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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 1,477 records · Page 82

Is Cu a stable electrode material in hybrid perovskite solar cells for a 30-year lifetime?

One grand challenge for long-lived perovskite solar cells is that the common electrode materials in solar cells, such as silver and aluminum or even gold, strongly react with hybrid perovskites. Here we report the evaluation of the potential of copper (Cu) as the electrode material in perovskite solar cells for long-term stability. In encapsulated devices which limit exposure to oxygen and moisture, Cu in direct contact with CH 3 NH 3 PbI 3 showed no reaction at laboratory time scales, and is predicted to be stable for almost 170 years at room temperature and over 22 years at the nominal operating cell temperature of 40 °C. No diffusion of Cu into CH 3 NH 3 PbI 3 has been observed after thermal annealing for over 100 hours at 80 °C, nor does Cu cause charge trap states in direct contact with CH 3 NH 3 PbI 3 after long-term thermal annealing or illumination. High performance devices with efficiency above 20% with Cu electrode retains 98% of the initial efficiency after 816 hours storage in ambient environment without encapsulation. Finally, the results indicate Cu is a promising low-cost electrode material for perovskite solar cells for long-term operation.

25 ENERGY STORAGE↗

Single step synthesis of rutile TiO{sub 2} nanoflower array film by chemical bath deposition method

Titanium oxide (TiO{sub 2}) nanostructures such as nanorod arrays, nanotube arrays and nanoflower arrays have been extensively investigated by the researchers. Among them nanoflower arrays has shown superior performance than other nanostructures in Dye sensitized solar cell, photocatalysis and energy storage applications. Herein, a single step synthesis for rutile TiO{sub 2} nanoflower array films suitable for device applications has been reported. Rutile TiO{sub 2} nanoflower thin film was synthesized by chemical bath deposition method using NaCl as an additive. Bath temperature induced evolution of nanoflower thin film arrays was observed from the morphological study. X-ray diffraction study confirmed the presence of rutile phase polycrystalline TiO{sub 2}. Micro-Raman study revealed the presence of surface phonon mode at 105 cm{sup −1} due to the phonon confinement effect (finite size effect), in addition with the rutile Raman active modes of B{sub 1}g (143 cm{sup −1}), Eg (442 cm{sup −1}) and A{sub 1}g (607 cm{sup −1}). Further, the FTIR spectrum confirmed the presence of Ti-O-Ti bonding vibration. The Tauc plot showed the direct energy band gap nature of the film with the value of 2.9 eV.

77 NANOSCIENCE AND NANOTECHNOLOGY↗

Inertia Estimation and Trend Analysis of the United States Power Grid Interconnections

The transition from conventional to modern power systems is causing an increase in integration of inverter-based resources (IBRs). This generally leads to a decrease in total system inertia, which in-turn increases the system’s rate-of-change-of-frequency (RoCoF) during disturbances. This poses a threat to the frequency stability of the system and may falsely trigger protective devices. To monitor system status and plan for integrating renewable energy sources like photovoltaic, wind, and energy storage systems, a realistic study of inertia estimation and analysis in the United States (US) over the past decade is needed. This paper uses field-measured phasor measurement unit (PMU) data collected throughout the US from 2013 to 2023 via the Frequency Monitoring Network (FNET/GridEye) operated by the University of Tennessee, Knoxville (UTK) and Oak Ridge National Laboratory (ORNL). The collected PMU frequency data is utilized to estimate the system inertia of the three US interconnections: Eastern, Western, and Texas. Various RoCoF time windows are investigated for estimating the inertia of each interconnection by maximizing the correlation coefficient between the measured RoCoF and power mismatch. The resulting inertia trends over the past decade show approximately a 6% decline in inertia in the Eastern interconnection, a 15% decline in inertia in the Western interconnection, and a 16% increase in inertia in Texas. Key insights into how inertia is changing amidst the complex energy landscape are extracted using the fuel mix trend data. This provides valuable information for future energy strategies and planning.

30 DIRECT ENERGY CONVERSION↗

Hyperspectral Polymer Solar Cells, Integrated Power for Microsystems

The purpose of this research is to address a critical technology barrier to the deployment of next generation autonomous microsystems – the availability of efficient and reliable power sources. The vast majority of research on microsystems has been directed toward the development and miniaturization of sensors and other devices that enhance their intelligence, physical, and networking capabilities. However, the research into power generating and power storage technologies has not keep pace with this development. This research leveraged the capabilities of RIT’s NanoPower Research Laboratories (NPRL) in materials for advanced lithium ion batteries, nanostructured photovoltaics, and hybrid betavoltaics to develop reliable power sources for microsystems.

14 SOLAR ENERGY↗

Large Scale Simulation Platform for NODES Validation Study

This report summarizes the Large Scale (LS) simulation platform created for the Eaton NODES project. The simulation environment consists of both wholesale market simulator and distribution simulator and includes the CAISO wholesale market model and a PG&E footprint of 25-75 feeders to validate the scalability under a scenario of 33% RPS in California with additional 17% of DERS coming from distribution and customers. The simulator can generate hourly unit commitment, 5-minute economic dispatch, and 4-second AGC regulation signals. The simulator is also capable of simulating greater than 10k individual controllable devices. Simulated DERs include water heaters, EVs, residential and light commercial HVAC/buildings, and residential-level battery storage. Feeder-level voltage regulators and capacitor banks are also simulated for feeder-level real and reactive power management and Vol/Var control.

24 POWER TRANSMISSION AND DISTRIBUTION↗

Electric Utility Industry Standards Landscape

The electric utility industry relies on robust communication protocols to manage complex electrical grid data. The inherent networked nature of electrical grids, coupled with the radial structure of the “last mile” portion delivering power to end-use customers, presents difficulties in describing electrical models using simple data constructs. The paper provides an overview of communication protocols that address electric utility data, including grid data, and classifies these protocols through identification key characteristics that make them suitable for different electric grid data domains. Because of their variety, grid edge devices and their associated dedicated protocols are assessed by groups: those primarily designed for energy production and storage, those related to flexible loads, and those related to electric vehicles. The intent of this report is to provide guidance for stakeholders to navigate the challenges posed by the numerous overlapping protocols available to address electric grid data. Although further industry review, refinement, and validation of the categorization of these protocols is recommended, the authors propose this categorization as a start to improve electric grid awareness and understanding. In addition, this report includes three recommended industry actions regarding protocols to improve communications on the electric grid.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗

Design of highly active and durable electrocatalysts by tuning nanostructure

Chemical-electrical energy conversion and storage are greatly attractive for the development of sustainable energy. Among the chemical-electrical energy conversion devices, polymer electrolyte membrane fuel cell (PEMFC) is one promising technology for portable applications, from as small as portable electronics, to as large as automobiles. One key for PEMFCs is the electrocatalyst. Development of high-performance electrocatalyst nanomaterials relies on tuning material structures at nanoscale. This is in particular manifested in the design of electrocatalysts demanding both high activity and durability. Through solution-phase-synthesis, high quality nanocrystals are prepared at various morphologies (shape-controlled) and compositions (composition-controlled). The nanostructure (i.e. selective exposing specific low-index surface, controlling core-shell structure, and etc.) of nanocrystals are also carefully tuned. Moreover, binary nanocrystal superlattices offer new opportunity to explore electrocatalysis by incorporating physical and chemical properties of different materials in one single, crystalline, and complex nanostructure. Using these highly controlled nanocrystals and nanostructures as research platforms, we explore the correlation between nanostructure and activity (and/or durability). Herein, a group of high performance electrocatalysts are developed for various electrocatalytic processes, including oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER). It is well-demonstrated that the careful manipulation of nanostructure of electrocatalysts is crucial to improve the activity and durability.

Kang, Yijin↗

Quantum dot based memory devices: Current status and future prospect by simulation perspective

We discuss the simulation of floating gate MOSFET memory performance consists of Si/Ge/Si quantum dots for electronics storage nodes with higk-κ material as the tunnel oxide. Heterostructure quantum dot was proposed to maintain the good memory performance without losing the long retention characteristic. As the results, retention time could be increase significantly without deteriorating the writing/erasing speed. By selected the dot size of 9–15nm and the tunnel oxide thickness of 2nm, the retention characteristic can reach up to 10{sup 9}s while the writing and erasing time at the order of 10{sup −6}s. By replace the SiO{sub 2} tunnel oxide with high-κ material such as HfO{sub 2}, ZrO{sub 2}, and Y{sub 2}O{sub 3} the leakage current due to the shrinkage of tunnel oxide thickness can be suppressed by the factor of 10 for the EOT lower than ∼1nm. Moreover, the charge-trapping that generated by the defect at Si substrate and higk-κ material interface are fully considered. We found that, the charge-trapping affects the retention time and memory operation performance. By increasing the charge-trapping depth and width, the memory operation time decrease significantly while the retention characteristic slightly improved.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

Effect of Substrate Temperature on the Electrochemical and Supercapacitance Properties of Pulsed Laser-Deposited Titanium Oxynitride Thin Films

Electrocatalytically active titanium oxynitride (TiNO) thin films were fabricated on commercially available titanium metal plates using a pulsed laser deposition method for energy storage applications. The elemental composition and nature of bonding were analyzed using X-ray photoelectron spectroscopy (XPS) to reveal the reacting species and active sites responsible for the enhanced electrochemical performance of the TiNO electrodes. Symmetric supercapacitor devices were fabricated using two TiNO working electrodes separated by an ion-transporting layer to analyze their real-time performance. The galvanostatic charge–discharge studies on the symmetric cell have indicated that TiNO films deposited on the polycrystalline titanium plates at lower temperatures are superior to TiNO films deposited at higher temperatures in terms of storage characteristics. For example, TiNO films deposited at 300 °C exhibited the highest specific capacity of 69 mF/cm 2 at 0.125 mA/cm 2 with an energy density of 7.5 Wh/cm 2 . The performance of this supercapacitor (300 °C TiNO) device is also found to be ~22% better compared to that of a 500 °C TiNO supercapacitor with a capacitance retention ability of 90% after 1000 cycles. Furthermore, the difference in the electrochemical storage and capacitance properties is attributed to the reduced leaching away of oxygen from the TiNO films by the Ti plate at lower deposition temperatures, leading to higher oxygen content in the TiNO films and, consequently, a high redox activity at the electrode/electrolyte interface.

30 DIRECT ENERGY CONVERSION↗

Preliminary Mark-18A (Mk-18A) Target Material Recovery Program Product Acceptance Criteria

The Mk-18A Target Material Recovery Program (MTMRP) was established in 2015 to preserve the unique materials, e.g. 244 Pu, in 65 previously irradiated Mk-18A targets for future use. This program utilizes existing capabilities at SRS and Savannah River National Laboratory (SRNL) to process targets, recover materials from them, and to package the recovered materials for shipping to ORNL. It also utilizes existing capabilities at ORNL to receive and store the recovered materials, and to provide any additional processing of the recovered materials or residuals required to prepare them for future beneficial use. The MTMRP is presently preparing for the processing of these valuable targets which is expected to begin in ~2019. As part of the preparations for operations, this report documents the preliminary acceptance criteria for the plutonium and heavy curium materials to be recovered from the Mk-18A targets at SRNL for transport and storage at ORNL. These acceptance criteria were developed based on preliminary concepts developed for processing, transporting, and storing the recovered Mk-18A materials. They will need to be refined as these concepts are developed in more detail.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

Chemically Stable Polyarylether-Based Metallophthalocyanine Frameworks with High Carrier Mobilities for Capacitive Energy Storage

Covalent organic frameworks (COFs) with efficient charge transport and exceptional chemical stability are emerging as an import class of semiconducting materials for opto-/electronic devices and energy-related applications. However, the limited synthetic chemistry to access such materials and the lack of mechanistic understanding of carrier mobility greatly hinder their practical applications. Herein, we report the synthesis of three chemically stable polyarylether-based metallophthalocyanine COFs (PAE-PcM, M = Cu, Ni, and Co) and facile in situ growth of their thin films on various substrates (i.e., SiO 2 /Si, ITO, quartz) under solvothermal conditions. We show that PAE-PcM COFs thin films with van der Waals layered structures exhibit p -type semiconducting properties with the intrinsic mobility up to ~19.4 cm 2 V -1 s -1 and 4 orders of magnitude of increase in conductivity for PAE-PcCu film (0.2 S m -1 ) after iodine doping. Density functional theory calculations reveal that the carrier transport in the framework is anisotropic, with the out-of-plane hole transport along columnar stacked phthalocyanine more favorable. Furthermore, PAE-PcCo shows the redox behavior maximumly contributes ~88.5% of its capacitance performance, giving rise to a high surface area normalized capacitance of ~19 μF cm -2 . Overall, this work not only offers fundamental understandings of electronic properties of polyarylether-based 2D COFs but also paves the way for their energy-related applications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

The Effect of Electron Lens as Landau Damping Device on Single Particle Dynamics in HL-LHC

An electron lens can serve as an effective mechanism for suppressing coherent instabilities in high intensity storage rings through nonlinear amplitude dependent betatron tune shift. However, the addition of a strong localized nonlinear focusing element to the accelerator lattice may lead to undesired effects in particle dynamics. We evaluate the effect of a Gaussian electron lens on single particle motion in HL-LHC using numerical tracking simulations, and compare the results to the case when an equal tune spread is generated by conventional octupole magnets.

43 PARTICLE ACCELERATORS↗

EUREICA: Efficient UltRa Endpoint IoT-enabled Coordinated Architecture

The electricity grid has evolved from a physical system to a cyber-physical system with digital devices that perform measurement, control, communication, computation, and actuation. The increased penetration of distributed energy resources (DERs) that include renewable generation, flexible loads, and storage provides extraordinary opportunities for improvements in efficiency and sustainability. However, they can introduce new vulnerabilities in the form of cyberattacks, which can cause significant challenges in ensuring grid resilience. The purpose of this project was to develop a framework ((Efficient, Ultra-REsilient, IoT-Coordinated Assets, or EUREICA)for achieving grid resilience through suitably coordinated assets including a network of Internet of Things (IoT) devices, and a local electricity market (LEM) to identify trustable assets and carry out this coordination. Situational Awareness (SA) of locally available DERs with the ability to inject power or reduce consumption is enabled by the market, together with a monitoring procedure for their trustability and commitment. Experiments conducted during this project demonstrated that, with this SA, a variety of cyberattacks can be mitigated using local trustable resources without stressing the bulk grid. The demonstrations were carried out using a variety of high-fidelity co-simulation platforms, real-time hardware-in-the-loop validation, and a utility-friendly simulator.

14 SOLAR ENERGY↗

Soft error-mitigating semiconductor design system and associated methods

A soft error-mitigating semiconductor design system and associated methods that tailor circuit design steps to mitigate corruption of data in storage elements (e.g., flip flops) due to Single Events Effects (SEEs). Required storage elements are automatically mapped to triplicated redundant nodes controlled by a voting element that enforces majority-voting logic for fault-free output (i.e., Triple Modular Redundancy (TMR)). Storage elements are also optimally positioned for placement in keeping with SEE-tolerant spacing constraints. Additionally, clock delay insertion (employing either a single global clock or clock triplication) in the TMR specification may introduce useful skew that protects against glitch propagation through the designed device. The resultant layout generated from the TMR configuration may relax constraints imposed on register transfer level (RTL) engineers to make rad-hard designs, as automation introduces TMR storage registers, memory element spacing, and clock delay/triplication with minimal designer input.

Miryala, Sandeep↗

Soft error-mitigating semiconductor design system and associated methods

A soft error-mitigating semiconductor design system and associated methods that tailor circuit design steps to mitigate corruption of data in storage elements (e.g., flip flops) due to Single Events Effects (SEEs). Required storage elements are automatically mapped to triplicated redundant nodes controlled by a voting element that enforces majority-voting logic for fault-free output (i.e., Triple Modular Redundancy (TMR)). Storage elements are also optimally positioned for placement in keeping with SEE-tolerant spacing constraints. Additionally, clock delay insertion (employing either a single global clock or clock triplication) in the TMR specification may introduce useful skew that protects against glitch propagation through the designed device. The resultant layout generated from the TMR configuration may relax constraints imposed on register transfer level (RTL) engineers to make rad-hard designs, as automation introduces TMR storage registers, memory element spacing, and clock delay/triplication with minimal designer input.

Miryala, Sandeep↗

Shorting at Long Duration: Impact of Extended Discharge Capacity on Battery Solid Electrolytes

Long-duration energy storage (LDES) is critical to a stable, resilient, and decarbonized electric grid. While batteries are emerging as important LDES devices, extended, high-power discharges necessary for cost-competitive LDES present new materials challenges. Here, focusing on a new generation of low-temperature molten sodium batteries, we explore here unique phenomena related to long-duration discharge through a well-known solid electrolyte, NaSICON. Specifically, molten sodium symmetric cells at 110°C were cycled at 0.1 A cm -2 for 1-23 h discharges. Longer discharges led to unstable overpotentials, reduced resistances, and decreased electrolyte strength, caused by massive sodium penetration not observed in shorter duration discharges. Scanning electron microscopy informed mechanisms of sodium penetration and even “healing” during shorter-duration cycling. Importantly, these findings show that traditional, low-capacity, shorter-duration tests may not sufficiently inform fundamental materials phenomena that will impact LDES battery performance. This case highlights the importance that candidate LDES batteries be tested under pertinent long-duration conditions.

25 ENERGY STORAGE↗

High energy storage capacitor by embedding tunneling nano-structures

In an All-Electron Battery (AEB), inclusions embedded in an active region between two electrodes of a capacitor provide enhanced energy storage. Electrons can tunnel to/from and/or between the inclusions, thereby increasing the charge storage density relative to a conventional capacitor. One or more barrier layers is present in an AEB to block DC current flow through the device. The AEB effect can be enhanced by using multi-layer active regions having inclusion layers with the inclusions separated by spacer layers that don't have the inclusions. The use of cylindrical geometry or wrap around electrodes and/or barrier layers in a planar geometry can enhance the basic AEB effect. Other physical effects that can be employed in connection with the AEB effect are excited state energy storage, and formation of a Bose-Einstein condensate (BEC).

25 ENERGY STORAGE↗

Comparison of AC Losses of YBCO Circular Pancake Coils and Infinitely Long Stack Approximation

High-temperature superconducting (HTS) coils are key parts of many large-scale AC applications, such as transformers, superconducting magnetic energy storage, and motors. The estimation of AC losses of pancake coils is necessary for optimizing the design of HTS devices and cryogenic systems. To speed up the computation of AC losses, the numerical model of an infinitely long HTS stack is often utilized. An HTS stack is a good approximation of the circular coil only if the coil radius is sufficiently large, since AC losses will exhibit a stronger asymmetry along the radial direction for small values of coil radii. To assess the validation of an infinitely long stack approximation, the comparisons of AC losses between infinitely long stacks and circular coils with different radii are presented. The turn number varies from 10 to 80. We find that the AC losses of HTS circular coils will gradually increase to the same value as an infinitely long stack with increasing coil radii. A new parameter is proposed to quantitatively describe the correctness of infinitely long stack approximation. Finally, a method of AC loss estimation of HTS pancake coils is proposed.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗