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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 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Electrochemo-mechanics unlocks hidden dynamics of lithium plating under stacking pressure

Understanding and mitigating lithium plating remains one of the most pressing challenges in advancing the safety and longevity of lithium-ion batteries (LIBs). Here, we present a novel integrative framework that combines in-operando swelling force measurements with a physics-based electro-chemo-mechanical model to uncover previously inaccessible insights into lithium plating dynamics under mechanical constraints. Unlike existing approaches that focus primarily on electrochemical signatures, our approach captures the coupled mechanical responses of commercial pouch cells during cycling, revealing how mechanical constraints fundamentally alter degradation pathways. We demonstrate that the use of a moderate stacking pressure suppresses lithium plating and enhances lithium stripping. This mechanically driven structural effect, coupled with the electrochemical process, significantly extends the linear aging regime in LIBs. Intriguingly, intermittent capacity recovery events that were observed during the battery cycling suggest dynamic lithium reactivation, a phenomenon rarely captured in real-time. This study pioneers a stress-aware methodology for diagnosing and managing lithium plating, establishing a new paradigm for real-time battery health monitoring. The findings offer transformative implications for the design of durable, high-performance LIB systems, opening new avenues for intelligent control strategies in battery management systems.

Bhowmick, Amit↗
DOE OSTI2025

Unveiling dark brown carbon: The hidden light-absorbing aerosols from biomass burning

The global rise in wildfire severity highlights the significant warming impact of brown carbon aerosols. Further, new findings reveal water-insoluble “dark brown carbon” tar balls that absorb far more light than the previously studied water-soluble brown carbon, representing a major unaccounted factor in global Earth System Models.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

FeSi 4 P 4 and CoSi 3 P 3 : Hidden Gems of Ternary Tetrel Pnictides with Outstanding Nonlinear Optical Properties

Metal silicon phosphides have shown promise as nonlinear optical materials. To be practically useful and cheap, earth-abundant 3d transition metals are preferred over their scarcer and more expensive 4d and 5d counterparts. Here, we developed a synthetic method to produce polycrystalline bulk powders and millimeter-sized single crystals of ternary compounds FeSi 4 P 4 and CoSi 3 P 3 . Both studied compounds have noncentrosymmetric and chiral crystal structures with ordered Si/P arrangements as was confirmed by single-crystal X-ray diffraction and solid-state NMR. Despite the presence of the transition metal, FeSi 4 P 4 and CoSi 3 P 3 are semiconductors with direct band gaps of 1.3 and 1.6 eV, respectively, indicating low-spin d 6 electronic configuration for octahedral Fe 2+ and Co 3+ . Relative to reported sulfide materials, FeSi 4 P 4 and CoSi 3 P 3 small band gap semiconductors demonstrate an outstanding combination of second-harmonic generation (SHG) activity and laser damage threshold (LDT). Both studied materials are phase-matchable with a 2.09 μm laser and not only exhibit 2.5–3.0 times stronger SHG signal than that of the state-of-the-art AgGaS 2 standard but also demonstrate an LDT response of 2.3–2.5 times higher than that of AgGaS 2 (at 1.09 μm laser with a pulse width of 10 ns)-which is unprecedented for small band gap semiconductors.

36 MATERIALS SCIENCE↗
DOE OSTI2026

The Hidden Path to the Resonance-Stabilized Fulvenallenyl Radical (C 7 H 5 ) via the Bimolecular Reaction of Tricarbon (C 3 , X 1 Σ g + ) with 1,3-Butadiene (C 4 H 6 ; X 1 A g )

Here, we report a novel bimolecular reaction pathway forming the resonance-stabilized fulvenallenyl radical (C 7 H 5 ) via the gas-phase reaction of tricarbon (C 3 , X 1 Σ g + ) with 1,3-butadiene (C 4 H 6 , X 1 A g ). Crossed molecular beam experiments combined with high-level electronic structures and statistical calculations reveal a rich potential energy surface. The reaction proceeds via tricarbon addition to a double bond of 1,3-butadiene, overcoming a 30 kJ mol –1 barrier, followed by ring closure, isomerizations (ring opening/closures, hydrogen shifts), and eventual hydrogen atom loss, yielding the fulvenallenyl radical (p1) almost exclusively via two dominant pathways. Considering the entrance barrier, this reaction may occur in high-temperature environments, like circumstellar envelopes of carbon stars, but is suppressed in colder regions such as molecular clouds and Titan’s atmosphere. These findings highlight the unexpected reactivity of small carbon clusters in shaping the molecular complexity of our universe, from the flicker of a flame to the death of a star.

Aromatic compounds↗
DOE OSTI2020

Hidden Subsurface Reconstruction and Its Atomic Origins in Layered Oxide Cathodes

Structural transformations near surfaces of solid-state materials underpin functional mechanisms of a broad range of applications including catalysis, memory, and energy storage. It has been a long-standing notion that the outmost free surfaces, accompanied by broken translational symmetry and altered atomic configurations, are usually the birthplace for structural transformations. Here, in a layered oxide cathode for Li-ion batteries, we for the first time observe the incipient state of the well documented layered-to-spinel-like structural transformation, which is surprisingly initiated from subsurface layer, rather than the very surface. Coupling atomic level scanning transmission electron microscopy imaging with electron energy loss spectroscopy, we discover that the reconstructed subsurfaces, featuring a mix of discrete patches of layered and spinel-like structures, are associated with selective atomic species partition and consequent nanoscale non-uniform composition gradient distribution at the subsurface. In conclusion, our findings provide fundamental insights on atomic-scale mechanisms of structural transformation in layered cathodes.

25 ENERGY STORAGE↗
DOE OSTI2021

Toward Decoding the Relationship between Domain Structure and Functionality in Ferroelectrics via Hidden Latent Variables

Polarization switching mechanisms in ferroelectric materials are fundamentally linked to local domain structure and the presence of the structural defects, which both can act as nucleation and pinning centers and create local electrostatic and mechanical depolarization fields affecting wall dynamics. However, the general correlative mechanisms between domain structure and polarization dynamics are only weakly explored, precluding insight into the associated physical mechanisms. In this work, the correlation between local domain structures and switching behavior in ferroelectric materials is explored using convolutional encoder–decoder networks, enabling image to spectral (im2spec) and spectral to image (spec2im) translations via encoding of latent variables. The latter reflect the assumption that the relationship between domain structure and polarization switching is parsimonious, i.e., is based upon a small number of local mechanisms. The analysis of latent variables distributions and their real-space representations provides insight into the predictability of the local switching behavior and hence associated physical mechanisms. We further pose that the regions where these correlative relationships are violated, i.e., predictability of the polarization dynamics from domain structure is reduced, represent the obvious target for detailed studies, e.g., in the context of automated experiments. This approach provides a workflow to establish the presence of correlation between local spectral responses and local structure and can be universally applied to spectral imaging techniques such as piezoresponse force microscopy (PFM), scanning tunneling microscopy (STM) and spectroscopy, and electron energy loss spectroscopy (EELS) in scanning transmission electron microscopy (STEM).

36 MATERIALS SCIENCE↗