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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 757 records · Page 42
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Manganese‐Based Spinel Cathodes: A Promising Frontier for Solid‐State Lithium‐Ion Batteries

Recently, all-solid-state lithium-ion batteries (ASSLIBs), which exhibit improved safety and enhanced energy density compared to conventional commercialized lithium-ion batteries (LIBs), thereby have garnered extensive research interest. Among the promising cathode candidates, Mn-based spinel cathodes LiMn 2 O 4 (LMO) and LiNi 0.5 Mn 1.5 O 4 (LNMO), with the unique characteristics of low cost, structural stability, and 3D Li-ion diffusion channels, have demonstrated excellent performance in LIBs and presented great potential in ASSLIBs applications. However, several challenges, including structural degradations, poor interfacial contact, large interfacial resistance, and Mn-dissolution/diffusion during the electrochemical cycling, hinder their practical applications and commercialization in the ASSLIBs. Particularly, the high-voltage LNMO cathodes suffer from the challenge of electrochemical incompatibility with most of the solid-state electrolytes (SSEs). Herein, the spinel structure, the electrochemical behavior, and the structural degradation of the LMO/LNMO are explored. The characteristics and recent progress of the mitigating strategies to the challenges of various SSEs, including polymer-, oxide-, composite-, sulfide-, halide-, and LiPON-based SSEs, are introduced when paired with LMO/LNMO. Finally, the directions for future research to advance Mn-based spinel cathodes and fulfill the requirements of the next-generation ASSLIBs are also discussed.

Dou, Yu [Concordia University, Montreal, QC (Canad↗
DOE OSTI2022

Ferromagnetic Double Perovskite Semiconductors with Tunable Properties

Abstract The authors successfully dope the magnetically silent double perovskite semiconductor Sr 2 GaSbO 6 to induce ferromagnetism and tune its bandgap, with Ga 3+ partially substituted by the magnetic trivalent cation Mn 3+ , in a rigid cation ordering with Sb 5+ . The new ferromagnetic semiconducting Sr 2 Ga 1− x Mn x SbO 6 double perovskite, which crystallizes in tetragonal symmetry (space group I 4/ m ) and has tunable ferromagnetic ordering temperature and bandgap, suggests that magnetic ion doping of double perovskites is a productive avenue toward obtaining materials for application in next‐generation oxide‐based spintronic devices.

36 MATERIALS SCIENCE↗
DOE OSTI2022

A Fast‐Charging and High‐Temperature All‐Organic Rechargeable Potassium Battery

Abstract Developing fast‐charging, high‐temperature, and sustainable batteries is critical for the large‐scale deployment of energy storage devices in electric vehicles, grid‐scale electrical energy storage, and high temperature regions. Here, a transition metal‐free all‐organic rechargeable potassium battery (RPB) based on abundant and sustainable organic electrode materials (OEMs) and potassium resources for fast‐charging and high‐temperature applications is demonstrated. N‐doped graphene and a 2.8 m potassium hexafluorophosphate (KPF 6 ) in diethylene glycol dimethyl ether (DEGDME) electrolyte are employed to mitigate the dissolution of OEMs, enhance the electrode conductivity, accommodate large volume change, and form stable solid electrolyte interphase in the all‐organic RPB. At room temperature, the RPB delivers a high specific capacity of 188.1 mAh g −1 at 50 mA g −1 and superior cycle life of 6000 and 50000 cycles at 1 and 5 A g −1 , respectively, demonstrating an ultra‐stable and fast‐charging all‐organic battery. The impressive performance at room temperature is extended to high temperatures, where the high‐mass‐loading (6.5 mg cm −2 ) all‐organic RPB exhibits high‐rate capability up to 2 A g −1 and a long lifetime of 500 cycles at 70–100 °C, demonstrating a superb fast‐charging and high‐temperature battery. The cell configuration demonstrated in this work shows great promise for practical applications of sustainable batteries at extreme conditions.

25 ENERGY STORAGE↗
DOE OSTI2022

Thermal Runaway of Nonflammable Localized High‐Concentration Electrolytes for Practical LiNi 0.8 Mn 0.1 Co 0.1 O 2 |Graphite‐SiO Pouch Cells

Abstract With continuous improvement of batteries in energy density, enhancing their safety is becoming increasingly urgent. Herein, practical high energy density LiNi 0.8 Mn 0.1 Co 0.1 O 2 |graphite‐SiO pouch cell with nonflammable localized high concentration electrolyte (LHCE) is proposed that presents unique self‐discharge characteristic before thermal runaway (TR), thus effectively reducing safety hazards. Compared with the reference electrolyte, pouch cell with nonflammable LHCE can increase self‐generated heat temperature by 4.4 °C, increase TR triggering temperature by 47.3 °C, decrease the TR highest temperature by 71.8 °C, and extend the time from self‐generated heat to triggering TR by ≈8 h. In addition, the cell with nonflammable LHCE presents superior high voltage cycle stability, attributed to the formation of robust inorganic‐rich electrode–electrolyte interphase. The strategy represents a pivotal step forward for practical high energy and high safety batteries.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Chemical Profiles of the Oxides on Tantalum in State of the Art Superconducting Circuits

Abstract Over the past decades, superconducting qubits have emerged as one of the leading hardware platforms for realizing a quantum processor. Consequently, researchers have made significant effort to understand the loss channels that limit the coherence times of superconducting qubits. A major source of loss has been attributed to two level systems that are present at the material interfaces. It is recently shown that replacing the metal in the capacitor of a transmon with tantalum yields record relaxation and coherence times for superconducting qubits, motivating a detailed study of the tantalum surface. In this work, the chemical profile of the surface of tantalum films grown on c‐plane sapphire using variable energy X‐ray photoelectron spectroscopy (VEXPS) is studied. The different oxidation states of tantalum that are present in the native oxide resulting from exposure to air are identified, and their distribution through the depth of the film is measured. Furthermore, it is shown how the volume and depth distribution of these tantalum oxidation states can be altered by various chemical treatments. Correlating these measurements with detailed measurements of quantum devices may elucidate the underlying microscopic sources of loss.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Order–Disorder Phase Stabilization by Pressure‐Induced Charge Transfer Enhances the Ferroelectric Photovoltaic Effect in Multiferroic BaFe 4 O 7

Abstract Multiferroic ferroelectric photovoltaic (FPV) materials, combining magnetic and ferroelectric properties, are of paramount importance for optoelectronic and photovoltaic applications. However, optimizing both the remanent polarization and the optical bandgap—key factors for enhanced FPV performance—presents a significant challenge due to their trade‐off. This work shows that pressure‐induced charge transfer between different metal sites can break this trade‐off. Above ≈20 GPa, charge transfer between different trivalent iron (Fe) sites in the multiferroic material BaFe 4 O 7 leads to Fe valence disproportionation, FeO 4 tetrahedra disorder, and Jahn–Teller distortion of FeO 6 octahedra. These changes reduce the bandgap, lower resistivity, and enhance ferroelectric polarization, resulting in a 2.5‐fold increase in photocurrent. Upon decompression, BaFe 4 O 7 retains an order–disorder structure, optimal ferroelectric and optical properties at ambient conditions. This work provides a novel pathway to simultaneously optimizing ferroelectricity and bandgap via pressure‐induced charge transfer, overcoming the traditional trade‐off in FPV materials, and offers a promising approach for developing high polarization performance, narrow‐bandgap FPV materials.

Chemistry↗
DOE OSTI2018

Challenges in Developing Electrodes, Electrolytes, and Diagnostics Tools to Understand and Advance Sodium-Ion Batteries

Here, considering the natural abundance and low cost of sodium resources, sodium-ion batteries (SIBs) have received much attention for large-scale electrochemical energy storage. However, smart structure design strategies and good mechanistic understanding are required to enable advanced SIBs with high energy density. In recent years, the exploration of advanced cathode, anode and electrolyte materials as well as advanced diagnostics have been extensively carried out. This review mainly focused on the challenging problems for the attractive battery materials (i.e. cathode, anode and electrolytes) and summarized the latest strategies to improve their electrochemical performance as well as presented recent progress of operando diagnostics to disclose the physic behind the electrochemical performance, and to provide guidance and approaches to design and synthesize advanced battery materials. Outlook and perspectives on the future research to build better SIBs are also provided.

25 ENERGY STORAGE↗
DOE OSTI2018

Solid-State Lithium/Selenium–Sulfur Chemistry Enabled via a Robust Solid-Electrolyte Interphase

Lithium/selenium-sulfur batteries have recently received considerable attention due to their relatively high specific capacities and high electronic conductivity. Different from the traditional encapsulation strategy for suppressing the shuttle effect, an alternative approach to directly bypass polysulfide/polyselenide formation via rational solid-electrolyte interphase (SEI) design is demonstrated here. It is found that the robust SEI layer that in situ forms during charge/discharge via interplay between rational cathode design and optimal electrolytes could enable solid-state (de)lithiation chemistry for selenium-sulfur cathodes. Hence, Se-doped S 22.2 Se/Ketjenblack cathodes can attain a high reversible capacity with minimal shuttle effects during long-term and high rate cycling. Moreover, the underlying solid-state (de)lithiation mechanism, as evidenced by in situ 7 Li NMR and in operando synchrotron X-ray probes, further extends the optimal sulfur confinement pore size to large mesopores and even macropores that have been long considered as inferior sulfur or selenium host materials, which play a crucial role in developing high volumetric energy density batteries. It is expected that the findings in this study will ignite more efforts to tailor the compositional/structure characteristics of the SEI layers and the related ionic transport across the interface by electrode structure, electrolyte solvent, and electrolyte additive screening.

(de)lithiation chemistry↗
DOE OSTI2019

Rational Design of Graphene-Supported Single Atom Catalysts for Hydrogen Evolution Reaction

The proper choice of nonprecious transition metals as single atom catalysts (SACs) remains unclear for designing highly efficient electrocatalysts for hydrogen evolution reaction (HER). In this article, reported is an activity correlation with catalysts, electronic structure, in order to clarify the origin of reactivity for a series of transition metals supported on nitrogen-doped graphene as SACs for HER by a combination of density functional theory calculations and electrochemical measurements. Only few of the transition metals (e.g., Co, Cr, Fe, Rh, and V) as SACs show good catalytic activity toward HER as their Gibbs free energies are varied between the range of -0.20 to 0.30 eV but among which Co-SAC exhibits the highest electrochemical activity at 0.13 eV. Electronic structure studies show that the energy states of active valence d z 2 orbitals and their resulting antibonding state determine the catalytic activity for HER. The fact that the antibonding state orbital is neither completely empty nor fully filled in the case of Co-SAC is the main reason for its ideal hydrogen adsorption energy. Moreover, the electrochemical measurement shows that Co-SAC exhibits a superior hydrogen evolution activity over Ni-SAC and W-SAC, confirming the theoretical calculation. Lastly, this systematic study gives a fundamental understanding about the design of highly efficient SACs for HER.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Boosting Superior Lithium Storage Performance of Alloy-Based Anode Materials via Ultraconformal Sb Coating–Derived Favorable Solid-Electrolyte Interphase

Alloy materials such as Si and Ge are attractive as high-capacity anodes for rechargeable batteries, but such anodes undergo severe capacity degradation during discharge-charge processes. Compared to the over-emphasized efforts on the electrode structure design to mitigate the volume changes, understanding and engineering of the solid-electrolyte interphase (SEI) are significantly lacking. This work demonstrates that modifying the surface of alloy-based anode materials by building an ultraconformal layer of Sb can significantly enhance their structural and interfacial stability during cycling. Combined experimental and theoretical studies consistently reveal that the ultraconformal Sb layer is dynamically converted to Li 3 Sb during cycling, which can selectively adsorb and catalytically decompose electrolyte additives to form a robust, thin, and dense LiF-dominated SEI, and simultaneously restrain the decomposition of electrolyte solvents. Hence, the Sb-coated porous Ge electrode delivers much higher initial Coulombic efficiency of 85% and higher reversible capacity of 1046 mAh g -1 after 200 cycles at 500 mA g -1 , compared to only 72% and 170 mAh g -1 for bare porous Ge. The present finding has indicated that tailoring surface structures of electrode materials is an appealing approach to construct a robust SEI and achieve long-term cycling stability for alloy-based anode materials.

25 ENERGY STORAGE↗
DOE OSTI2020

Revisiting the Role of Conductivity and Polarity of Host Materials for Long-Life Lithium–Sulfur Battery

Despite their high theoretical energy density and low cost, lithium-sulfur batteries (LSBs) suffer from poor cycle life and low energy efficiency owing to the polysulfides shuttle and the electronic insulating nature of sulfur. Conductivity and polarity are two critical parameters for the search of optimal sulfur host materials. However, their role in immobilizing polysulfides and enhancing redox kinetics for long-life LSBs are not fully understood. In this work we have conducted an evaluation on the role of polarity over conductivity by using a polar but nonconductive platelet ordered mesoporous silica (pOMS) and its replica platelet ordered mesoporous carbon (pOMC), which is conductive but nonpolar. It is found that the polar pOMS/S cathode with a sulfur mass fraction of 80 wt% demonstrates outstanding long-term cycle stability for 2000 cycles even at a high current density of 2C. Furthermore, the pOMS/S cathode with a high sulfur loading of 6.5 mg cm -2 illustrates high areal and volumetric capacities with high capacity retention. Complementary physical and electrochemical probes clearly show that surface polarity and structure are more dominant factors for sulfur utilization efficiency and long-life, while the conductivity can be compensated by the conductive agent involved as a required electrode material during electrode preparation. The present findings shed new light on the design principles of sulfur hosts towards long-life and highly efficient LSBs.

25 ENERGY STORAGE↗
DOE OSTI2020

Understanding the Reactivity of a Thin Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 Solid–State Electrolyte toward Metallic Lithium Anode

The thickness of solid-state electrolytes (SSEs) significantly affects the energy density and safety performance of all-solid-state lithium batteries. However, a sufficient understanding of the reactivity toward lithium metal of ultrathin SSEs (<100 μm) based on NASICON remains lacking. Herein, for the first time, a self-standing and ultrathin (70 μm) NASICON-type Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 (LAGP) electrolyte via a scalable solution process is developed, and X-ray photoelectron spectroscopy reveals that changes in LAGP at the metastable Li-LAGP interface during battery operation is temperature dependent. Severe germanium reduction and decrease in LAGP particle size are detected at the Li-LAGP interface at elevated temperature. As a result, oriented plating of lithium metal on its preferred (110) face occurs during in situ X-ray diffraction cycling.

25 ENERGY STORAGE↗
DOE OSTI2021

Electrolytes Polymerization‐Induced Cathode‐Electrolyte‐Interphase for High Voltage Lithium‐Ion Batteries

Abstract Lithium‐ion batteries (LIBs) based on LiNi x Co y Mn 1‐x‐y O 2 (NCM) cathode materials have been widely commercialized, because of their high energy density, favorable rate performance, and relatively low cost. However, with increased Ni content to further increase their energy density, their cycling stability deteriorates dramatically and thus fails to meet the commercial application requirements. The artificial cathode‐electrolyte‐interphase (CEI) is a promising approach to solve this problem. Here, a robust CEI is fabricated through in situ polymerization of ethylene carbonate induced by aluminum isopropoxide (AIP). By adding 1 wt.% AIP in a commercial electrolyte, the capacity retention of LiNi 0.8 Co 0.1 Mn 0.1 O 2 ||Li cell at 1 C rate has been significantly increased from 80.8% to 97.8% with a highly reversible capacity of 176 mA h g −1 after 200 cycles. AIP can be also used as an additive during the slurry‐making process, enabling a reversible capacity of 170 mA h g −1 for LiCoO 2 after 200 cycles even at a high charge cut‐off voltage of 4.6 V. It is confirmed that the in situ formed CEI layer can prevent the cathodes from cracking and reduce the irreversible phase transformation.

Yang, Jixiang↗
DOE OSTI2021

High-Voltage and High-Safety Practical Lithium Batteries with Ethylene Carbonate-Free Electrolyte

Serious safety issues are impeding the widespread adoption of high-energy lithium-ion batteries for transportation electrification and large-scale grid storage. Herein, a triple-salt ethylene carbonate (EC) free electrolyte for high-safety and high-energy pouch-type LiNi 0.8 Mn 0.1 Co 0.1 O 2 |graphite (NMC811|Gr) cells is reported. This EC-free electrolyte can effectively stabilize the NMC811 surface under high potential (up to 4.5 V), as well as generate a stable interphase to achieve a superior compatibility with the Gr anode. The electrolyte strategy enables significantly enhanced intrinsic safety (trigger temperature of thermal runaway (TR) increased by 67.0 °C), excellent electrochemical properties (4.2V, ≈100% after 200 cycles), and superior high voltage stability (4.5 V, 82.1% after 200 cycles). Furthermore, the work opens up a new avenue for developing novel electrolyte systems to build safer high-energy batteries for practical applications.

25 ENERGY STORAGE↗
DOE OSTI2022

Nonradiative Recombination via Charge-Transfer-Exciton to Polaron Energy Transfer Limits Photocurrent in Organic Solar Cells

Here, a recombination and exciton loss mechanism is reported in organic solar cells involving energy transfer between charge transfer (CT) excitons and polarons, impacting photocurrent generation, particularly in the near-infrared where polaronic transitions typically reside. This process sets a low-energy cut-off in the external quantum efficiency spectrum of an excitonic donor/acceptor interface, determined by the low-energy polaron absorption peak and the CT state reorganization energy. Furthermore, this process explains the deviation from unity and bias dependence of the CT state's internal quantum efficiency at low photon energies. This process is demonstrated in a variety of systems and it is hypothesized that CT state to polaron energy transfer recombination may be responsible for a share of nonradiative recombination in all organic photovoltaics and can explain numerous experimentally observed device trends regarding photocurrent generation and energy losses. Overall, this work enhances the understanding of photophysical processes in organic materials and allows the design of systems that can avoid this recombination pathway.

14 SOLAR ENERGY↗
DOE OSTI2023

Dispersive Charge Transfer State Electroluminescence in Organic Solar Cells

Abstract The notion of quasi‐equilibrium is central to most solar cells; however, it has been questioned in organic photovoltaics (OPVs) owing to strong energetic disorder that frustrates efficient relaxation of electrons and holes within their respective density of states (DOS). Here, modulation electroluminescence (EL) spectroscopy is applied to OPVs and it is found that the frequency response of charge transfer (CT) state EL on the high energy side of the spectrum differs from that of the low energy side. This observation confirms that static disorder contributes substantially to the linewidth of the steady‐state EL spectrum and is unambiguous proof that the distribution of CT states formed by electrical injection in the dark is not in quasi‐equilibrium. These results emphasize the need for caution when analyzing OPV cells on the basis of reciprocity models that assume quasi‐equilibrium holds, and highlight a new method to study this unusual aspect of OPV operation.

14 SOLAR ENERGY↗
DOE OSTI2026

Manipulating Na/TM Ratio‐Driven Structural Heterogeneity of O3‐NaNi 1/3 Fe 1/3 Mn 1/3 O 2 Cathode for High‐Voltage Sodium‐Ion Batteries

The stability of O3-type NaNi 1/3 Fe 1/3 Mn 1/3 O 2 under high-voltage cycling is dictated by how synthesis encodes lattice strain and redox heterogeneity. Here, in this study, the role of Na:TM stoichiometry is systematically resolved by tuning the NaOH:precursor ratio during solid-state synthesis. The stoichiometric condition (Na:TM = 1.00) yields minimized microstrain, enabling uniform O3–P3 phase evolution and homogeneous multi-metal redox with preserved octahedral symmetry. In contrast, Na-excess compositions inherit disordered intermediates and heterogeneous distortion fields that trigger abrupt multiphase transitions and promote localized charge redistribution. In situ XRD captures the divergence in phase-transition pathways, TXM resolves particle-level redox heterogeneity, and XANES corroborates a stronger and more reversible Fe redox contribution at stoichiometry, shifting to diminished Fe participation and spatially inhomogeneous redox at higher Na content. These results establish Na:TM stoichiometry as a critical synthesis parameter controlling both structural coherence and redox stability. Electrochemically, the stoichiometric composition exhibits smooth voltage profiles with minimal polarization growth and retains nearly 80% of its initial capacity after 100 cycles even at an extended 4.2 V cutoff, whereas Na-excess compositions show significantly reduced initial coulombic efficiency and rapid voltage fade. Precise stoichiometric tuning provides a scalable route to defect-suppressed O3 frameworks, enabling structurally resilient, high-voltage sodium-layered cathodes.

36 MATERIALS SCIENCE↗