Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “durable”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 847 records · Page 47
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

Realization of Non‐Equilibrium Wurtzite Structure in Heterovalent Ternary MgSiN 2 Film Grown by Reactive Sputtering

The piezoelectric and ferroelectric applications of heterovalent ternary materials are not well explored. Epitaxial MgSiN 2 films are grown at 600 °C on (111)Pt//(001)Al 2 O 3 substrates by the reactive sputtering method using metallic Mg and Si under the N 2 atmosphere. Detailed X-ray diffraction measurements and transmission electron microscopy observations revealed that the epitaxially grown films on the substrates have a hexagonal wurtzite structure with c-axis out-of-plane orientation. The random occupation of this structure by Mg and Si differs from that of the previously reported structure in which these two cations periodically occupy the cationic sites. However, the lattice spacings closely approximate those that are previously reported, irrespective of the ordering, and they are almost comparable with those of (Al 0.8 Sc 0.2 )N. The wide bandgap of >5.0 eV in deposited MgSiN 2 is compatible with that of AlN and suggests durability against the application of strong external electric fields, possibly to induce polarization switching. In addition, MgSiN 2 is shown to have piezoelectric properties with an effective d 33 value of 2.3 pm V −1 for the first time. This work demonstrates the compositional expansion of hexagonal wurtzite to heterovalent ternary nitrides for novel piezoelectric materials, whose ferroelectricity is expected.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Achieving High‐Performance and 2000 h Stability in Anion Exchange Membrane Fuel Cells by Manipulating Ionomer Properties and Electrode Optimization

The primary function of the ionomers that are incorporated into fuel cell electrode catalyst layers is to provide pathways for ion transport between the catalyst active sites and the electrolyte. This is influenced by many variables, including the ion-exchange capacity, water uptake, and molecular weight. In anion exchange membrane fuel cells (AEMFCs), controlling ionomer water uptake is particularly important and tailoring this property in each electrode is an important consideration when looking to maximize cell performance. In this study, three poly(norbornene) tetrablock copolymer ionomers with a range of physical properties are synthesized and incorporated into AEMFC anode and cathode electrodes. Systematic electrode engineering with these ionomers allows the peak power density to be increased by 100% (1.6 W cm -2 → 3.2 W cm -2 ) and the current density at 0.2 V to be increased by 59% (5.9 A cm -2 → 9.4 A cm -2 ). Moreover, the top-performing electrode configuration is tested in an operating AEMFC at the US Department of Energy defined current density of 600 mA cm -2 for 2000 h, showing a record-low voltage decay rate of 15.36 µV h -1 – only 3.65% –a over 2000 h. Here, this work sets a new bar for AEMFCs, reporting the best combination of performance and durability of any AEMFC to date.

08 HYDROGEN↗
DOE OSTI2020

Porous FeCo Glassy Alloy as Bifunctional Support for High-Performance Zn-Air Battery

Zn-air battery (ZAB) is attracting increasing attention due to its high safety and performance. However, the practical application of ZAB relies heavily on developing durable support materials to replace conventional carbon supports which have unrecoverable corrosion issues, severely jeopardizing ZAB performance. Herein, a novel porous FeCo glassy alloy was developed as bifunctional catalytic support for ZAB. Specifically, the conducting skeleton of the porous glassy alloy was used to stabilize oxygen reduction cocatalysts, and more importantly, the FeCo served as the primary phase for oxygen evolution. To prove the concept of catalytic glassy alloy support, ultra-small Pd nanoparticles were anchored, as oxygen reduction active sites, on the porous FeCo (noted as Pd/FeCo) for ZAB. The Pd/FeCo exhibited a significantly improved electrocatalytic activity for oxygen reduction (a half-wave potential of 0.85 V) and oxygen evolution (a potential of 1.55 V to reach 10 mA cm –2 ) in the alkaline media. When used in the ZAB, the Pd/FeCo delivered an output power density of 117 mW cm –2 and outstanding cycling stability for over 200 h (400 cycles), surpassing the conventional carbon-supported Pt/C+IrO 2 catalysts. Such an integrated design of combining highly active components with porous architecture provides a new strategy to develop novel nanostructured electrocatalysts.

36 MATERIALS SCIENCE↗
DOE OSTI2020

High-Entropy Metal Sulfide Nanoparticles Promise High-Performance Oxygen Evolution Reaction

Transition metal sulfide with a multi-elemental nature represents a class of promising catalysts for oxygen evolution reaction (OER) owing to its good catalytic activity. However, its synthesis remains a grand challenge due to the thermodynamic immiscibility of the constituent multimetallic elements in a sulfide structure. Herein, we for the first time report a high-entropy metal sulfide (HEMS, i.e., (CrMnFeCoNi)Sx) solid solution nanoparticles. Computational and X-ray photoelectron spectroscopy analysis suggest that the (CrMnFeCoNi)S x exhibits a synergistic effect among metal atoms that leads to desired electronic states to enhance OER activity. The (CrMnFeCoNi)Sx nanoparticles showed one of the best activities (low overpotential 295 mV at 100 mA cm -2 in 1 M KOH solution) and good durability (only slight polarization after 10 hours by chronopotentiometry) compared with the unary, binary, ternary, and quaternary sulfide counterparts. This work opens up a new synthesis paradigm for high-entropy compound nanoparticles for highly efficient electrocatalysis applications.

25 ENERGY STORAGE↗
DOE OSTI2022

Oxide‐Based Solid‐State Batteries: A Perspective on Composite Cathode Architecture

Abstract The garnet‐type phase Li 7 La 3 Zr 2 O 12 (LLZO) attracts significant attention as an oxide solid electrolyte to enable safe and robust solid‐state batteries (SSBs) with potentially high energy density. However, while significant progress has been made in demonstrating compatibility with Li metal, integrating LLZO into composite cathodes remains a challenge. The current perspective focuses on the critical issues that need to be addressed to achieve the ultimate goal of an all‐solid‐state LLZO‐based battery that delivers safety, durability, and pack‐level performance characteristics that are unobtainable with state‐of‐the‐art Li‐ion batteries. This perspective complements existing reviews of solid/solid interfaces with more emphasis on understanding numerous homo‐ and heteroionic interfaces in a pure oxide‐based SSB and the various phenomena that accompany the evolution of the chemical, electrochemical, structural, morphological, and mechanical properties of those interfaces during processing and operation. Finally, the insights gained from a comprehensive literature survey of LLZO–cathode interfaces are used to guide efforts for the development of LLZO‐based SSBs.

25 ENERGY STORAGE↗
DOE OSTI2022

Carbon-Nanotube-Bridging Strategy for Integrating Single Fe Atoms and NiCo Nanoparticles in a Bifunctional Oxygen Electrocatalyst toward High-Efficiency and Long-Life Rechargeable Zinc–Air Batteries

The development of highly efficient and robust bifunctional electrocatalysts for oxygen reduction (ORR) and evolution reactions (OER) is the key issue for realizing high-performance and long-life rechargeable zinc–air batteries (ZABs). However, it is still a great challenge to integrate independent ORR and OER sites in a catalyst with high activity. Here, a carbon nanotube-bridging strategy is proposed to synthesize such a bifunctional oxygen electrocatalyst enriched with highly active single-atom Fe sites for the ORR and high-performance nanosized NiCo hydroxides for the OER. Consequently, the developed catalyst shows a small overpotential difference of 0.686 V. When used as an oxygen electrode catalyst, the corresponding ZAB exhibits a large power density of 219.5 mW cm ₋2 , a small charge–discharge voltage gap of 0.72 V at 10 mA cm ₋2 , and outstanding discharge–charge durability without attenuation after more than 700 cycles. This work proposes a new idea to realize multifunctional catalysts and drives the practical application of ZABs.

25 ENERGY STORAGE↗
DOE OSTI2023

Evaluation of Hybrid Perovskite Prototypes After 10-Month Space Flight on the International Space Station

Metal halide perovskites (MHPs) have emerged as a prominent new photovoltaic material combining a very competitive power conversion efficiency that rivals crystalline silicon with the added benefits of tunable properties for multijunction devices fabricated from solution which can yield high specific power. Perovskites have also demonstrated some of the lowest temperature coefficients and highest defect tolerance, which make them excellent candidates for aerospace applications. However, MHPs must demonstrate durability in space which presents different challenges than terrestrial operating environments. To decisively test the viability of perovskites being used in space, a perovskite thin film is positioned in low earth orbit for 10 months on the International Space Station, which was the first long-duration study of an MHP in space. Postflight high-resolution ultrafast spectroscopic characterization and comparison with control samples reveal that the flight sample exhibits superior photo-stability, no irreversible radiation damage, and a suppressed structural phase transition temperature by nearly 65 K, broadening the photovoltaic operational range. Further, significant photo-annealing of surface defects is shown following prolonged light-soaking postflight. Here these results emphasize that methylammonium lead iodide can be packaged adequately for space missions, affirming that space stressors can be managed as theorized.

14 SOLAR ENERGY↗
DOE OSTI2024

Platinum/Tantalum Carbide Core–Shell Nanoparticles with Sub‐Monolayer Shells for Methanol and Oxygen Electrocatalysis

Abstract Core–shell architectures provide great opportunities to improve catalytic activity, but achieving nanoparticle stability under electrochemical cycling remains challenging. Herein, core–shell nanoparticles comprising atomically thin Pt shells over earth‐abundant TaC cores are synthesized and used as highly durable electrocatalysts for the methanol oxidation reaction (MOR) and the oxygen reduction reaction (ORR) needed to drive direct methanol fuel cells (DMFCs). Characterization data show that a thin oxidic passivation layer protects the TaC core from undergoing dissolution in the fuel cell‐relevant potential range, enabling the use of partially covered Pt/TaC core–shell nanoparticles for MOR and ORR with high stability and enhanced catalytic performance. Specifically, at the anode the surface‐oxidized TaC further enhances MOR activity compared to conventional Pt nanoparticles. At the cathode, the Pt/TaC catalyst feature increases tolerance to methanol crossover. These results show unique synergistic advantages of the core–shell particles and open opportunities to tailor catalytic properties for electrocatalytic reactions.

Chemistry↗
DOE OSTI2025

Fine‐Tuning Li‐Ion Solvation Structure by Enhanced Solvent‐Diluent Interactions for Long‐Cycling Lithium Metal Batteries

Achieving durable lithium (Li) metal anodes in liquid electrolytes remains challenging, primarily due to the instability of the formed solid-electrolyte interphases (SEIs). Modulating the Li-ion solvation structures is pivotal in forming a stable SEI for stabilizing Li metal anodes. Here a strategy is developed to fine-tune the Li-ion solvation structures through enhanced dipole–dipole interactions between the Li-ion-coordinated solvent and the non-Li-ion-coordinating diluent, for creating a stable SEI in the developed binary salt electrolyte. The enhanced dipole–dipole interactions weaken the coordination between Li-ions and the solvents while strengthening the interaction between Li-ions and dual anions, thereby facilitating the Li-ion transport and a robust anion-derived SEI with a distinct bilayer structure. Consequently, the developed electrolyte exhibited exceptional electrochemical performance in high energy-density Li||LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811) cells, with long calendar life, stable cyclability at 1 C, and reliable operation between 25 and −20 °C, and it also demonstrat remarkable cycling stability for a Li||NMC811 pouch cell with projected energy density of 402 Wh kg −1 , maintaining 80% capacity retention over 606 cycles under practical conditions.

25 ENERGY STORAGE↗
DOE OSTI2025

Probing Electrode Transformation under Dynamic Operation for Alkaline Water Electrolysis

Alkaline water electrolyzers (AWEs) play a pivotal role in the realm of large-scale hydrogen production. However, AWEs face significant challenges in electrode degradation particularly under dynamic operating conditions, induced by reverse current phenomenon during frequent startup/shutdown. Herein, this study aims to rationalize the degradation mechanisms of AWEs under these conditions. A three-electrode membrane electrode assembly (MEA) setup is first utilized to decouple polarization behaviors of anode and cathode in AWEs. Following a proposed accelerated stress testing protocol, the setup allows for tracking individual electrode performance transformations during frequent reverse current operation. Integrating operando cell studies with in situ and post-mortem characterizations, it is showed that continuous formation of highly active species, nickel (oxy)hydroxides, improves the anode performance for oxygen evolution reaction. On the contrary, irreversible oxidation of nickel to β-nickel hydroxide results in a severe degradation of cathode, leading to material dissolution, poor electrical conductivity and loss of catalytic activity for hydrogen evolution reaction. These results provide insights in nickel-based electrode transformation mechanisms for alkaline water electrolysis and indicate that cathode with higher redox reversibility can potentially improve durability of AWEs under dynamic conditions.

08 HYDROGEN↗
DOE OSTI2025

Structural Tuning of Self‐Conductive Polymer as Gas Diffusion Layer for Electrocatalytic Reactions at High Current

Electrocatalytic conversions offer a promising route for sustainable chemical production using renewable energy. Gas diffusion layers (GDLs) enable selective product formation at high current densities but suffer from electrolyte flooding, and polytetrafluoroethylene (PTFE)-based GDLs typically require metal conductive layers, which constrain catalyst development. A recently developed GDL configuration, electropolymerized poly(3,4-ethylenedioxythiophene) (PEDOT)-coated PTFE, demonstrates notable flooding resistance, but suffers from gas diffusion limitations at elevated currents due to limited gas diffusion through the PEDOT layer. Here, different dopants in PEDOT are exploited to modify the physical properties and enhance gas transport. ClO 4 − -doped PEDOT exhibits superior performance due to optimized physical structure, leading to increased gas permeance and faradaic efficiency (FE) for CO production during electrocatalytic CO 2 reduction. Further optimization of coverage and thickness achieved by adjusting charge density led to an optimal configuration at 33 mC cm −2 . This GDL supports various metal electrocatalysts and demonstrates FE CO of > 90% for over 150 h at −200 mA cm −2 using a commercial silver electrocatalyst. This work highlights the importance of GDL engineering in enhancing performance and durability for long-term electrocatalytic processes.

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

Decoding Gas Evolution Pathways and Interfacial Chemistry in Layered Oxide Cathodes for Safer Sodium‐Ion Batteries

Sodium-ion batteries (SIBs) are attractive for the low cost and abundance of sodium. Yet, gas evolution—a critical challenge in SIBs—remains underexplored. Here, online electrochemical mass spectrometry is used to probe gas evolution in layered oxide cathodes with various compositions, cutoff voltages, dopants, and particle morphologies. Compared to LiNiO 2 (LNO), NaNiO 2 releases more gas, even at lower states of charge, due to the higher covalency of Ni─O bond caused by the more ionic Na─O bond through the inductive effect. Among Co, Mn, Al, and Mg, Mn and Mg doping suppress gas release most effectively by enhancing the metal-oxygen bond strength. NaNi 1/3 Fe 1/3 Mn 1/3 O 2 (NFM) cathodes synthesized via coprecipitation (CP-NFM) and solid-state routes exhibit distinct particle morphologies; CP-NFM exhibits more gas evolution, yet secondary particle morphology helps reduce it through differential cathode-electrolyte reactivity between inner and outer primary particles. Among Li, Ti, Mg, and Cu doping in NFM, Li has the largest effect, reducing gas levels comparable to LNO. Nuclear magnetic resonance and X-ray photoelectron spectroscopies reveal that electrolyte solvent decomposition mainly produces organic-rich cathode-electrolyte interphase (CEI) rather than soluble species. NaPF 6 salt further exacerbates cathode-electrolyte reactions, forming surface Na 2 O species. The findings provide actionable guidance for designing safer, durable SIBs.

25 ENERGY STORAGE↗
DOE OSTI2026

Engineering Thermally Resilient and Kinetically Active Reversible Protonic Ceramic Cells via Interfacial Design

Achieving concurrent fast electrode kinetics and long-term thermo-mechanical durability remains a critical challenge for reversible protonic ceramic electrochemical cells (R-PCECs). Herein, we report an interfacial engineering strategy that integrates a perovs.kite-type PrBaRu0.1Co1.9O5+δ (PBRC) nanoparticle layer onto a PrBa0.5Sr0.5Co1.5Fe0.5O5+δ (PBSCF) substrate (PBRC-PBSCF), together with a modified pellet-assisted sintering approach to fabricate dense BaZr0.4Ce0.4Y0.1Yb0.1O3-δ (BZCYYb4411) electrolytes. The in situ reconstructed heterointerface enhances oxygen reduction/evolution reaction (ORR/OER) kinetics, promotes H2O adsorption/dissociation, and improves steam tolerance, as verified by electrochemical measurements and interfacial microstructural analyses. Density functional theory reveals that Ru-induced electronic modulation at the PBRC-PBSCF interface lowers the energy of oxygen vacancy formation and optimizes the position of the O 2p band center, thereby accelerating oxygen redox kinetics and stabilizing the interface. The resulting R-PCECs deliver an excellent peak power density of 1.112 W cm−2 and an electrolysis current density of −1.257 A cm−2 at 1.3 V in 3% H2O wet air at 600°C, with a reasonable faradaic efficiency. Furthermore, the cells demonstrate excellent stability, sustaining 100 h of thermal cycling (400–600°C, 200°C h−1) in both fuel cell and electrolysis modes, with 600 h of stability in electrolysis mode (600°C, −0.5 to −2 A cm−2).

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2022

Correlation of Oxygen Anion Redox Activity to In‐Plane Honeycomb Cation Ordering in Na x Ni y Mn 1− y O 2 Cathodes

Sodium‐ion batteries (SIBs) are one of the most promising next‐generation energy storage systems because of their abundant and low‐cost component materials. However, the lower energy density of SIBs compared with lithium‐ion batteries diminishes their practical value proposition. Among the many sodium‐based cathodes, layered transition metal oxides with high sodium content have energy densities comparable with the lithium‐ion battery technology. When charged above 4.1 V, the sodium‐based cathodes often undergo transformations because the activation of oxygen anion redox causes irreversible oxygen release, transition metal ion migration, lattice distortion, and rapid capacity decay. Here, in situ gas analysis is performed to evaluate the lattice oxygen anion redox activity in Na x Ni y Mn 1− y O 2 cathodes with P2 and O3 structural orderings. Operando X‐ray diffraction and neutron diffraction are performed to assess the structural changes related to lattice oxygen redox and transition metal ion migration in Na x Ni y Mn 1− y O 2 cathodes. The results unveil that in‐plane honeycomb cationic ordering can help suppress oxygen anion redox activity, which is critical for the future design of layered transition metal oxide cathodes that are prone to achieve high‐energy for durable SIBs.

25 ENERGY STORAGE↗
DOE OSTI2020

Beyond the Polysulfide Shuttle and Lithium Dendrite Formation: Addressing the Sluggish Sulfur Redox Kinetics for Practical High‐Energy Li‐S Batteries

Abstract Electrolyte modulation simultaneously suppresses polysulfide the shuttle effect and lithium dendrite formation of lithium–sulfur (Li‐S) batteries. However, the sluggish S redox kinetics, especially under high S loading and lean electrolyte operation, has been ignored, which dramatically limits the cycle life and energy density of practical Li‐S pouch cells. Herein, we demonstrate that a rational combination of selenium doping, core–shell hollow host structure, and fluorinated ether electrolytes enables ultrastable Li stripping/plating and essentially no polysulfide shuttle as well as fast redox kinetics. Thus, high areal capacity (>4 mAh cm −2 ) with excellent cycle stability and Coulombic efficiency were both demonstrated in Li metal anode and thick S cathode (4.5 mg cm −2 ) with a low electrolyte/sulfur ratio (10 μL mg −1 ). This research further demonstrates a durable Li‐Se/S pouch cell with high specific capacity, validating the potential practical applications.

Zhao, Chen↗
DOE OSTI2020

An Active‐Site Sulfonate Group Creates a Fast Water Oxidation Electrocatalyst That Exhibits High Activity in Acid

Abstract The storage of solar energy in chemical bonds will depend on pH‐universal catalysts that are not only impervious to acid, but actually thrive in it. Whereas other homogeneous water oxidation catalysts are less active in acid, we report a catalyst that maintained high electrocatalytic turnover frequency at pH values as low as 1.1 and 0.43 ( k cat =1501±608 s −1 and 831±254 s −1 , respectively). Moreover, current densities, related to catalytic reaction rates, ranged from 15 to 50 mA cm −2 mM −1 comparable to those reported for state‐of‐the‐art heterogeneous catalysts and 30 to 100 times greater than those measured for two prominent literature homogeneous catalysts at pH 1.1 and 0.43. The catalyst also exhibited excellent durability when a chemical oxidant was used (Ce IV , 7400 turnovers, TOF 0.88 s −1 ). Preliminary computational studies suggest that the unusual active‐site sulfonate group acts a proton relay even in strong acid, as intended.

Nash, Aaron G.↗
DOE OSTI2021

Dynamically Unveiling Metal–Nitrogen Coordination during Thermal Activation to Design High‐Efficient Atomically Dispersed CoN 4 Active Sites

Abstract We elucidate the structural evolution of CoN 4 sites during thermal activation by developing a zeolitic imidazolate framework (ZIF)‐8‐derived carbon host as an ideal model for Co 2+ ion adsorption. Subsequent in situ X‐ray absorption spectroscopy analysis can dynamically track the conversion from inactive Co−OH and Co−O species into active CoN 4 sites. The critical transition occurs at 700 °C and becomes optimal at 900 °C, generating the highest intrinsic activity and four‐electron selectivity for the oxygen reduction reaction (ORR). DFT calculations elucidate that the ORR is kinetically favored by the thermal‐induced compressive strain of Co−N bonds in CoN 4 active sites formed at 900 °C. Further, we developed a two‐step (i.e., Co ion doping and adsorption) Co‐N‐C catalyst with increased CoN 4 site density and optimized porosity for mass transport, and demonstrated its outstanding fuel cell performance and durability.

He, Yanghua↗
DOE OSTI2022

Creating Frustrated Lewis Pairs in Defective Boron Carbon Nitride for Electrocatalytic Nitrogen Reduction to Ammonia

Abstract The electrocatalytic nitrogen reduction reaction (NRR) on metal‐free catalysts is an attractive alternative to the industrial Haber–Bosch process. However, the state‐of‐the‐art metal‐free electrocatalysts still suffer from low Faraday efficiencies and low ammonia yields. Herein, we present a molecular design strategy to develop a defective boron carbon nitride (BCN) catalyst with the abundant unsaturated B and N atoms as Lewis acid and base sites, which upgrades the catalyst from a single “Lewis acid catalysis” to “frustrated Lewis pairs (FLPs) catalysis.” 14 N 2 / 15 N 2 exchange experiments and density functional theory (DFT) calculations reveal that FLPs can adsorb an N 2 molecule to form a six‐membered ring intermediate, which enables the cleavage of N 2 via a pull–pull effect, thereby significantly reducing the energy barrier to −0.28 eV. Impressively, BCN achieves a high Faraday efficiency of 18.9 %, an ammonia yield of 20.9 μg h −1 mg −1 cat. , and long‐term durability.

Lin, Wenwen↗