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All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Natural isotopic compositions of titanium, iron, and nickel observed in commercial fuel pellets – Promising candidate elements for stable isotope tagging

Stable isotope taggants would constitute unique identifiers for nuclear fuel cycle materials, resulting in expedited timelines and high confidence provenance assessments for nuclear forensics investigations. However, reliably identifying and interpreting stable isotope taggants in nuclear materials recovered from outside of regulatory control will largely be predicated on the assumption that the taggant element intrinsic to the untagged nuclear material exhibits natural isotopic ratios. Here, we present high-precision Ti, Fe, and Ni isotope compositions in 13 commercial low-enriched uranium (LEU) fuel pellets to assess the suitability of these transition metals as stable isotope taggants. Our investigations reveal limited isotope variations among the fuel pellets in all three elements, which are consistent with small mass-dependent isotope fractionations, comparable to variations previously reported for natural samples. In practice, isotopically tagged nuclear materials are expected to fall along isotopic mixing lines, since intrinsic background levels of taggant elements dilute the taggant towards natural isotope compositions. Furthermore, the observation that Ti, Fe, and Ni isotope compositions in a suite of LEU fuel pellets are close to or indistinguishable from estimates for the Bulk Silicate Earth demonstrates that a two end-member mixing assumption would be valid for these transition metals, indicating that all three are promising candidate elements for stable isotope tagging. Finally, we present mass balance calculations to quantify isotopic perturbations expected from admixing isotopically anomalous Ti, Fe, and Ni taggants to assess the interplay between elemental and taggant concentrations and find favorable compromises for facilitating successful taggant identification with current analytical methods.

Intentional forensics↗
DOE OSTI2026

Uncertainty quantification for competing failure mechanisms in unidirectionally reinforced carbon–carbon composites

Microstructure-informed finite element models play a key role in the carbon–carbon composite design process. Variability in manufacturing process parameters and experimental limitations introduce model parameter uncertainty. This study quantifies the effect of model parameter uncertainty on transverse tensile fracture behavior and proposes a methodology to predict the failure mode based on competing microscale damage mechanisms. Finite element simulations incorporate fiber–matrix interface debonding with cohesive zones and matrix damage with a smeared crack band approach in a unidirectional carbon–carbon composite. Results from a variance-based global sensitivity analysis identifies interfacial and matrix damage parameters as the primary source of variability in fracture behavior. Sobol’ indices indicate that matrix and cohesive zone strengths contribute 94% of the variance in the effective ultimate stress. A local analysis elucidates the relationship between these constituent strength parameters and failure mode by estimating the probability of cohesive, matrix, and mixed-mode dominated failure. Based on the results for 4000 simulations, 93% exhibit mixed-mode or interfacial dominated failure, which underscores the crucial role of fiber–matrix interface debonding in the transverse tensile failure of carbon–carbon composites. These uncertainty quantification results facilitate more efficient model calibration and provide a framework for microstructure-informed failure predictions in the face of manufacturing-induced uncertainty.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Compositionally graded aluminum-silicon alloy fabricated via friction extrusion

Herein, a novel solid-phase gradient alloying technique was developed for a high throughput composition-microstructure-mechanical property assessment. Friction extrusion of a two-piece billet setup facilitated the formation of a seamless compositionally graded aluminum (Al)-silicon (Si) extrudate rod, with Si concentration in Al matrix gradually increasing from ~1 at% at one end to ~7 at% at the other end of the rod. We observed a strong dependence of the Al grain size, morphology, and texture on the Si concentration. The Si particles pinned the recrystallized grain boundaries resulting in refined (< 10 µm) and textured grains in the high Si content region, while the Al grains in the low Si region are equiaxed, randomly textured, and with a larger average size (~50 µm). The hardness of Al-Si gradient extrudate increases by ~50% percent with a 6 at% increase in Si content due to Hall Petch and particle strengthening effects. Our approach demonstrates the use of a solid phase processing technique to successfully produce a defect-free continuously compositionally graded bulk components thus overcoming the limitations of porosity and material heterogeneities commonly observed in other techniques such as by additive laser deposition.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Wood template-supported phase change material composites for durable and form-stable thermal energy storage in buildings

Here, to reduce and shift peak energy loads in buildings, phase change materials (PCMs) with high transition enthalpies and transition temperatures near human thermal comfort are desirable for thermal energy storage (TES). Traditional solid/liquid PCMs suffer from leakage during thermal cycling, requiring encapsulation that lowers heat storage capacity. Wood templates (WTs), with porous and hierarchical structures, provide natural encapsulation scaffolds for PCM containment. Polyethylene glycol (PEG) is a compatible PCM with WTs, but when infiltrated alone, ~30 wt% of PEG binds to wood with no detectable phase change, limiting TES efficiency. To address this, we developed a method to (1) improve the form stability of balsa and pine-based composites (BWT + PCMs and PWT + PCMs) and (2) reduce inactive PCM within the composites to ~10 wt%. BWT + PCMs exhibit transition properties upwards of 114.2 J/g at 25.4 degrees C, with no degradation after 1000 thermal cycles, and similar stiffness compared to raw balsa. Meanwhile, PWT + PCMs exhibit 25 % higher storage efficiency with the addition of poly(ethylene glycol) diacrylate compared to solely PEG-infiltrated PWT. PWT + PCM retains 84 % of raw pine's mechanical stiffness, sufficient for light-duty construction. Our shape-stabilized WT + PCM composites enrich the functionality of wood materials as both ideal TES material candidates and light-duty building construction applications.

25 ENERGY STORAGE↗
DOE OSTI2023

Low temperature hydrogen superpermeation in vanadium composite metal foil pumps

Palladium-based foil membranes are an effective option for hydrogen isotope recovery from the plasma exhaust of future fusion plants, but cost and availability are concerns. Vanadium (V) is a relatively low cost, neutron tolerant material with high hydrogen permeability. It has been well-studied as a superpermeable membrane at high temperature (>500 °C), but V displays negligible superpermeation at low temperature (75–200 °C) due to catalytic limitations. Composite membranes were fabricated by depositing thin layers (~100 nm) of either Pd or BCC PdCu on sputter-cleaned vanadium foils (100 μm). Symmetric membranes elevated superpermeation to levels approaching bulk Pd or PdCu foils, with ~5X higher flux in the latter reflecting the superior properties of PdCu. Asymmetric membranes revealed that the Pd-based catalyst layer was critical for both efficient absorption of superthermal hydrogen upstream as well as catalyzing re-combinative desorption downstream. At T ≥ 150 °C composite membrane superpermeation was equivalent to the Pd-based foils, but the flux was attenuated by a factor of 2-3X as the temperature was reduced. This deviation from pure foil performance coincided with the formation of vanadium hydride (β-V 2 H), which also impacted the transient response. Nevertheless, no embrittlement was observed under the conditions examined and elevating the temperature >150 °C removed the hydride and restored full performance. The achievement of palladium-level performance with a >99% reduction in Pd inventory makes these V composite metal foils pumps an attractive option for low temperature hydrogen isotope recovery in future fusion plants.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2023

Design of a novel carbon/carbon composite microvascular solar receiver

Solar thermal power tower systems are the primary technology being proposed for solar electricity from thermal energy. Operational limits on these towers are often driven by mechanical properties under significant thermal loads, particularly at the receiver where incoming flux is converted to thermal energy. While the solar receiver’s efficiency is largely driven by its optical properties, thermomechanical stresses on the receiver limits the operational envelope. One pathway to higher efficiency is greater allowable solar fluxes on the receiver but novel materials are required. The present study uses computational fluid dynamics to describe a parametric design space for a microvascular carbon/carbon composite solar receiver as a new material option for high flux solar receivers. Simulations are conducted for different microvascular geometries considering the role of material properties and heat transfer fluids, for the impact on thermal efficiency, and allowable strain. Results show that microscale receiver modules made of the proposed carbon/carbon composite could achieve thermal efficiencies over 90% and full-scale receivers can achieve up to 85% thermal efficiency for the design explored considering realistic strain limits, flux levels, and material properties. These values are highly dependent on the heat transfer fluid pairing, the through plane thermal conductivity of the carbon/carbon composite, the path architecture of the microscale receiver, and the incident solar flux profiles.

14 SOLAR ENERGY↗
DOE OSTI2025

Critical role of polymer-ceramic ion exchange for high conductivity composite electrolytes

Polymer-ceramic composites offer a path to enhance the transport and mechanical properties of solid electrolytes. However, an in-depth understanding of the extent and role of ion transport along and across polymer-ceramic interfaces in these systems is lacking. We have recently shown that Li-conducting Li 0.11 Na 0.24 K 0.02 La 0.43 TiO 2.82 (LMTO) nanorods can be prepared by a molten flux method, and the addition of 30–50 weight (wt.)% LMTO to a bis[(trifluoromethyl)sulfonyl]imide-vinyl ethylene carbonate-based single-ion conducting (SIC) polymer electrolyte leads to a two-fold enhancement in Li-ion conductivity, from 1.4 to 3.0 × 10 −5 S/cm at 30 °C. In the present study, we use NMR methods to identify the Li-ion transport pathways and determine the timescale of chemical exchange between the SIC polymer and LMTO ceramic components. Tracer exchange NMR indicates preferential transport through the polymer or polymer-interfacial regions, and exchange spectroscopy (EXSY) and a new isotope exchange method reveal negligible Li exchange between the SIC polymer and LMTO ceramic up to several days. Here, LMTO nanorods act as a passive filler. Our results further highlight that significant (e.g., 10- or 100-fold) conductivity enhancements in composite electrolytes can only be achieved 1) with ionically-conductive fillers, and 2) when both the ceramic and polymer components actively participate in long-range transport. For this, fast interfacial ion exchange is needed. In conclusion, this leads us to introduce a critical interfacial ion exchange time to evaluate whether a filler actively contributes to conduction in a composite electrolyte, and screen for promising polymer-ceramic pairings to accelerate the development of high conductivity solid electrolytes.

Battery, Solid electrolyte↗
DOE OSTI2026

While legume-based rotation influences the chemical composition of mineral-associated organic matter, tillage has little effect on its persistence

Legume-based rotations are key to enhancing soil carbon (C) storage in stable forms such as mineral-associated organic matter (MAOM), improving soil health, and helping maintain long-term C stock. This study investigates how plant inputs and tillage practices influence the distribution, composition, and persistence of MAOM in wheat cropping systems when legumes are incorporated into the rotation. Soil samples were collected from Walla Walla silty loam of northeast Oregon, including conventional tillage (CT) and no-till (NT) treatments in a long-term dryland winter wheat (Triticum aestivum L.) and spring pea (Pisum sativum L.) rotation experiment, with an adjacent grass pasture (GP) plot serving as the baseline. Bulk soil, particulate organic matter (POM), and MAOM fractions were scanned using mid-infrared (Mid-IR) spectroscopy and analyzed for total C and nitrogen (N) as well as radiocarbon age, aggregate stability, and mineralizable C. In WP systems, NT promoted greater C accumulation and stabilization in MAOM than CT, reaching levels similar to those under native GP conditions. Furthermore, our findings indicate that decades of continuous legume-based rotation were insufficient to restore total bulk C content to levels observed in the undisturbed reference site (GP) in the 0–30 cm layer, with increases limited to the surface layer. The Mid-IR data provided insights into how cultivation may alter the chemical composition of MAOM. An increase in amide bands was observed in GP, while legume-based rotation systems favored an abundance of aliphatic (C-H) components in the MAOM fraction. In cultivated soils, C in MAOM exhibited longer residence times under arable conditions than in grassland, while POM remained an actively cycled pool across all treatments. Despite variations in the chemical composition of MAOM across treatments, mineralizable C emissions from MAOM fractions remained statistically unchanged during the 96-hour incubation period. Our findings suggest that soil physical protection, enhanced by reduced tillage, is the primary factor influencing MAOM cycling.

Carbon stabilization↗
DOE OSTI2023

Strain-Mediated Sn Incorporation and Segregation in Compositionally Graded Ge 1– x Sn x Epilayers Grown by MBE at Different Temperatures

We investigated the process of Sn incorporation and surface segregation for compositionally graded Ge 1–x Sn x epilayers grown on high-quality Ge (001) substrates. Here, the growth resulted in pseudomorphic GeSn layers with a ~6% maximal Sn fraction at a constant substrate temperature. The maximal fraction of Sn was increased to 9.0% when the growth temperature was continuously lowered while increasing the Sn flux. The analysis of surface droplets and SIMS profiles of elemental composition give evidence of Sn rejection during the growth, potentially associated with a critical energy of elastic strain. The intentional reduction of the coherent strain by decreasing the Sn flux near the sample surface has been shown to trap a higher fraction of Sn in the Ge 1–x Sn x layer and lower surface segregation. Our results demonstrate that strain relief by misfit dislocations in the compositionally graded layer is inhibited, which leads to Sn segregation. Specifically, the compressive strain in the graded Ge 1–x Sn x epilayer is effectively “zero” near the interface with the Ge substrate and increases up to about –1.5 × 10 –2 near the surface. Thus, although the nucleation of a dislocation may reduce the compressive strain for the top region of the epilayer, it is not beneficial for the bottom region.

42 ENGINEERING↗
DOE OSTI2020

Nitride or Oxynitride? Elucidating the Composition–Activity Relationships in Molybdenum Nitride Electrocatalysts for the Oxygen Reduction Reaction

Molybdenum nitride (Mo–N) catalysts have shown promising activity and stability for the oxygen reduction reaction (ORR) in acid. However, the effect of oxygen (O) incorporation (from synthesis, catalysis, or exposure to air) on their activity remains elusive. Here, we use reactive sputtering to synthesize three compositions of thin-film catalysts and use extensive materials characterization to investigate the depth-dependent structure and incorporated O. We show that the as-deposited Mo–N films are highly oxidized both at the surface (>30% O) and in the bulk (3–21% O) and that the ORR performance is strongly correlated with the bulk structure and composition. Activity for 4e– ORR is highest for compositions with the highest N/O and N/Mo ratio. Furthermore, H 2 O 2 production for the films with moderate O content is comparable to or higher than the most H 2 O 2 -selective nonprecious metal catalysts in acidic electrolyte, on a moles per mass or surface area of catalyst basis. Density functional theory provides insight into the energetics of O incorporation and vacancy formation, and we hypothesize that activity trends with O/N ratios can be traced to the varying crystallite phases and their interactions with ORR adsorbates. This work demonstrates the prevalence and significance of O in metal nitride electrocatalysts and motivates further investigation into the role of O in other nonprecious metal materials.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Chemical Signatures of Seasonally Unique Anthropogenic Influences on Organic Aerosol Composition in the Central Amazon

Urbanization and fires perturb the quantities and composition of fine organic aerosol in the central Amazon, with ramifications for radiative forcing and public health. These disturbances include not only direct emissions of particulates and secondary organic aerosol (SOA) precursors, but also changes in the pathways through which biogenic precursors form SOA. The composition of ambient organic aerosol is complex and incompletely characterized, encompassing millions of potential structures relatively few of which have been synthesized and characterized. Through analysis of submicron aerosol samples from the Green Ocean Amazon (GoAmazon2014/5) field campaign by two-dimensional gas chromatography coupled with machine learning, ~1300 unique compounds were traced and characterized over two seasons. Fires and urban emissions produced chemically and interseasonally distinct impacts on product signatures, with only ~50% of compounds observed in both seasons. Seasonally unique populations point to the importance of aqueous processing in Amazonian aerosol ageing, but further mechanistic insights are impeded by limited product identity knowledge. Further, less than 10% of compounds were identifiable at an isomer-specific level. Overall, the findings (i) provide compositional characterization of anthropogenic influence on submicron organic aerosol in the Amazon, (ii) identify key season-to-season differences in chemical signatures, and (iii) highlight high-priority knowledge gaps in current speciated knowledge.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

PDG: A Composite Method Based on the Resolution of the Identity

The Gaussian-3 (G3) composite approach for thermochemical properties is revisited in light of the enhanced computational efficiency and reduced memory costs by applying the resolution-of-the-identity (RI) approximation for two-electron repulsion integrals (ERIs) to the computationally demanding component methods in the G3 model: the energy and gradient computations via the second-order Møller–Plesset perturbation theory (MP2) and the energy computations using the coupled-cluster singles–doubles method augmented with noniterative triples corrections [CCSD(T)]. Efficient implementation of the RI-based methods is achieved by employing a hybrid distributed/shared memory model based on MPI and OpenMP. The new variant of the G3 composite approach based on the RI approximation is termed the RI-G3 scheme, or alternatively the PDG method. The accuracy of the new RI-G3/PDG scheme is compared to the “standard” G3 composite approach that employs the memory-expensive four-center ERIs in the MP2 and CCSD(T) calculations. Taking the computation of the heats of formation of the closed-shell molecules in the G3/99 test set as a test case, it is demonstrated that the RI approximation introduces negligible changes to the mean absolute errors relative to the standard G3 model (less than 0.1 kcal/mol), while the standard deviations remain unaltered. Furthermore, the efficiency and memory requirements for the RI-MP2 and RI-CCSD(T) methods are compared to the standard MP2 and CCSD(T) approaches, respectively. The hybrid MPI/OpenMP-based RI-MP2 energy plus gradient computation is found to attain a 7.5× speedup over the standard MP2 calculations. For the most demanding CCSD(T) calculations, the application of the RI approximation is found to nearly halve the memory demand, confer about a 4–5× speedup for the CCSD iterations, and reduce the computational time for the compute-intensive triples correction step by several hours.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Composition and Configuration Dependence of Glass-Transition Temperature in Binary Copolymers and Blends of Polyhydroxyalkanoate Biopolymers

Polyhydroxyalkanoates (PHAs), a promising class of biomaterials, have gained considerable attention to replace petroleum-based plastics owing to their excellent biocompatibility and biodegradability. Homopolymers of PHA suffer from poor tunability in thermal and mechanical properties. Going from homopolymers to copolymers, the design space can be substantially enhanced by combining two or more monomers in different compositions (i.e., relative ratios of the different monomers) and configurations (i.e., relative positions of the different monomers in the polymer backbone) leading to a substantially large chemical space where application-specific optimization for the targeted functionality can be performed. However, this composition and configuration dependence of properties in the vast PHA copolymer chemical space remains largely unexplored. In this contribution, further building on our past work with PHA homopolymers, we systematically explore these chemical trends for glass-transition temperature (Tg) in PHA copolymers and blends. Overall, our molecular dynamics simulations, utilizing a previously validated force field for PHAs, suggest that these trends are largely governed not only by the homopolymer Tg values but also configuration-dependent interchain interactions in the copolymer system. In particular, our results indicate that the configuration-dependent variation in the target property at a fixed composition can be significant in the presence of hydrogen-bond-forming monomers. These qualitative observations are further rationalized by quantitatively analyzing various closely related atomic level descriptors of copolymers and blends such as monomer mobility, number of hydrogen bonds, and pair correlation functions. The findings presented in this work help to develop a deeper atomistic-level understanding of thermomechanical behavior of PHA-based copolymers and can potentially guide the rational design of biopolymers as environmental-friendly functional materials.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Cobalt Metal–Cobalt Carbide Composite Microspheres for Water Reduction Electrocatalysis

Microspheres of cobalt metal–cobalt carbide (Co–Co x C, Co x C: Co 2 C and Co 3 C) composite with carbon shells were prepared via an OH – - and Cl – -assisted polyol method and explored for electrocatalytic activity and stability for the hydrogen evolution reaction (HER) in acidic media. From our transmission electron microscopy observations, the outermost surfaces of the as-prepared Co–Co x C composites were primarily covered with Co 2 C crystallites. Our best performing electrocatalyst exhibited superior HER activity with an overpotential of 78 mV to reach a current density of -10 mA·cm –2 , a Tafel slope of 87.8 mV·dec –1 , and 1 h of electrode durability. We show that this excellent HER performance is primarily due to the superior intrinsic activity of Co 2 C, as well as the high electrical conductivity resulting from the inclusion of cobalt metal and the presence of graphitic carbon shells in and on the composite, respectively. Using both computational and experimental approaches, we determine here that the carbon-rich cobalt carbide (Co 2 C) phase is more favorable for the HER than the carbon-poor phase (Co 3 C).

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Irreversible Multielement Diffusion and the Resulting Compositional and Processing Flexibility in the Synthesis and Densification of Lithium Aluminum Lanthanum Zirconium Oxide

Despite the broad interest in Al-doped lithium lanthanum zirconium oxide (LLZO), the wide range of reported ionic conductivities suggests that the effect of processing parameters on the resulting phase purity and bulk conductivity is not well-understood. Here, in this work, we synthesized six separate series of LLZO with variations in Al concentration, Li excess, Li addition order, Li source, densification method, and mother powder to determine the effect on the composition, phase purity, density, and bulk conductivity. We found that a wider range of compositions (6.08–7.61 mol of Li and 0.06–0.23 mol of Al) than previously reported can result in cubic phase stability and that nearly all elements (Li, Al, Zr, and La) are lost to the MgO crucible during calcination and sintering. The manner in which different elements are lost is affected by the processing parameters. We observed that Al-doped LLZO shows great compositional flexibility in stabilizing the cubic phase, offering an explanation for the range of electrochemical performance metrics reported in the literature.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Design of Graphene/Ionic Liquid Composites for Carbon Capture

Pore size is a crucial factor impacting gas separation in porous separation materials, but how to control the pore size to optimize the separation performance remains a challenge. Here, we propose a design of graphene/ionic liquid composites with tunable slit pore sizes, where cations and anions of ionic liquids are intercalated between graphene layers. By varying the sizes of the ions, we show from first-principles density functional theory calculations that the accessible pore size can be tuned from 3.4 to 6.0 Å. Grand canonical Monte Carlo simulations of gas sorption find that the composite materials possess high CO 2 uptake at room temperature and 1 bar (up to ~8.5 mmol/g). Further simulations of the sorption of gas mixtures reveal that high CO 2 /N 2 and CO 2 /CH 4 adsorption selectivities can be obtained when the accessible pore size is <5 Å. This work suggests a new strategy to achieve tunable pore sizes via the graphene/IL composites for highly selective CO 2 /N 2 and CO 2 /CH 4 adsorption.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Understanding the Effect of Cathode Composition on the Interface and Crosstalk in NMC/Si Full Cells

Crosstalk between the cathode and the anode in lithium-ion batteries has a great impact on performance, safety, and cycle lifetime. Still, no report exists for a systematic investigation on crosstalk behavior in silicon (Si)-based cells as a function of transition metal composition in cathodes. We studied the effect of crosstalk on degradation of Si-rich anodes in full cells with different cathodes having the same crystal structure but different transition metal compositions, such as LiNi 1/3 Mn 1/3 Co 1/3 O 2 (NM111), LiNi 0.5 Mn 0.3 Co 0.2 O 2 (NMC532), and LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811). We found that the transition metal composition in cathodes, especially Mn ion concentration, significantly affects electrolyte decomposition reactions, even from very early cycles. This change causes differences in the solid electrolyte interphase (SEI) chemistry of each aged Si sample. As a result, each of the aged Si samples has a different electrochemistry, in terms of initial Coulombic efficiency and the mechanism of capacity fade.

25 ENERGY STORAGE↗
DOE OSTI2024

Copper–Carbon Nanotube Composites Enabled by Brush Coating for Advanced Conductors

There is a growing demand for advanced conductors with enhanced electrical properties to increase the energy efficiency in various applications. A promising strategy to achieve this involves the use of ultraconductive copper (UCC) composites that incorporate highly conductive carbon materials, such as carbon nanotubes (CNTs), into the copper matrix. In this study, we present a scalable brush coating technique to incorporate CNTs onto Cu substrates to produce Cu–CNT–Cu composites. The process involves brush coating the CNT solution on Cu tape substrates, followed by vacuum-assisted thermal removal of organic moieties (e.g., surfactant/polymer). This step ensures the creation of a uniformly distributed CNT network within the Cu matrix. By addition of a thin film Cu overlayer, the fabricated Cu–CNT–Cu composite architecture demonstrates similar electrical conductivity, increased current carrying capacity, and enhanced mechanical properties compared to pure Cu reference tapes. Finally, the performance characteristics of these UCC tapes along with the scalability of the brush coating approach hold great promise for the fabrication of advanced conductors for wide-ranging energy applications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗