditioning decreased the EODV slightly during the first six days and increases significantly after the seventh day. Based on the available data from the life cycle test, it has been concluded that a long life and stable voltage is realizable with the baseline architecture (single battery, single bus) without the need for reconditioning.

Tobias, R. F.↗
NASA NTRS1974

Miniature sheathed thermocouples for turbine blade temperature measurement

An investigation was made of sheathed thermocouples for turbine blade temperature measurements. Tests were performed on the Chromel-Alumel sheathed thermocouples with both two-wire and single-wire configurations. Sheath diameters ranged from 0.25 to 0.76 mm, and temperatures ranged from 1080 to 1250 K. Both steady-state and thermal cycling tests were performed for times up to 450 hr. Special-order and commercial-grade thermocouples were tested. The tests showed that special-order single-wire sheathed thermocouples can be obtained that are reliable and accurate with diameters as small as 0.25 mm. However, all samples of 0.25-mm-diameter sheathed commercial-grade two-wire and single-wire thermocouples that were tested showed unacceptable drift rates for long-duration engine testing programs. The drift rates were about 1 percent in 10 hr. A thermocouple drift test is recommended in addition to the normal acceptance tests in order to select reliable miniature sheathed thermocouples for turbine blade applications.

Holanda, R.↗
DOE OSTI2025

HOLISTIC ENERGY EFFICIENCY ANALYSIS OF ELECTRIFIED OFF-HIGHWAY MATERIAL HANDLER: FROM DRIVE CYCLE CHARACTERIZATION TO POWERTRAIN, HYDRAULIC, AND THERMAL SYSTEM PERFORMANCE

Three complexities surrounding the operation and testing of hybrid electric, heavy-duty nonroad machines have been addressed experimentally and using 1D simulation. Their resolutions have been intertwined with the development of a prototype machine that was proven to reduce fuel consumption in excess of 20%. A real-world drive cycle that leveraged hydraulic cylinder position was developed and utilized to ensure accurate reproduction of hydraulic work between the baseline and hybrid machines, while simultaneously maintaining less than 5% RMS error in position for main load handling functions. The newly developed, machine-specific drive cycle also contributed towards making equivalent comparisons in energy consumption between machine types through composite performance metrics that were extrapolated over a typical shift duration. Lastly, this work addressed thermal management energy consumption, a topic of increasing popularity when discussing electrified vehicles, by proposing a 1.4% energy savings through special mechanization and control of cooling system components.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2018

Synergistic effect of hierarchical SnO2 nanorods/Fe2O3 hexahedrons with enhanced performance as lithium ion battery anodes

Highlights: • SnO{sub 2}-Fe{sub 2}O{sub 3} nanocomposites were fabricated by a two-step hydrothermal method. • SnO{sub 2}-Fe{sub 2}O{sub 3} nanocomposites show high capacity and excellent cycling stability. • The enhanced performances benefit from the synergistic effect of SnO{sub 2} and Fe{sub 2}O{sub 3}. • The reduced Fe nanoparticles facilitate the fully conversion reaction of SnO{sub 2}. - Abstract: Hierarchical SnO{sub 2}-Fe{sub 2}O{sub 3} nanocomposites composed of SnO{sub 2} nanorods and Fe{sub 2}O{sub 3} hexahedrons are successfully prepared by a two-step hydrothermal method. The lithium ion batteries (LIBs) based on as-synthesized products are fabricated to investigate their electrochemical performance. As an anode material for LIBs, SnO{sub 2}-Fe{sub 2}O{sub 3} nanocomposites deliver a high capacity of 1022 mAh g{sup −1} at 100 mA g{sup −1} after 100 cycles. The cycling stability and rate performance of the nanocomposites are significantly improved. The enhanced performances benefit from the synergistic effect of SnO{sub 2} nanorods and Fe{sub 2}O{sub 3} hexahedrons. The iron (Fe) nanoparticles reduced from Fe{sub 2}O{sub 3} not only facilitate the conversion reaction of SnO{sub 2}, resulting in the high capacity, but also increase the conductivity of the material. In addition, SnO{sub 2} serves as a matrix to protect Fe{sub 2}O{sub 3} from agglomeration, and the hierarchical structure effectively buffers volume changes, thus enhancing the cycling life of LIBs.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2022

Flow battery cleansing cycle to maintain electrolyte health and system performance

A method of cleansing a redox flow battery system may include operating the redox flow battery system in a charge, discharge, or idle mode, and responsive to a redox flow battery capacity being less than a threshold battery capacity, mixing the positive electrolyte with the negative electrolyte. In this way, battery capacity degradation following cyclic charging and discharging of the redox flow battery system can be substantially reduced.

Song, Yang↗