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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 721 records · Page 40
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Experimental characterization and analysis of phase change material-based thermal energy storage system for refrigerated display case

Refrigerated display cases that are used to store and exhibit food products in supermarkets and retail spaces consume a significant portion of the buildings’ total electricity. Importantly, the refrigeration-related energy cost and demand charges are greatly affected by the time-of-use electricity pricing and demand rates, which are at their maximum during peak hours, typically when refrigeration energy consumption is also high. Using energy storage to shift the refrigeration load from peak to off-peak hours can greatly reduce the operational costs in the supermarket. This study demonstrates a phase change material-based thermal energy storage (TES) system, specifically designed in stackable units, that can be integrated with an open vertical refrigerated display case. We perform numerical and experimental characterization that includes finite-difference modeling for the TES, prototype fabrication, and laboratory evaluation, followed by a preliminary system-level analysis to predict the impact of TES on the refrigerated case performance, energy use, and energy cost. The results show that the dedicated latent TES for refrigerated cases can provide a specific energy of 50.4 Wh/kg and a specific power of 15.5 W/kg. The TES can be charged during 12 h of the off-peak period and discharged at various rates during 4 to 6 h of the peak period, thereby shifting the refrigeration load from the peak to the off-peak period. Consequently, annual cost savings up to 19% can be achieved, depending on the thermal load, the summer/winter peak electricity pricing, and the transition temperature of the phase change material used.

25 ENERGY STORAGE↗
DOE OSTI2023

Fabrication, Modeling, and Testing of a Prototype for Particle Thermal Energy Storage Containment

Increasing penetration of variable renewable energy resources requires the deployment of energy storage at a range of durations. Long-duration energy storage (LDES) technologies will fulfill the need to firm variable renewable energy resource output throughout the year. Conventional electrochemical batteries (e.g., lithium-ion) are uneconomical in this role due to high energy capacity costs. Thermal energy storage (TES) is one promising technology for LDES applications because of its siting flexibility and ease of scaling. Particle-based TES systems use low-cost solid particles that have higher temperature limits than the molten salts used in traditional concentrated solar power systems. A key component in particle-based TES systems is the containment silo for the high-temperature (> 1100 degrees C) particles. This study combined experimental testing and computational modeling methods to design and characterize the performance of a particle containment silo for LDES applications. A containment silo prototype was built at a laboratory scale and used to validate a congruent transient finite element analysis (FEA) model. The validation compared the actual and predicted temperature profile through the prototype over six days as the particles cooled from their initial temperature. The performance of a commercial scale (> 5 GWhth) was then characterized using the validated model. The transient FEA model was subject to several charge-discharge cycles to mimic a possible operating schedule. The commercial-scale model predicted a storage efficiency in excess of 95% after five days of storage with a design storage temperature of 1200 degrees C. Insulation material and concrete temperature limits were considered as well. The validation of the methodology means the FEA model can simulate a range of scenarios for future applications. This work supports the development of a promising LDES technology with implications for grid-scale electrical energy storage, but also for thermal energy storage for industrial process heating applications.

ENERGY STORAGE↗
DOE OSTI2021

Maximizing Solar and Transportation Synergies

This report considers the technological and market pathways that will enable better use of photovoltaic (PV) electricity as fuel for future transportation demand. Most of the pathways identified will require collaborative research and development (R&D) efforts to improve the capabilities of multiple technologies, including PV, energy storage, vehicles, electrolyzers, electrofuels, and infrastructure. For plug-in electric vehicles (PEVs), technologies that enable wide-scale managed and coordinated charging are among the highest priorities for continued research, development, and deployment in the near term. Furthermore, managed and coordinated charging capabilities are foundational for future vehicle-to-grid (V2G) functionality in the long term. For hydrogen fuel cell electric vehicles (FCEVs), the use of PV electricity for electrolysis provides an opportunity to increase PV deployment. For rail, air, and maritime transportation, the feasibility of increased PV use varies in the near term; opportunities for synergies with solar include the electrification of rail, increased reliability from airport microgrids, and switching from heavy fuel oil to clean maritime electrofuels made from PV-based hydrogen. Over the longer term, battery swap stations for electric airplanes and the co-location of solar with hydrogen fueling stations at shipping ports may enable greater synergies between PV and transportation.

14 SOLAR ENERGY↗
DOE OSTI2024

System and Component Development of Particle-Based Pumped Thermal Energy Storage

Reliable power supply from variable renewable resources requires energy storage at various scales to overcome resource intermittency. Long-duration energy storage (LDES, 10-100 hours) can improve dispatchability and grid reliability with increasing levels of renewable power supply. Thermal energy storage (TES) has siting flexibility and the ability to store a large capacity of energy, and thus has the potential to meet the LDES need and provide charging and discharging durations beyond the economic capacity of conventional batteries. TES technology has evolved from concentrating solar thermal power (CSP) generation and is recognized as an economic large-scale energy storage method. A standalone electric-thermal energy storage system supporting renewable integration of wind and solar power without CSP solar field can firm renewable generation and boost overall grid resilience and security.

concentrating solar thermal power↗
DOE OSTI2024

Unlocking High Capacity and Reversible Alkaline Iron Redox Using Silicate-Sodium Hydroxide Hybrid Electrolytes

Alkaline iron (Fe) batteries are attractive due to the high abundance, low cost, and multiple valent states of Fe but show limited columbic efficiency and storage capacity when forming electrochemically inert Fe 3 O 4 on discharging and parasitic H 2 on charging. Herein, sodium silicate is found to promote Fe(OH) 2 /FeOOH against Fe(OH) 2 /Fe 3 O 4 conversions. Electrochemical experiments, operando X-ray characterization, and atomistic simulations reveal that improved Fe(OH) 2 /FeOOH conversion originates from (i) strong interaction between sodium silicate and iron oxide and (ii) silicate-induced strengthening of hydrogen-bond networks in electrolytes that inhibits water transport. Furthermore, the silicate additive suppresses hydrogen evolution by impairing energetics of water dissociation and hydroxyl de-sorption on iron surfaces. In conclusion, this new silicate-assisted redox chemistry mitigates H 2 and Fe 3 O 4 formation, improving storage capacity (199 mAh g -1 in half-cells) and coulombic efficiency (94 % after 400 full-cell cycles), paving a path to realizing green battery systems built from earth-abundant materials.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Revealing the Fast and Durable Na + Insertion Reactions in a Layered Na 3 Fe 3 (PO 4 ) 4 Anode for Aqueous Na-Ion Batteries

Aqueous sodium-ion batteries represent a promising approach for stationary energy storage; however, the lack of appropriate anode materials has substantially retarded their development. Herein, we demonstrated an iron-based phosphate material of Na 3 Fe 3 (PO 4 ) 4 as an inexpensive and efficacious anode alternative. While the Fe 3+ /Fe 2+ redox couple renders a two-Na-insertion reaction with desirable potentials, its unique layered structure further facilitates the Na-insertion kinetics and reversibility. Consequently, this electrode exhibits an appealing Na-insertion performance, with a reversible capacity of ~83 mAh g –1 , suitable anode potential of -0.4 V vs Ag/AgCl, excellent rate capability of 200 C, and outstanding cycling of 6000 cycles. Utilizing operando synchrotron X-ray diffraction and X-ray absorption spectroscopy, we revealed the structural evolution of the Na 3 Fe 3 (PO 4 ) 4 anode during the two-electron reaction, where the extremely small volume expansion (~3%) enables its fast-charging and long-cycling capability. Our work suggests new considerations of developing versatile iron phosphate compounds as appealing anode materials for energy storage in aqueous electrolytes.

25 ENERGY STORAGE↗
DOE OSTI2022

Optimizing Price-Informed Operation of a Battery Storage System in an Office Building

New prescriptive efficiency requirements amended to US model energy codes historically have been evaluated using an average, blended electricity rate, which obscures demand charges. Post 2019, new measures can be evaluated using a representative time-of-use (TOU) tariff yet more sophisticated analysis methods are needed to consider a variety of TOU tariffs and assess price-informed control. To address these needs, this study couples building prototype simulation model with varying-in-sophistication battery storage operating strategies for different electricity TOU tariffs. The analysis compares the impact of operating a battery storage system following simpler rule-of-thumb methods versus a semi-optimized priced-informed heuristic approach. The investigation demonstrates that the heuristic approach results in greater electricity cost savings and is practical to implement.

Lei, Xuechen↗
DOE OSTI2024

Recommended Actions to Improve Adapter Safety

With the rapid advancement and acceleration in the electric vehicle (EV) industry within the United States, major automakers and EV charging companies are increasingly adopting the North American Charging Standard (NACS) connector style, now officially known as J3400. This shift is expected to enhance charging infrastructure, providing a better customer experience by making it easier for all EV drivers to access a wider network of direct-current (DC) fast chargers (DCFCs). However, the adoption of the J3400 standard presents challenges for many EVs already on the roads and some currently coming off production lines that are equipped with the Combined Charging System (CCS) connector, which this report will refer to as the North American standard, CCS1. These vehicles will need adapters to use new or existing J3400 infrastructure. During this transition, several issues have emerged. Firstly, there is a need to standardize the new connector type to ensure it is interoperable, safe, and reliable. Second, existing CCS EV drivers need a way to access the J3400 network, which will require electric vehicle supply equipment (EVSE) or sites with both connector types, driver-provided adapters to physically convert from CCS to J3400, or EVSE with retained adapters designed for use with the EVSE. Third, adapter standards will need to be written to specify how they will be designed and what evaluations will be needed to ensure safe and reliable performance. To address these challenges, adapters that support different types of charging connectors will be essential. These adapters will play a crucial role in supporting the transition and ensuring continued service for legacy EVs with CCS inlets as the J3400 standard becomes the predominant one in the United States. Consequently, the National Charging Experience (ChargeX) Consortium has investigated and performed a teardown analysis on the different adapter versions on the market. The aim is to create a failure mode and effects analysis (FMEA) on what are expected to be the most common adapter types used in this transition. In order to support this work, we executed an FMEA exercise with the main goal of identifying gaps in the existing adapters' performance and conformance to the most common safety requirements of high-power and high-voltage devices. This effort focused on adapters provided by the driver, as these may present the highest safety and reliability risks. The recommendations made here apply to both retained and driver-provided adapters.

25 ENERGY STORAGE↗
DOE OSTI2020

Cell degradation quantification—a performance metric-based approach

A safe and reliable battery operation needs effective diagnostic tools. A quantitative failure analysis (FA) to enable cell qualification and quantify its effectiveness for reliable and safe operation of rechargeable Li batteries (RLB) is shown here. The method can identify and quantify potential failure based on the state of charge (SOC) under any operating conditions. A precise and accurate electrochemical analytic diagnosis (eCAD) of 14 rechargeable Li || NMC622 cells of the same build are used as an example. The FA by eCAD can quantitatively decipher good, bad and ugly cells in cycle aging. The cell qualification is based on thermodynamic SOC, not experimental conditions. The method provides a quantitative failure mode and effect analysis (FMEA) to reveal diverse “dead Li” formation that affects the reversibility of the Li anode and charge retention in the cell. This cell qualification method highlights the potential to improve cell quality for safe operation, with strong implications for early fault detection, FA, risk mitigation, state estimation and life prediction for reliable and safe RLB operations

25 ENERGY STORAGE↗
DOE OSTI2022

Enhanced Electrolyte Transport and Kinetics Mitigate Graphite Exfoliation and Li Plating in Fast–Charging Li–Ion Batteries

Despite significant progress in energy retention, lithium-ion batteries (LIBs) face untenable reductions in cycle life under extreme fast-charging (XFC) conditions, which primarily originate from a variety of kinetic limitations between the graphite anode and the electrolyte. Through quantitative Li + loss accounting and comprehensive materials analyses, it is directly observed that the operation of LIB pouch cells at 4 C||C/3 (charging||discharging) results in Li plating, disadvantageous solid-electrolyte-interphase formation, and solvent co-intercalation leading to interstitial decomposition within graphite layers. It is found that these failure modes originate from the insufficient properties of conventional electrolytes, where employing a designed ester-based electrolyte improved the capacity retention of these cells from 55.9% to 88.2% after 500 cycles when operated at the aforementioned conditions. These metrics are the result of effective mitigation of the aforementioned failure modes due to superior Li + transport and desolvation characteristics demonstrated through both experimental and computational characterization. Finally, this work reveals the vital nature of electrolyte design to XFC performance.

25 ENERGY STORAGE↗
DOE OSTI2023

Stable Cycling with Intimate Contacts Enabled by Crystallinity–Controlled PTFE–Based Solvent–Free Cathodes in All–Solid–State Batteries

All-solid-state batteries (ASSBs) employing Li-metal anodes and inorganic solid electrolytes are attracting great attention due to high safety and energy density for next-generation energy storage devices. However, the volume change of cathode active materials can cause contact loss, resulting in charge carrier isolation, heterogeneous current distribution, and poor electrochemical properties in ASSBs. Here, a simple, yet effective, solvent-free electrode engineering approach with polytetrafluoroethylene (PTFE) as a binder for ASSBs is reported, enabling intimate contact and stable interfaces with the cathode. It is substantiated that the crystallinity of PTFE can be controlled depending on the heat history, and highly crystalline PTFE displays robust mechanical properties. High-nickel LiNi 0.8 Mn 0.1 Co 0.1 O 2 cathode prepared with crystalline PTFE show improved cycle and rate performances in ASSBs. In addition, it is revealed that the intimate contact between cathode particles with a stable cathode electrolyte layer is maintained during cycling by postmortem studies. Furthermore, this simple engineering method can be applied to prepare cathodes with a variety of active materials and solid electrolytes in ASSBs.

25 ENERGY STORAGE↗
DOE OSTI2022

Laser ablation for structuring Li-ion electrodes for fast charging and its impact on material properties, rate capability, Li plating, and wetting

Laser ablation is a scalable technique for decreasing the effective tortuosity of electrodes by selectively removing material with high precision. Applied to ≈ 110 um thick electrode coatings, this work focuses on understanding the impact of laser ablation on electrode material properties at the beginning of life and synergistic impacts of ablated channels on cell performance throughout their cycle life. Post laser ablation, local changes in chemistry, crystallography, and morphology of the laser-impacted electrode regions are investigated. It is shown that femtosecond pulsed laser ablation can achieve high-rate material removal with minor material damage locally at the interface of the impacted zones. The capacity achieved during a 6C (10 min) constant-current constant-voltage charge to 4.2 V improved from 1 mAh cm -2 for the non-ablated electrodes to almost 2 mAh cm -2 for the ablated electrodes. This benefit is attributed to a synergistic effect of enhanced wetting and decreased electrode tortuosity. The benefit was maintained for over 120 cycles, and upon disassembly decreased Li-plating on the graphite anode was observed. Finally, multi-physics modeling in conjunction with wetting analyses showed that laser ablating either one of the electrodes led to substantial improvements in wetting and rate capability, indicating that substantial performance benefits can be achieved by ablating only the graphite anode as apposed to both electrodes.

25 ENERGY STORAGE↗
DOE OSTI2024

Topology Optimization for Full-Cell Electrochemical Energy Storage Device

This code is used to conduct topology optimization of a general full cell energy storage device. The anode and cathode designs are optimized simultaneously, allowing possibility for interdigitation. The charging mechanism can consist of both electric double layer charging (EDLC) typically observed in capacitors and redox reaction typically observed in batteries.

Roy, Thomas↗
DOE OSTI2023

Electrically Driven Ion Separations in Permeable Membranes

Ion separations are critical for producing materials such as Li and rare-earth element salts that are essential for applications including energy storage and production. This research aimed to develop and understand separations of singly and multiply charged ions as well as separations among different singly charged ions such as Li + and Na + . Thin layers of polyelectrolytes on membranes allow passage of singly charged ions at rates 1000 times faster than those for multiply charged ions. This allows purification of mixtures with equal concentrations of Li + and Mg 2+ to create a permeate solution with >99% Li + . Such membranes may also effectively isolate rare earth elements. To separate Li + and K + , this work developed opposing flow and current in membranes. The current overcomes the flow of K + to allow Li + to selectively pass through the membrane, leading to Li + /K + selectivities around 70. All of the research employs modelling to better understand the mechanism of these separations, which includes transport driven by gradients in electrical potential, concentration, and pressure. The interplay of these driving forces can create highly selective separations.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Chemo-Mechanically Driven In Situ Hierarchical Structure Formation in Mixed Conductors (Final Technical Report)

This document is the Final Technical Report for the Early Career project DE-SC0018963. Essential materials for energy technologies tend to exhibit “hierarchical” functions – they perform multiple, inter-related tasks at different locations, across disparate length and time scales. To best support this heterogeneous function, there is a fundamental need to understand and direct formation of corresponding tailored hierarchical architectures. In particular, a wide variety of applications, from energy conversion and storage to sensing and gas separation, rely on oxide mixed ionic and electronic conductors (MIECs). These critical ceramic materials catalyze reactions at their surfaces and selectively transport both ionic and electronic species in the bulk. Ideally, MIECs should adopt hierarchical structures with 1) high surface areas, 2) surface compositions exhibiting high catalytic activity, and 3) microstructural connectivity in the direction needed for fast mass and charge transport. In practice, however, MIECs.

08 HYDROGEN↗
DOE OSTI2023

Thermal energy storage in concrete utilizing a thermosiphon heat exchanger

The performance of a lab-scale concrete thermal energy storage (TES) module with a 2-kWh thermal capacity is evaluated at temperatures up to 400 °C. The TES module uses conventional normal weight concrete with thermal and mechanical properties that are tailored for use as a solid thermal energy storage media. A thermosiphon heat exchanger is used to provide rapid heat transfer into the concrete module, which is reinforced with a steel pipe outer shell. The charging and discharging cycles are examined to assess the thermal performance of the concrete and thermosiphon. Based on the results of testing, the thermosiphon is able to repeatably charge the concrete module from 300 to 400 °C over a 4-h period. After 2250 total hours of charge and discharge cycles, there was no observed delamination between the concrete and the thermosiphon or the steel jacket reinforcement. Non-destructive measurements of the concrete indicated no significant degradation of the solid storage media. The experimental results are then used to validate a numerical model of the concrete TES module for parametric study. Finally, varying insulation conditions were analyzed using this model to determine practical configurations for regular operation of the proposed concrete TES module.

25 ENERGY STORAGE↗
DOE OSTI2023

Dynamic In‐Plane Heterogeneous and Inverted Response of Graphite to Fast Charging and Discharging Conditions in Lithium‐Ion Pouch Cells

Solutions for improving fast charging of lithium‐ion batteries have largely focused on alleviating through‐plane lithiation gradients while little is understood about in‐plane heterogeneities and how to resolve them. Herein, high‐speed synchrotron X‐ray diffraction (XRD) resolves graphite lithiation spatially and temporally during 6 C charging and 2 C discharging. At every point during operation, considerable differences in the state of lithiation across the pouch cell are present. Some regions are more responsive to operation than others, reaching full lithiation early during charge and full delithiation during discharge. Other regions within the cell never fully delithiate during discharge, despite a prolonged voltage hold at 2.8 V. Using time‐resolved XRD data, the calculated local current density (mA cm −2 ) at the graphite surface shows an unexpected occurrence of local inverted current densities where regions of graphite are observed to delithiate during charging and lithiate during discharging. A pseudo‐3D model is developed for the graphite electrode with spatially varying microstructural tortuosity to show how microstructural heterogeneity could influence spatial charge dynamics. The model could not predict the complex in‐plane charge behavior observed within the cell. Consequently physics‐based charging protocols based on homogeneous electrode assumptions may underestimate the local variations in charge dynamics and occurrence of lithium plating.

25 ENERGY STORAGE↗
DOE OSTI2025

Models and Measurements Quantify Photon Recycling, Charge-Carrier Diffusion and Photon Scattering Contributions to Photoluminescence in InP Nanowire Arrays

Nanowire arrays present many unique advantages for solar-to-chemical energy conversion. One possible advantage is that photon recycling between neighboring nanowires has the potential to increase solar energy conversion efficiencies. Here, in this work, we explore three underlying mechanisms of optical and electronic coupling between neighboring nanowires─incident photon scattering, photon recycling, and charge-carrier transport from the photoexcited nanowire to the neighboring nanowire via the underlying substrate─using single nanowire-level microscopy and spectroscopy measurements. We present a comprehensive analysis of light absorption and emission of a single nanowire at open circuit, and subsequent re-absorption and re-emission by a neighboring nanowire. We developed a novel correlated single nanowire microspectroscopy and widefield imaging methodology to spatially resolve photon communication pathways between neighboring nanowires and selectively image re-emitted and reflected photons. We developed unique multiphysics models to couple wave optics and semiconductor photophysics to especially isolate contributions from photon recycling and electronic transport to photon emission from neighboring nanowires. By systematically varying the morphologies of the nanowires modeled, we identified pathways to maximize photon recycling between neighboring nanowires. We concluded that the measured photoluminescence is more strongly influenced by the diffusion of charge carriers as compared to photon recycling in materials with moderate-to-large charge-carrier mobilities (>10 cm 2 V –1 s –1 ), and that photon recycling dictates photoluminescence intensity only when the charge-carrier mobility is low (<1 cm 2 V –1 s –1 ). The experimental and simulation platforms developed herein for photon management strategies can be leveraged by the semiconductor photocatalysis community to enhance solar-to-chemical conversion efficiencies in semiconductor nanowire arrays.

25 ENERGY STORAGE↗