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DOE OSTI2024

Decoupling first-cycle capacity loss mechanisms in sulfide solid-state batteries

Solid-state batteries (SSBs) promise more energy-dense storage than liquid electrolyte lithium-ion batteries (LIBs). However, first-cycle capacity loss is higher in SSBs than in LIBs due to interfacial reactions. The chemical evolution of key interfaces in SSBs has been extensively characterized. Electrochemically, however, we lack a versatile strategy for quantifying the reversibility of solid electrolyte (SE) redox for established and next-generation SSB electrolytes. In this work, we perform tailored electrochemical tests and operando X-ray diffraction to disentangle reversible and irreversible sources of capacity loss in positive electrodes composed of Li 6 PS 5 Cl SE, Li(Ni 0.5 Mn 0.3 Co 0.2 )O 2 (NMC), and carbon conductive additives. We leverage an atypically low voltage cutoff (2.0 V vs. Li/Li + ) to quantify the reversibility of SE redox. Using slow (5.5 mA g NMC −1 ) cycling paired with >100 h low-voltage holds, our cells achieve a surprising 96.2% first-cycle coulombic efficiency, which is higher than previously reported (mean: 72%, maximum: 91.6% across surveyed literature). We clarify that sluggish NMC relithiation kinetics have been historically mistaken for permanently irreversible capacity loss. In conclusion, through systematic decoupling of loss mechanisms, we uncover the unexpected reversibility of SE redox and isolate the major contributors to capacity loss, outlining a strategy for accurate assessment of next-generation SE materials and interface modifications.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2024

Intercalation of quaternary ammonium cations as a key factor of electron storage in MoS2 thin films

Electrochemical intercalation of cations within two-dimensional transition metal dichalcogenides presents a promising route for tailoring their optoelectronic properties. We have now succeeded in modulating the optical properties of MoS2 thin films through electrochemical intercalation of quaternary ammonium cations. The spectroelectrochemical experiments conducted with varying sizes of the intercalant revealed the size-dependent stability of the intercalated MoS2 nanosheets. The observed absorption change of the exciton bands is reversible and arises from the storage of electrons in MoS2 nanosheets and the subsequent weakening of interlayer van der Waals interactions following cation intercalation. This structural change is evidenced by the emergence of A*1g out-of-plane Raman mode. Additionally, the photoelectron spectroscopy reveals the emergence of a lower binding energy component of Mo 3d and the shift in Fermi level to higher energies, confirming the presence of stored electrons in cation intercalated-MoS2. The underlying mechanism of intercalation-induced property modifications in MoS2 discussed in the present study is useful in developing strategies for energy conversion devices.

Physics↗

DOE OSTI2020

Fluorinated Covalent Organic Frameworks: A Novel Pathway to Enhance Hydrogen Sorption and Control Isosteric Heats of Adsorption; HyMARC Seed Project Final Report

Organic framework materials, as a unique sub-class of carbon-based sorbents, have gained increasing attention for promising attributes toward gas storage. Calculations of the hydrogen capacity of optimized frameworks show potential to achieve greater than 60 g/L storage of hydrogen, placing metal-organic frameworks (MOFs) and COFs near the top of the class of porous materials. However, at the ensemble level, poor stacking creates a quasi-amorphous material with low structural integrity and low effective surface area. The chemical versatility of COFs allows for additional methods for producing long-range order that specifically target the inter-layer interactions in COFs but that leave key pore-accessible linker sites open. These modifications (either during synthesis or post-synthetic) enable a host of strategies to both improve crystalline order for more stable and higher surface, as well as add metals with open coordination for enhanced H 2 binding enthalpy.

08 HYDROGEN↗

DOE OSTI2020

Interlaboratory Study for Characterizing Monoclonal Antibodies by Top-Down and Middle-Down Mass Spectrometry

The Consortium for Top-Down Proteomics (www.topdownproteomics.org) launched the present study to assess the state of top-down mass spectrometry (TD MS) and middle-down mass spectrometry (MD MS) for characterizing monoclonal antibody (mAb) primary structures, including their modifications. To meet the needs of the rapidly growing therapeutic antibody market, it is important to develop analytical strategies to characterize the heterogeneity of a therapeutic product’s primary structure reliably and reproducibly. The major objective of the present study was to determine whether current TD/MD MS technologies and protocols can add value to the more commonly employed bottom-up approaches, such as confirming protein integrity, sequencing variable domains, ruling out artefacts, and revealing modifications and their locations. A panel of three mAbs was selected and centrally provided to twenty laboratories worldwide for the analysis: Sigma mAb standard (SiLuLite), NIST mAb standard, and the therapeutic mAb Herceptin (trastuzumab). A variety of different MS instrument platforms and ion dissociation techniques were employed. Overall, the present study confirms that MD/TD MS strategies are valuable and readily available tools in laboratories worldwide. They provide complementary information to the bottom-up approach and can add unique information, which may be crucial for comprehensive mAb characterization. The current limitations, as well as possible solutions to overcome them, are also outlined. One of the limitations revealed by the results of the present study is that the expert knowledge in both experiment and data analysis is indispensable to practice TD/MD MS, but the number of TD/MD MS experts is still very low.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2025

Technical Routes to Achieve High Circular Polarized Luminescence in Chiral Perovskites: A Mini‐Review

Chiral hybrid organic-inorganic perovskites (HOIPs) have emerged as promising materials for optoelectronic and spintronic applications, leveraging unique properties such as circularly polarized luminescence (CPL), circularly polarized nonlinear optical (NLO) emission, and chiral-induced spin selectivity (CISS). However, challenges remain in stabilizing these materials under environmental stresses and precisely controlling chirality for scalable use. This review summarizes five main strategies to induce chirality in HOIPs, i.e., direct incorporation of chiral cations, surface modification with chiral ligands, ion doping, template-induced chirality, and chiral metasurfaces. Each approach offers distinct advantages for optimizing CPL efficiency and device stability, paving the way for next-generation applications in CPL detectors, information encryption, spintronic devices, etc.

14 SOLAR ENERGY↗

DOE OSTI2025

Advances in Carbon Electrode Integration for Stable and Efficient Perovskite Solar Cells and Modules

Carbon-electrode-based perovskite solar cells (C-PSCs) have emerged as a cost-effective and scalable alternative to noble-metal-based PSCs, addressing critical challenges related to device stability, fabrication complexity, and commercialization potential. This review explores the recent progress in C-PSC development, focusing on the benefits of carbon electrodes (CEs), including their hydrophobicity, chemical inertness to halide corrosion, and compatibility with low-temperature cost-effective solution-based deposition methods. Despite relatively lower power conversion efficiencies (PCEs) than their metal (e.g., Au/Ag) counterparts, recent advances in carbon paste formulation, interfacial contact engineering, and work function modification have elevated C-PSC efficiencies above 22%. This review further examines strategies to enhance electrode conductivity, interfacial properties, and charge selectivity to further increase C-PSC performance. Progress in carbon-electrode-based perovskite solar modules (C-PSMs), particularly within mesoporous and planar architectures, is also analyzed, revealing significant developments in active area scaling and long-term stability. Notably, the limited research in inverted (PIN) C-PSCs is also highlighted as a compelling opportunity for innovation, given the architecture's inherent advantages in flexibility, tandem integration, and low-temperature processing. Collectively, these insights affirm the potential of C-PSCs and C-PSMs to deliver affordable, stable, and high-performance photovoltaics suitable for scalable deployment.

Carbon Electrodes↗

DOE OSTI2022

Modelica-based modeling and simulation of district cooling systems: A case study

While equation-based object-oriented modeling language Modelica can evaluate practical energy improvements for district cooling systems, few have adopted Modelica for this type of large-scale thermo-fluid system. Further, to our best knowledge, district cooling modeling studies have yet to include hydraulics in piping networks alongside plant models featuring realistic mechanical systems and controls. These are critical details to include when looking to make energy and control improvements in many physical system installations. To fill these gaps, this study released new open-source district cooling models at the Modelica Buildings Library and leveraged these models for a real-world case study at the University of Colorado Boulder. Here, the site includes six buildings connected to a central chiller plant featuring a waterside economizer. Several energy saving strategies are pursued based on the validated model, including control setpoint optimization, equipment modification, and pump setpoint adjustments. Results indicate that a combination of the studied measures can save the campus annually 84.6 MWh of energy, 8.9% of electricity costs, 58.0 metric tons of carbon dioxide emissions, while the waterside economizer cuts down chillers’ run times by 201 days/year, reducing maintenance costs and extending chiller life.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

DOE OSTI2020

Rechargeable alkaline zinc–manganese oxide batteries for grid storage: Mechanisms, challenges and developments

Rechargeable alkaline Zn–MnO 2 (RAM) batteries are a promising candidate for grid-scale energy storage owing to their high theoretical energy density rivaling lithium-ion systems (~400 Wh/L), relatively safe aqueous electrolyte, established supply chain, and projected costs below $100/kWh at scale. In practice, however, many fundamental chemical and physical processes at both electrodes make it difficult to achieve commercially competitive energy density and cycle life. In this paper, we present a detailed and timely analysis of the constituent materials, current commercial status, electrode processes, and performance-limiting factors of RAM batteries. We also examine recently reported strategies in RAM and related systems to address these issues through additives and modifications to the electrode materials and electrolyte, special ion-selective separators and/or coatings, and unconventional cycling protocols. We conclude with a critical summary of these developments and discussion of how future studies should be focused toward the goal of energy-dense, scalable, and cost-effective RAM systems.

25 ENERGY STORAGE↗

DOE OSTI2022

Charge transport and antiferromagnetic ordering in nitroxide radical crystals

Nonconjugated radical polymers and small molecules are employed as functional materials in organic electronic devices. Furthermore, the unpaired electrons on these materials have permanent magnetic moments, making these materials promising candidates for organic magnets. Through molecular design, strong antiferromagnetic and ferromagnetic ordering have been achieved in conjugated materials. However, the magnetic properties of nonconjugated radical polymers have only shown weak magnetic interactions among the open-shell sites due to the large mean separation between radicals in typical materials. Here, we have designed, synthesized, and crystalized two open-shell molecules that used molecular engineering to control the assembly of the open-shell sites into a strong antiferromagnetically ordered network. The strong antiferromagnetic interaction is evidenced by a high paramagnetic-to-antiferromagnetic transition temperature of ~40 K. This high transition temperature was a result of a high spin exchange coupling constant J of about –20 cm –1 , which was suggested by both experimental and computed coupling parameters given by the energy difference between high-spin and low-spin broken-symmetry structures. In addition, a single-crystal electrical conductivity of ~10 –3 S m –1 was achieved, which indicated the potential of this material in electronic applications. As a result, this work provides an insight into a design strategy for radical-based electronic and magnetic materials through proper molecular structure modifications.

36 MATERIALS SCIENCE↗

DOE OSTI2024

Tilted lidar profiling: Development and testing of a novel scanning strategy for inhomogeneous flows

The most common profiling techniques for the atmospheric boundary layer based on a monostatic Doppler wind lidar rely on the assumption of horizontal homogeneity of the flow. This assumption breaks down in the presence of either natural or human-made obstructions that can generate significant flow distortions. The need to deploy ground-based lidars near operating wind turbines for the American WAKE experimeNt (AWAKEN) spurred a search for novel profiling techniques that could avoid the influence of the flow modifications caused by the wind farms. With this goal in mind, two well-established profiling scanning strategies have been retrofitted to scan in a tilted fashion and steer the beams away from the more severely inhomogeneous region of the flow. Results from a field test at the National Renewable Energy Laboratory's 135-m meteorological tower show that the accuracy of the horizontal mean flow reconstruction is insensitive to the tilt of the scan, although higher-order wind statistics are severely deteriorated at extreme tilts mainly due to geometrical error amplification. A numerical study of the AWAKEN domain based on the Weather Research and Forecasting Model and large-eddy simulation are also conducted to test the effectiveness of tilted profiling. It is shown that a threefold reduction of the error on inflow mean wind speed can be achieved for a lidar placed at the base of the turbine using tilted profiling.

17 WIND ENERGY↗

DOE OSTI2022

Cell wall ester modifications and volatile emission signatures of plant response to abiotic stress

Abstract Growth suppression and defence signalling are simultaneous strategies that plants invoke to respond to abiotic stress. Here, we show that the drought stress response of poplar trees ( Populus trichocarpa ) is initiated by a suppression in cell wall derived methanol (MeOH) emissions and activation of acetic acid (AA) fermentation defences. Temperature sensitive emissions dominated by MeOH (AA/MeOH <30%) were observed from physiologically active leaves, branches, detached stems, leaf cell wall isolations and whole ecosystems. In contrast, drought treatment resulted in a suppression of MeOH emissions and strong enhancement in AA emissions together with volatiles acetaldehyde, ethanol, and acetone. These drought‐induced changes coincided with a reduction in stomatal conductance, photosynthesis, transpiration, and leaf water potential. The strong enhancement in AA/MeOH emission ratios during drought (400%–3500%) was associated with an increase in acetate content of whole leaf cell walls, which became significantly 13 C 2 ‐labelled following the delivery of 13 C 2 ‐acetate via the transpiration stream. The results are consistent with both enzymatic and nonenzymatic MeOH and AA production at high temperature in hydrated tissues associated with accelerated primary cell wall growth processes, which are downregulated during drought. While the metabolic source(s) require further investigation, the observations are consistent with drought‐induced activation of aerobic fermentation driving high rates of foliar AA emissions and enhancements in leaf cell wall O ‐acetylation. We suggest that atmospheric AA/MeOH emission ratios could be useful as a highly sensitive signal in studies investigating environmental and biological factors influencing growth‐defence trade‐offs in plants and ecosystems.

59 BASIC BIOLOGICAL SCIENCES↗

DOE OSTI2020

Random Polymerization Strategy Leads to a Family of Donor Polymers Enabling Well‐Controlled Morphology and Multiple Cases of High‐Performance Organic Solar Cells

Abstract Developing high‐performance donor polymers is important for nonfullerene organic solar cells (NF‐OSCs), as state‐of‐the‐art nonfullerene acceptors can only perform well if they are coupled with a matching donor with suitable energy levels. However, there are very limited choices of donor polymers for NF‐OSCs, and the most commonly used ones are polymers named PM6 and PM7, which suffer from several problems. First, the performance of these polymers (particularly PM7) relies on precise control of their molecular weights. Also, their optimal morphology is extremely sensitive to any structural modification. In this work, a family of donor polymers is developed based on a random polymerization strategy. These polymers can achieve well‐controlled morphology and high‐performance with a variety of chemical structures and molecular weights. The polymer donors are D–A1–D–A2‐type random copolymers in which the D and A1 units are monomers originating from PM6 or PM7, while the A2 unit comprises an electron‐deficient core flanked by two thiophene rings with branched alkyl chains. Consequently, multiple cases of highly efficient NF‐OSCs are achieved with efficiencies between 16.0% and 17.1%. As the electron‐deficient cores can be changed to many other structural units, the strategy can easily expand the choices of high‐performance donor polymers for NF‐OSCs.

Liang, Jiaen↗

DOE OSTI2026

Pressurized Gas-Driven Elemental Redistribution Enables Ultrastable PtNi Catalysts for Heavy-Duty Vehicles

Gas-driven element redistribution, characterized by the preferential enrichment of one element at the surface relative to the bulk, is frequently observed in multicomponent alloys. Using L1 0 -ordered PtNi as a model system, we reveal that gas pressure plays a critical role in governing adsorption-driven surface composition during annealing in reducing gases: low pressure favors Pt surface segregation, while high pressure facilitates Ni surface enrichment. In this study, we developed a high-pressure nitriding (HPN) strategy that modulates the surface structure and composition of PtNi catalysts. The resulting HPN-PtNi exhibits enhanced performance and durability in membrane electrode assemblies for heavy-duty fuel cell applications, maintaining a high current density of 1.19 A cm −2 at 0.7 V after 90,000 voltage cycles. Through a combination of experimental and theoretical analyses, we reveal that the HPN process forms additional stabilizing Ni−N bonds and induces elemental redistribution with Ni surface enrichment and a Ni-deficient Pt subsurface. These modifications alter the atomic coordination environment of the ordered PtNi phase. This work presents a generalizable strategy to design robust and high-performing Pt-based catalysts by controlling gas-pressure-driven elemental redistribution and dopant incorporation.

30 DIRECT ENERGY CONVERSION↗

DOE OSTI2024

Advancing the Performance of Lithium-Rich Oxides in Concert with Inherent Complexities: Domain-Selective Substitutions

Historically, modifications to Li- and Mn-rich (LMR) cathodes have been studied in relation to their efficacy in solving challenges such as oxygen loss and voltage fade, which are inherent to the activation process of these electrodes. However, even in the presence of these phenomena, well-optimized LMR cathodes show considerable promise as earth-abundant options, particularly if other barriers to implementation can be overcome or mitigated. As the complex mechanisms of LMR electrodes are known to stem from the local, chemical inhomogeneities that define the nanocomposite domain nature of these oxides, strategies aimed at manipulating the performance of activated electrodes, irrespective of voltage fade, through domain-selective modifications, could prove instructive. In this work, we use a novel synthesis process aimed at influencing the site occupancy of substituted Sn 4+ , as an example 4+ cation, into a Co-free Li 1.13 Mn 0.57(1–x) Sn 0.57x Ni 0.3 O 2 LMR oxide. We show that Sn 4+ can be selectively substituted into Li-rich environments. The consequences are revealed to be both chemical and morphological, and the domain-selective doping strategy provides a knob for directed control of the low state-of-charge impedance behavior. In conclusion, these results reveal new clues and insights with respect to further advancing the practical relevance of LMR cathode particles and electrodes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2020

Novel tools and observables for jet physics in heavy-ion collisions

Abstract Studies of fully-reconstructed jets in heavy-ion collisions aim at extracting thermodynamical and transport properties of hot and dense QCD matter. Recently, a plethora of new jet substructure observables have been theoretically and experimentally developed that provide novel precise insights on the modifications of the parton radiation pattern induced by a QCD medium. This report, summarizing the main lines of discussion at the 5th Heavy Ion Jet Workshop and CERN TH institute ‘Novel tools and observables for jet physics in heavy-ion collisions’ in 2017, presents a first attempt at outlining a strategy for isolating and identifying the relevant physical processes that are responsible for the observed medium-induced jet modifications. These studies combine theory insights, based on the Lund parton splitting map, with sophisticated jet reconstruction techniques, including grooming and background subtraction algorithms.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2021

Optimized molecular aggregation via incorporating fluorinated unit in the polymer donor for 17.3% efficiency organic solar cells

Regulating molecular aggregation state via chemical modification of photovoltaic materials to optimize the blend morphology is an effective and challenging strategy to improve the photovoltaic performance of organic solar cells (OSCs). Here, in this work, we demonstrate a random terpolymerization strategy by incorporating 1,3-bis(5-bromo-4-fluorothiophen-2-yl)-5,7-bis(2-ethylhexyl)-4H,8H-benzo[1,2-c:4,5-c']bisthiophene-4,8-dione (BFT, 30 mol%) unit with fluorinated π-bridges into the molecular backbone of PM6 and develop a terpolymer PF1. Benefiting from the strong electronegativity of fluorine atom and noncovalent interaction of F---S, the energy levels, molecular ordering, and aggregation properties of the polymer donors are precisely regulated. Notably, in the active layer film based on PF1: Y6, the π-π stacking distance can reduce to 3.51 Å, which is significantly smaller than that of PM6:Y6 (3.65 Å) and boosts the effective exciton dissociation and charge transport, thereby effectively optimize the photovoltaic properties of the related devices. As a result, the PF1:Y6-based OSCs achieved a power conversion efficiency (PCE) of up to 17.3%, which is much higher than that of the controlled OSCs based on PM6:Y6 (PCE = 16.2%). These results demonstrate high-efficiency OSCs enabled by regulating molecular aggregation via terpolymerization strategy.

14 SOLAR ENERGY↗

DOE OSTI2023

Stabilizing Ni-rich layered cathode for high-voltage operation through hierarchically heterogeneous doping with concentration gradient

High-nickel LiNi x Mn y Co 1-x-y O 2 (NMC) cathodes have demonstrated superior energy density, yet their stability is compromised under high voltage conditions. To address this, here we propose a strategy of heterogeneous doping with a concentration gradient, specifically through Sr–Zr co-modification. We synthesized Ni-rich NMC particles featuring several micron-sized secondary particles composed of micron-sized primary grains. This design aims to harness the structural robustness of single-crystalline grains and the favorable diffusion kinetics of polycrystalline secondary particles. Systematic characterization using a combination of electrochemical measurements and synchrotron analytics reveals an intriguing pattern of hierarchically heterogeneous Sr–Zr co-doping. It demonstrates a depth-dependent concentration gradient at the secondary particle level and competing dopant segregation over the buried grain boundaries. This unique characteristic creates opportunities for enhancing battery performance, particularly by optimizing precursors and implementing advanced modulation techniques. We also investigate the dissolution and precipitation of the cathode's transition metal cations upon high-voltage cycling. These insights suggest that a tailored compositional variation can be a viable approach to effectively design the next-generation high-Ni NMC cathode materials for high-voltage lithium batteries.

36 MATERIALS SCIENCE↗

DOE OSTI2021

Structural modification of fentanyls for their retrospective identification by gas chromatographic analysis using chloroformate chemistry

Abstract The one-step breakdown and derivatization of a panel of nine fentanyls to yield uniquely tagged products that can be detected by Electron Ionization Gas Chromatography-Mass Spectrometry (EI-GC-MS) is presented. The method involves the treatment of the synthetic opioids with 2,2,2-trichloroethoxycarbonyl chloride (TrocCl) at 60 °C for 3 h in dichloromethane and furnishes two products from one fentanyl molecule that can be used to retrospectively identify the original opioid. Parameters that were studied and fully optimized for the method included temperature, solvent, nature of scavenging base and reaction time. One of the two resulting products from the reaction bears the trichloroethoxycarbonyl (Troc) tag attached to the norfentanyl portion of the original opioid and greatly aids in the opioid detection and identification process. The methodology has been applied to the chemical modification of a panel of nine fentanyls and in all cases the molecular ion peak for the Troc-norfentanyl product bearing the distinctive trichloroethyl isotopic signature can be clearly observed. The method’s LLOD was determined to be 10 ng/mL while its LLOQ was found to be 20 ng/mL. This methodology represents the first application of chloroformates in the chemical modification of this class of synthetic opioids that are notoriously inert to common derivatization strategies available for GC–MS analysis.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗