Results for “capacity loss” — Page 52

NASA NTRS2026

High Temperature Dielectric Properties and Differential Scanning Calorimetry of Lunar Simulants

To guide development of microwave process technology that could be used during in situ construction on the Moon, we measured the high-temperature basic dielectric properties (εʹ and εʺ) of 17 lunar simulants and related materials. In order to confidently use these data one needs to understand the data’s strengths and weaknesses. Therefore, a goal of this publication is to provide insights into the comparative effects of sample composition, pre-treatments, experimental variables, high temperatures, and other factors on the measured response. The dielectric measurements were performed using the cavity perturbation method over a temperature range between room temperature to 1000 °C, or higher, and provided the real and imaginary components of permittivity at six frequencies. The utility of the original values was limited by the varying density of the pellets used in the measurement. Therefore, all of the εʹ and εʺ measurements at the frequency of 2466 MHz have been scaled to a constant density, 1.75 g/cm 3 . Here the data are presented as graphs chosen to aid analysis within and across simulant groups. To gain additional insight into the processes happening at the elevated temperatures in the dielectric measurements, heat capacity data was obtained using differential scanning calorimetry (DSC) on several of the simulant materials. Our data show that over the frequency range 397 MHz – 2985 MHz a material’s behavior does not greatly change, as compared to the scale of differences observed between lunar mare and highland simulants at high temperatures. For example at 1000 °C, the mare simulant JSC-1A absorbs 10 times more power than the highland simulant NUW-LHT-5M. We observe that as melting temperatures are reached both permittivity and dielectric loss rise non-linearly, helping to explain thermal runaway during microware heating. Our data show that even less than a few weight % of many non-lunar minerals, and the use of mixtures in simulants can affect the dielectric behavior at higher temperatures. A comparison of our results with published dielectric data for Apollo samples and with remote sensing of the Moon supports the conclusion the simulants and lunar material at room temperature have very similar dielectric values.

Differential Scanning Calorimetry↗

DOE OSTI2021

Reactivity with Water and Bulk Ruthenium Redox of Lithium Ruthenate in Basic Solutions

Explore the source record for details and available documents.

Rao, Reshma R.↗

DOE OSTI2025

Anion exchange membrane test protocol validation

This study presents the validation of protocols for measuring ion exchange capacity (IEC) and alkaline stability of anion exchange membranes (AEMs) for low-temperature water electrolysis. While protocols are often tested within individual laboratories, their results across multiple laboratories with varying equipment, environmental conditions, and personnel qualification remain unverified. The validation involved Los Alamos National Laboratory (LANL), National Renewable Energy Laboratory (NREL), and University of Oregon (UO) using the same commercially available AEM to assess reproducibility and reliability of the protocols under diverse conditions. For the IEC protocol, results across laboratories were consistent within ±10% of the NMR-determined reference value. The alkaline stability protocol could pose greater challenges due to factors such as variations in sample collection timing, preservation methods, and analytical techniques, but consistent test results for percentage IEC loss were demonstrated across institutions. These results highlight the reliability and applicability of the protocols, emphasizing the importance of validation to ensure consistency in diverse research environments.

08 HYDROGEN↗

DOE OSTI2020

Unraveling Na and F coupling effects in stabilizing Li, Mn-rich layered oxide cathodes via local ordering modification

Regardless of the prevailing capacity and energy density of lithium, manganese-rich layered oxide (LMR-NMC) cathodes, continuous decay of voltage and overall energy density during cycling hinders this material from commercialization in Li-ion batteries. Although significant work focuses on single doping of Na and F, analysis in portraying the benefit of these ions in diminishing the structural distortion during activation cycle is in doubt. In this study, the effects of co-doping Na and F into the LMR-NMC structure in stabilizing the structure and mitigating oxygen loss during the first cycle are closely examined via in situ x-ray measurements. Na and F co-doping shows a 30% lower degree of Li + /Ni 2+ mixing in the Li layer (C2/m structure), 50% reduced Debye-Waller factor of Mn-O bonding, increase reversible TM migration, and faster Li diffusion relative to the pristine material. Due to the utilization of Ni redox chemistry below 4.4 V, less oxygen redox is required for charge compensation at high voltage. This study offers the first instance to quantitatively evaluate the effects of co-doping Na and F in LMR-NMC cathode in order to minimize voltage degradation by altering the local ordering of O3-type structure, which may rationalize strategies to overcome the issues of the material.

25 ENERGY STORAGE↗

DOE OSTI2024

Genetic and Functional Diversity Help Explain Pathogenic, Weakly Pathogenic, and Commensal Lifestyles in the Genus Xanthomonas

The genus Xanthomonas has been primarily studied for pathogenic interactions with plants. However, besides host and tissue-specific pathogenic strains, this genus also comprises nonpathogenic strains isolated from a broad range of hosts, sometimes in association with pathogenic strains, and other environments, including rainwater. Based on their incapacity or limited capacity to cause symptoms on the host of isolation, nonpathogenic xanthomonads can be further characterized as commensal and weakly pathogenic. This study aimed to understand the diversity and evolution of nonpathogenic xanthomonads compared to their pathogenic counterparts based on their cooccurrence and phylogenetic relationship and to identify genomic traits that form the basis of a life history framework that groups xanthomonads by ecological strategies. We sequenced genomes of 83 strains spanning the genus phylogeny and identified eight novel species, indicating unexplored diversity. While some nonpathogenic species have experienced a recent loss of a type III secretion system, specifically the hrp2 cluster, we observed an apparent lack of association of the hrp2 cluster with lifestyles of diverse species. We performed association analysis on a large data set of 337 Xanthomonas strains to explain how xanthomonads may have established association with the plants across the continuum of lifestyles from commensals to weak pathogens to pathogens. Presence of distinct transcriptional regulators, distinct nutrient utilization and assimilation genes, transcriptional regulators, and chemotaxis genes may explain lifestyle-specific adaptations of xanthomonads.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2023

Dynamic subcanopy leaf traits drive resistance of net primary production across a disturbance severity gradient

Across the globe, the forest carbon sink is increasingly vulnerable to an expanding array of low- to moderate-severity disturbances. However, some forest ecosystems exhibit functional resistance (i.e., the capacity of ecosystems to continue functioning as usual) following disturbances such as extreme weather events and insect or fungal pathogen outbreaks. Unlike severe disturbances (e.g., stand-replacing wildfires), moderate severity disturbances do not always result in near-term declines in forest production because of the potential for compensatory growth, including enhanced subcanopy production. Community-wide shifts in subcanopy plant functional traits, prompted by disturbance-driven environmental change, may play a key mechanistic role in resisting declines in net primary production (NPP) up to thresholds of canopy loss. However, the temporal dynamics of these shifts, as well as the upper limits of disturbance for which subcanopy production can compensate, remain poorly characterized. In this study, we leverage a 4-year dataset from an experimental forest disturbance in northern Michigan to assess subcanopy community trait shifts as well as their utility in predicting ecosystem NPP resistance across a wide range of implemented disturbance severities. Through mechanical girdling of stems, we achieved a gradient of severity from 0% (i.e., control) to 45, 65, and 85% targeted gross canopy defoliation, replicated across four landscape ecosystems broadly representative of the Upper Great Lakes ecoregion. We found that three of four examined subcanopy community weighted mean (CWM) traits including leaf photosynthetic rate (p = 0.04), stomatal conductance (p = 0.07), and the red edge normalized difference vegetation index (p < 0.0001) shifted rapidly following disturbance but before widespread changes in subcanopy light environment triggered by canopy tree mortality. Surprisingly, stimulated subcanopy production fully compensated for upper canopy losses across our gradient of experimental severities, achieving complete resistance (i.e., no significant interannual differences from control) of whole ecosystem NPP even in the 85% disturbance treatment. Additionally, we identified a probable mechanistic switch from nutrient-driven to light-driven trait shifts as disturbance progressed. Our findings suggest that remotely sensed traits such as the red edge normalized difference vegetation index (reNDVI) could be particularly sensitive and robust predictors of production response to disturbance, even across compositionally diverse forests. The potential of leaf spectral indices to predict post-disturbance functional resistance is promising given the capabilities of airborne to satellite remote sensing. We conclude that dynamic functional trait shifts following disturbance can be used to predict production response across a wide range of disturbance severities.

resistance↗

NASA NTRS1980

Tolerance of Lower Body Negative Pressure (LBNP) in endurance runners, weightlifters, swimmers and nonathletes

Thirteen endurance runners (R), 12 weightlifters (WL), 12 swimmers (SW) and 10 nonathletes (NA) were tested for their tolerance of lower body negative pressure (LBNP) in consecutive 5 minute stages at -20, -30, -40, -50 and -60 torr. Each subject also performed an exercise test on a bicycle ergometer with progressive workloads to exhaustion to determined aerobic capacity. The R had a much higher aerobic capacity than any of the other groups, but a significantly lower LBNP tolerance. While responses in heart rate and pulse pressure were quite similar in all 4 groups, the rate of increase in leg volume relative to LBNP stress (leg compliance, LC) was considerably greater in R than in the other athletes and NA. The greater LC in R could be attributed not only to a more rapid shift of blood to the lower extremities but also to a greater tendency for edema formation, both contributing to a more rapid loss in effective central blood volume for a given LBNP stress. These results substantiate earlier observations which led to the conclusion that endurance running is not advisable as a training regimen for astronauts.

Source record↗

NASA NTRS1998

Elemental Fractionation During Rapid Accretion of the Moon Triggered by a Giant Impact

Recently, Ida et al. made an N-body simulation of lunar accretion from a protolunar disk formed by a giant impact. One of their important conclusions is that the accretion time of the Moon is as short as one month. Such rapid accretion is a necessary consequence of the high surface density of a lunar mass disk accreting just beyond the Roche limit (about 3Re); the Safronov accretion time (a few days) is even shorter. The energy of accretion always exceeds the gravitational binding energy of newly arriving matter. Hence, without an energy sink, the accreting body is thermally unstable. For the Earth and other planets, radiation acts as the sink. However, in such a short accretion time, the Moon cannot radiate the accretional energy. Even radiating at a silicate cloudtop temperature of roughly 2000 K, it would take more than 100 yr to radiatively cool the Moon. The plausible alternative heat sinks are heat capacity, latent heat of vaporization, and thermal escape of the gas to space (i.e., hydrodynamic blowoff). The latter becomes plausible for the Moon because the scale height at 2000 K (about 300 km) is a significant fraction of the lunar radius. The early stages of lunar (or "lunatesimal") growth release relatively little energy and can occur simply by heating the material, especially if the accreting material is originally cold. However, the material is unlikely to be cold, because the disk itself is hot and cooling time is long, while the lunar accretion time iss very short. Therefore, the moon is likely to accrete condensed material just after it condenses. Accordingly, the newly accreted material will be on the verge of vaporization and will have very little heat capacity to spare. The immediate heat sink is the latent heat of vaporization. Most of the vapor will escape from the moon, because the thermal energy in the gas can be used to drive escape. However, vaporization is generally incomplete. the latent heat of vaporization exceeds the energy of accretion. Viewed globally, the accretional energy is about half the energy required to vaporize the entire Moon. Thus to first approximation, half of the Moon-forming material can be vaporized and lost during accretion. During this process, we would expect preferential loss of relatively volatile elements. Escape will retard the rate of accretion. To test these ideas, we computed detailed models of the thermal state of the Moon during accretion. We pay special attention to the structure of the silicate atmosphere and its loss rate by calculating the chemical species at equilibrium. We used the PHEQ program which includes 12 elements (H,O,C,Mg,Si,Fe,Ca, Al, Na,Ti, and N.) and 272 compounds (including ionic compounds). Because of the large heats of vaporization and ionization, the adiabatic atmosphere is nearly isothermal and massive escape is expected. The pressure of the atmosphere is determined by the balance between vaporization of a accreting material and escape. If the accretion time is one month, a 0.3 bar atmosphere is expected. Elemental fractionation depends strongly on the temperature of the accreting material. The initial temperature of the material can be estimated from the condition of gravitational instability in the protolunar disk. As shown by Ida et al, accretion starts when gravitational instability occurs when more than 99% of the material condenses. At this point, all of Ca, Al, Si, Mg, and Fe, and 95% of Na (probably K also), are in condensed phases. If the moon is formed from the accretion of such material, volatile elements such as Na, and K are retained by the moon only early in accretion. At later times, K and Na are lost and a fraction of the MG, Si and Fe is lost. However, refractory elements such as Ca and Al are retained and so achieve a mild degree (factor 2) of superabundance.

Abe, Y.↗

NASA NTRS2014

High Efficiency Centrifugal Compressor for Rotorcraft Applications

The report "High Efficiency Centrifugal Compressor for Rotorcraft Applications" documents the work conducted at UTRC under the NRA Contract NNC08CB03C, with cost share 2/3 NASA, and 1/3 UTRC, that has been extended to 4.5 years. The purpose of this effort was to identify key technical barriers to advancing the state-of-the-art of small centrifugal compressor stages; to delineate the measurements required to provide insight into the flow physics of the technical barriers; to design, fabricate, install, and test a state-of-the-art research compressor that is representative of the rear stage of an axial-centrifugal aero-engine; and to acquire detailed aerodynamic performance and research quality data to clarify flow physics and to establish detailed data sets for future application. The design activity centered on meeting the goal set outlined in the NASA solicitation-the design target was to increase efficiency at higher work factor, while also reducing the maximum diameter of the stage. To fit within the existing Small Engine Components Test Facility at NASA Glenn Research Center (GRC) and to facilitate component re-use, certain key design parameters were fixed by UTRC, including impeller tip diameter, impeller rotational speed, and impeller inlet hub and shroud radii. This report describes the design effort of the High Efficiency Centrifugal Compressor stage (HECC) and delineation of measurements, fabrication of the compressor, and the initial tests that were performed. A new High-Efficiency Centrifugal Compressor stage with a very challenging reduction in radius ratio was successfully designed, fabricated and installed at GRC. The testing was successful, with no mechanical problems and the running clearances were achieved without impeller rubs. Overall, measured pressure ratio of 4.68, work factor of 0.81, and at design exit corrected flow rate of 3 lbm/s met the target requirements. Polytropic efficiency of 85.5 percent and stall margin of 7.5 percent were measured at design flow rate and speed. The measured efficiency and stall margin were lower than pre-test CFD predictions by 2.4 percentage points (pt) and 4.5 pt, respectively. Initial impressions from the experimental data indicated that the loss in the efficiency and stall margin can be attributed to a design shortfall in the impeller. However, detailed investigation of experimental data and post-test CFD simulations of higher fidelity than pre-test CFD, and in particular the unsteady CFD simulations and the assessment with a wider range of turbulence models, have indicated that the loss in efficiency is most likely due to the impact of unfavorable unsteady impeller/diffuser interactions induced by diffuser vanes, an impeller/diffuser corrected flow-rate mismatch (and associated incidence levels), and, potentially, flow separation in the radial-to-axial bend. An experimental program with a vaneless diffuser is recommended to evaluate this observation. A subsequent redesign of the diffuser (and the radial-to-axial bend) is also recommended. The diffuser needs to be redesigned to eliminate the mismatching of the impeller and the diffuser, targeting a slightly higher flow capacity. Furthermore, diffuser vanes need to be adjusted to align the incidence angles, to optimize the splitter vane location (both radially and circumferentially), and to minimize the unsteady interactions with the impeller. The radial-to-axial bend needs to be redesigned to eliminate, or at least minimize, the flow separation at the inner wall, and its impact on the flow in the diffuser upstream. Lessons were also learned in terms of CFD methodology and the importance of unsteady CFD simulations for centrifugal compressors was highlighted. Inconsistencies in the implementation of a widely used two-equation turbulence model were identified and corrections are recommended. It was also observed that unsteady simulations for centrifugal compressors require significantly longer integration times than what is current practice in industry.

Gorazd Medic↗

NASA NTRS2014

High Efficiency Centrifugal Compressor for Rotorcraft Applications

The report "High Efficiency Centrifugal Compressor for Rotorcraft Applications" documents the work conducted at UTRC under the NRA Contract NNC08CB03C, with cost share 2/3 NASA, and 1/3 UTRC, that has been extended to 4.5 years. The purpose of this effort was to identify key technical barriers to advancing the state-of-the-art of small centrifugal compressor stages; to delineate the measurements required to provide insight into the flow physics of the technical barriers; to design, fabricate, install, and test a state-of-the-art research compressor that is representative of the rear stage of an axial-centrifugal aero-engine; and to acquire detailed aerodynamic performance and research quality data to clarify flow physics and to establish detailed data sets for future application. The design activity centered on meeting the goal set outlined in the NASA solicitation-the design target was to increase efficiency at higher work factor, while also reducing the maximum diameter of the stage. To fit within the existing Small Engine Components Test Facility at NASA Glenn Research Center (GRC) and to facilitate component re-use, certain key design parameters were fixed by UTRC, including impeller tip diameter, impeller rotational speed, and impeller inlet hub and shroud radii. This report describes the design effort of the High Efficiency Centrifugal Compressor stage (HECC) and delineation of measurements, fabrication of the compressor, and the initial tests that were performed. A new High-Efficiency Centrifugal Compressor stage with a very challenging reduction in radius ratio was successfully designed, fabricated and installed at GRC. The testing was successful, with no mechanical problems and the running clearances were achieved without impeller rubs. Overall, measured pressure ratio of 4.68, work factor of 0.81, and at design exit corrected flow rate of 3 lbm/s met the target requirements. Polytropic efficiency of 85.5 percent and stall margin of 7.5 percent were measured at design flow rate and speed. The measured efficiency and stall margin were lower than pre-test CFD predictions by 2.4 percentage points (pt) and 4.5 pt, respectively. Initial impressions from the experimental data indicated that the loss in the efficiency and stall margin can be attributed to a design shortfall in the impeller. However, detailed investigation of experimental data and post-test CFD simulations of higher fidelity than pre-test CFD, and in particular the unsteady CFD simulations and the assessment with a wider range of turbulence models, have indicated that the loss in efficiency is most likely due to the impact of unfavorable unsteady impeller/diffuser interactions induced by diffuser vanes, an impeller/diffuser corrected flow-rate mismatch (and associated incidence levels), and, potentially, flow separation in the radial-to-axial bend. An experimental program with a vaneless diffuser is recommended to evaluate this observation. A subsequent redesign of the diffuser (and the radial-to-axial bend) is also recommended. The diffuser needs to be redesigned to eliminate the mismatching of the impeller and the diffuser, targeting a slightly higher flow capacity. Furthermore, diffuser vanes need to be adjusted to align the incidence angles, to optimize the splitter vane location (both radially and circumferentially), and to minimize the unsteady interactions with the impeller. The radial-to-axial bend needs to be redesigned to eliminate, or at least minimize, the flow separation at the inner wall, and its impact on the flow in the diffuser upstream. Lessons were also learned in terms of CFD methodology and the importance of unsteady CFD simulations for centrifugal compressors was highlighted. Inconsistencies in the implementation of a widely used two-equation turbulence model were identified and corrections are recommended. It was also observed that unsteady simulations for centrifugal compressors require significantly longer integration times than what is current practice in industry.

Gorazd Medic↗

NASA NTRS2017

High Efficiency Centrifugal Compressor for Rotorcraft Applications

The report "High Efficiency Centrifugal Compressor for Rotorcraft Applications" documents the work conducted at UTRC under the NRA Contract NNC08CB03C, with cost share 2/3 NASA, and 1/3 UTRC, that has been extended to 4.5 years. The purpose of this effort was to identify key technical barriers to advancing the state-of-the-art of small centrifugal compressor stages; to delineate the measurements required to provide insight into the flow physics of the technical barriers; to design, fabricate, install, and test a state-of-the-art research compressor that is representative of the rear stage of an axial-centrifugal aero-engine; and to acquire detailed aerodynamic performance and research quality data to clarify flow physics and to establish detailed data sets for future application. The design activity centered on meeting the goal set outlined in the NASA solicitation-the design target was to increase efficiency at higher work factor, while also reducing the maximum diameter of the stage. To fit within the existing Small Engine Components Test Facility at NASA Glenn Research Center (GRC) and to facilitate component re-use, certain key design parameters were fixed by UTRC, including impeller tip diameter, impeller rotational speed, and impeller inlet hub and shroud radii. This report describes the design effort of the High Efficiency Centrifugal Compressor stage (HECC) and delineation of measurements, fabrication of the compressor, and the initial tests that were performed. A new High-Efficiency Centrifugal Compressor stage with a very challenging reduction in radius ratio was successfully designed, fabricated and installed at GRC. The testing was successful, with no mechanical problems and the running clearances were achieved without impeller rubs. Overall, measured pressure ratio of 4.68, work factor of 0.81, and at design exit corrected flow rate of 3 lbm/s met the target requirements. Polytropic efficiency of 85.5 percent and stall margin of 7.5 percent were measured at design flow rate and speed. The measured efficiency and stall margin were lower than pre-test CFD predictions by 2.4 percentage points (pt) and 4.5 pt, respectively. Initial impressions from the experimental data indicated that the loss in the efficiency and stall margin can be attributed to a design shortfall in the impeller. However, detailed investigation of experimental data and post-test CFD simulations of higher fidelity than pre-test CFD, and in particular the unsteady CFD simulations and the assessment with a wider range of turbulence models, have indicated that the loss in efficiency is most likely due to the impact of unfavorable unsteady impeller/diffuser interactions induced by diffuser vanes, an impeller/diffuser corrected flow-rate mismatch (and associated incidence levels), and, potentially, flow separation in the radial-to-axial bend. An experimental program with a vaneless diffuser is recommended to evaluate this observation. A subsequent redesign of the diffuser (and the radial-to-axial bend) is also recommended. The diffuser needs to be redesigned to eliminate the mismatching of the impeller and the diffuser, targeting a slightly higher flow capacity. Furthermore, diffuser vanes need to be adjusted to align the incidence angles, to optimize the splitter vane location (both radially and circumferentially), and to minimize the unsteady interactions with the impeller. The radial-to-axial bend needs to be redesigned to eliminate, or at least minimize, the flow separation at the inner wall, and its impact on the flow in the diffuser upstream. Lessons were also learned in terms of CFD methodology and the importance of unsteady CFD simulations for centrifugal compressors was highlighted. Inconsistencies in the implementation of a widely used two-equation turbulence model were identified and corrections are recommended. It was also observed that unsteady simulations for centrifugal compressors require significantly longer integration times than what is current practice in industry.

Centrifugal compressor↗

DOE OSTI2021

A Self-Healable Sulfide/Polymer Composite Electrolyte for Long-Life, Low-Lithium-Excess Lithium-Metal Batteries

Solid electrolyte-protected lithium-metal anodes promise energy-dense, safe cells. While sulfide solid electrolytes enable facile processability and fast ion transport, they suffer from complex chemo-mechanical issues, including Li plating-induced fracture and Li stripping-induced contact loss. To address these issues, a grafting approach is implemented to functionalize the sulfide solid electrolyte (Li 3,85 Sn 0.85 Sb 0.15 S 4 ) with a self-healing unit. This leads to a dynamic bonding between the solid electrolyte network and a mechanically robust polymer scaffold, which reversibly accommodates the volume changes of the lithium-metal anode. Thus, the approach improves the interfacial contact between the lithium-metal anode and the composite electrolyte, enabling stable cycling at a mild stack pressure (160 kPa). With a negative to positive capacity ratio equals to 1, pouch full cells with a high-nickel cathode (nickel content > 90%) and lithium-metal anode display 92% capacity retention for 140 cycles. Engineering the interface between solid electrolyte and the polymeric binder offers a promising pathway to address the chemo-mechanical issues.

36 MATERIALS SCIENCE↗

DOE OSTI2021

Lymphocytic microparticles suppress retinal angiogenesis via targeting Müller cells in the ischemic retinopathy mouse model

Highlights: F0B7 • LMPs possess strong angiogenesis-inhibiting properties. F0B7 • LMPs suppress Müller cell-derived angiogenic/chemoattractant factors. F0B7 • LMPs attenuate pathological retinal NV and the infiltration of macrophages in vivo. F0B7 • LMPs downregulate ERK1/2 and HIF-1α both in vitro and in vivo. Retinopathy of prematurity (ROP) is the primary cause of visual impairment and vision loss in premature infants, which results from the formation of aberrant retinal neovascularization (NV). An emerging body of evidence has shown that Müller cells are the predominant source of vascular endothelial growth factor (VEGF), which also serves as a chemoattractant for monocyte/macrophage lineage. The recruitment of macrophages is increased during retinal NV, and they exert a pro-angiogenic role in ROP. We have shown that lymphocytic microparticles (microvesicles; LMPs) derived from apoptotic human T lymphocytes possess strong angiogenesis-inhibiting properties. Here, we investigated the effect of LMPs on the chemotactic capacity of Müller cells in vitro using rat Müller cell rMC-1 and mouse macrophage RAW 264.7. In addition, the impact of LMPs was determined in vivo using a mouse model of oxygen-induced ischemic retinopathy (OIR). The results revealed that LMPs were internalized by rMC-1 and reduced their cell proliferation dose-dependently without inducing cell apoptosis. LMPs inhibited the chemotactic capacity of rMC-1 on RAW 264.7 via reducing the expression of VEGF. Moreover, LMPs attenuated pathological retinal NV and the infiltration of macrophages in vivo. LMPs downregulated ERK1/2 and HIF-1α both in vitro and in vivo. These findings expand our understanding of the effects of LMPs, providing evidence of LMPs as a promising therapeutic approach for the treatment of retinal NV diseases.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2025

A Quasi-Ordered Mn-Rich Cathode with Highly Reversible Oxygen Anion Redox Chemistry

Anionic oxygen redox chemistry in Li-rich Mn-based layer oxide cathodes represents a transformative approach for boosting the energy density of next-generation lithium-ion batteries. However, conventional oxygen redox reactions often induce oxygen dimerization at high voltages, leading to irreversible lattice oxygen loss and a rapid voltage fade. Herein, we achieve highly reversible oxygen redox chemistry through a new quasi-ordered structural design that incorporates both intra- and interlayer cation disorder configurations. This unique structure significantly enhances lattice oxygen stability, effectively stabilizes oxidized oxygen, and inhibits the formation of peroxo- or superoxol-like species, thereby enabling anionic redox reactions to proceed reversibly even at deep delithiation states. The quasi-ordered design mitigates irreversible phase transitions and preserves the structural integrity throughout extended cycling. Consequently, the proposed cathode demonstrates exceptional cyclability with negligible capacity and voltage fade, retaining 99% capacity and 98% average voltage after long-term cycling. Finally this work provides fresh insights into addressing issues related to lattice oxygen instabilities and reforming strategies for developing long-life, high-energy-density anionic redox cathode materials for advanced batteries.

chemical structure↗

DOE OSTI2024

Stabilizing LiCoO 2 at 4.6 V by regulating anti-oxidative solvents

For LiCoO 2 (LCO) operating at high voltages (>4.5 V vs. Li/Li + ), the intensive side reactions between LCO and traditional ethylene carbonate (EC)-based electrolytes with LiPF 6 salts can produce plenty of corrosive species (such as HF and HPO 2 F 2 ), causing severe surface degradation. Herein, anti-oxidative fluoroethylene carbonate (FEC) and difluoroethylene carbonate (DFEC) were selected as co-solvents to reduce the generation of corrosive species. Besides, PF 6 − anions enrich the Helmholtz plane of the LCO/electrolyte interface and promote the formation of a robust cathode/electrolyte interphase (CEI) featuring LiF/Li x PO y F z /Li 3 PO 4 inorganics and P-containing organics under the synergy of fluorinated solvents, which significantly inhibits the catalysis of highly oxidative Co 4+ /O n− (0 < n < 2). Benefiting from the reduced corrosive species and reinforced CEI, the layered structure of the LCO surface is well preserved during long-term cycling, with a highly reversible O3/H1-3 phase transition. Consequently, a LCO||graphite pouch cell exhibits a remarkable capacity retention of 85.7% after 500 cycles in 3.0–4.55 V. Furthermore, this work provides a new insight into developing advanced functional electrolytes for high-voltage lithium-ion batteries.

Co/O loss↗

DOE OSTI2023

Designing Li 4 Ti 5 O 12 /LiMn 2 O 4 Cells: Negative-to-Positive Ratio and Electrolyte

Li 4 Ti 5 O12/LiMn2O 4 (LTO/LMO) system is a promising candidate for behind-the-meter storage (BTMS) applications due to its critical-material-free chemistry exhibiting good safety and long lifetime. In this paper we design LTO/LMO cells to mitigate their major degradation mechanism, loss of Li inventory, and improve their long-term cyclability. First, LMO electrodes with different loadings (2.61, 3.29, and 4.26 mAh cm -2 ) are paired with an LTO electrode (3.35 mAh cm -2 ) to create varying negative-to-positive ratios (N/P>1, =1, and <1). Additionally, conventional ethylene carbonate (EC)/ethyl methyl carbonate (EMC) mixture electrolyte and safety enhanced EC-only electrolyte are examined. We show that storing additional Li inventory in the cathode (i.e., using a thicker electrode and having N/P<1) is a convenient method to enhance the capacity retention of LTO/LMO cells, but only if the electrode utilization is not limited by the Li + ion transport. For systems that suffer from limited transport properties, prelithiating the anode will be more effective since LTO (~165 mAh g -1 LTO ) can store the same amount of capacity using less material compared to LMO (~100 mAh g -1 LMO ). In this work, we demonstrate how the electrolyte properties and the electrode thickness of LTO/LMO cells can be designed to enhance their performance.

25 ENERGY STORAGE↗

DOE OSTI2023

Progresses and Perspectives of All‐Iron Aqueous Redox Flow Batteries

Abstract Redox flow batteries (RFBs) are a promising option for long‐duration energy storage (LDES) due to their stability, scalability, and potential reversibility. However, solid‐state and non‐aqueous flow batteries have low safety and low conductivity, while aqueous systems using vanadium and zinc are expensive and have low power and energy densities, limiting their industrial application. An approach to lower capital cost and improve scalability is to utilize cheap Earth‐abundant metals such as iron (Fe). Nevertheless, all‐iron RFBs have many complications, involving voltage loss from ohmic resistance, side reactions such as hydrogen evolution, oxidation, and most significantly electrode plating, and dendrite growth. To address these issues, researchers have begun to examine the effects of various alterations to all‐iron RFBs, such as adding organic ligands to form Fe complexes and using a slurry electrode instead of common materials such as graphite or platinum rods. Overall, progress in improving aqueous all‐iron RFBs is at its infant stage, and new strategies must be introduced, such as the utilization of nanoparticles, which can limit dendrite growth while increasing storage capacity. This review provides an in‐depth overview of current research and offers perspectives on how to design the next generation of all‐iron aqueous RFBs.

Belongia, Shawn↗

DOE OSTI2025

Electrocatalytic grafting of polyvinyl chloride plastics

Polyvinyl chloride (PVC) plastics require high loadings of plasticizers and stabilizers to achieve commercially useful bulk properties. However, these non-covalent additives leach from PVC over time, resulting in the loss of their tailored functionality. This work details the electrocatalytic functionalization of PVC to covalently graft plasticizing additives directly onto the polymer backbone. Here, mechanistic insights guided the design of electrocatalysts capable of modifying C–Cl bonds of PVC under mild conditions with high selectivity while suppressing side reactions such as elimination and chain scission. Functional groups that mimic PVC plasticizers are covalently installed into the backbone of PVC to create new materials with distinct bulk properties from the original polymer. The degree of polymer grafting is easily controlled by simply changing the redox capacity that is passed during electrolysis. This strategy is employed to create chemically- and leach-resistant PVC materials by directly electrolyzing mixtures of consumer PVC products

Zackasee, Jordan L.S.↗