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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 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

An epoxy-reinforced ceramic sheet as a durable solid electrolyte for solid state Na-ion batteries

In a conventional Na-ion battery system using liquid electrolyte, there are critical safety issues due to the instability of the liquid electrolyte. Na 3 Zr 2 Si 2 PO 12 (NASICON) solid electrolyte is a material that is sufficient to replace a liquid electrolyte as it has high ionic conductivity and thermal and electrochemical stability. However, as there is a large interfacial resistance in the NASICON solid electrolyte powder, even when used in combination with a polymer electrolyte, the advantageous effects of ceramics are not easily exhibited. In this study, we propose a top-down method of combining a polymer with a ceramic in which an ion transport channel is previously formed. In this method, a NASICON solid electrolyte is partially sintered to form ion transport channels. Then the NASICON solid electrolyte pores are filled with an epoxy polymer to increase the strength of the epoxy-NASICON composite electrolyte. This method demonstrates the possibility of our composite electrolyte being used as a thin and strong film. As a result of our methods, the ionic conductivity and thermal and electrochemical stability of NASICON were maintained, while the physical strength was enhanced by approximately 2 times. In addition, a capacity of 120 mA h g -1 and stability of 20 cycles were confirmed in a half cell with a Na 3 V 2 (PO 4 ) 3 cathode and Na metal. This method proposes a new direction for research regarding composite electrolytes created using an oxide-based solid electrolyte.

25 ENERGY STORAGE↗
DOE OSTI2024

Ion transport in composites of binary electrolyte and single ion conductor—A chronoamperometry study

Composite electrolytes for lithium batteries typically combine materials with very different mechanical properties and ionic transport mechanisms and the degree to which these two phases affect each other is not well understood. In this work we used numerical simulations and experiments to investigate the transport in composite electrolytes consisting of polyethylene oxide (PEO) with Lithium bis-triuoromethanesulfonimide (LiTFSI) and Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 (LATP) lithium ion conducting glass-ceramic particles. In particular we are interested in how the introduction of a single ion conductor (SIC) changes the salt concentration gradients in the polymer electrolyte (PE) under applied potential. To study this, we performed numerical simulations and chronoamperometry experiments in electrolytes with different arrangements of the SIC and PE phases, i.e. layers and particulate composites. The results show that the particulate composites have the highest concentration gradients and take the longest time to reach steady state current. Furthermore, the high concentration gradient can be exacerbated by a high SIC/PE interfacial resistance. Finally, the best arrangement appears to have a layer of SIC impenetrable to anions in the polymer phase within the electrolyte membrane.

25 ENERGY STORAGE↗
DOE OSTI2020

Impact of Ionic Liquid on Lithium Ion Battery with a Solid Poly(Ionic Liquid) Pentablock Terpolymer as Electrolyte and Separator

In this work, a ternary blend solid polymer electrolyte (SPE) consisting of a poly(ionic liquid) (PIL) multiblock polymer, lithium salt, and ionic liquid (IL) was investigated with the goal of understanding the influence of IL concentration on ion transport mechanisms and electrochemical stability. The physical, transport, mechanical, morphological, and electrochemical properties of the ternary blend SPE were systematically investigated as a function of IL concentration (r = [IL]/[PIL] mole ratio between 0.1 and 0.7). The results indicate that with increasing IL concentration, the continuous conductive domain increases along with the polymer chain segmental mobility, as well as facilitate ionic conductivity, while the mechanical modulus exhibits a percolation threshold (from 52.17 MPa to 0.55 MPa at r = 0.2 to 0.3). Surprisingly, at higher IL concentrations, there is a reduction in the lithium cation mobility (i.e., 9.3 × 10-12 m2 s-1 versus 3.8 × 10-12 m2 s-1 for r = 0.2 versus r = 0.5, respectively) as evidenced by pulsed-field gradient nuclear magnetic resonance (PFG-NMR), which coincides with an increased overpotential (i.e., 50 mV versus 150 mV for r = 0.2 versus r = 0.5, respectively) evidenced by lithium metal stripping and plating. This work provides valuable insights into the impact of IL on lithium ion conducting PIL block polymers, which may enable the design of new SPEs with both high ionic conductivity and improved stability for the future lithium ion batteries.

Chen, Tzu-Ling↗
DOE OSTI2026

Covalent adaptable networks for electrolyte–binder integration in recyclable lithium metal batteries

Lithium-metal batteries (LMBs) are considered a promising next-generation energy storage technology due to their exceptionally high energy density. However, the development of solid polymer electrolytes and cathode binders for LMBs faces critical challenges, including interfacial instability, poor recyclability, and growing environmental concerns. In particular, current systems often rely on non-recyclable components featuring permanently crosslinked networks and polyfluoroalkyl substances (PFAS), such as poly(vinylidene fluoride) (PVDF), which cause battery waste and environmental harm. Herein, we introduce a multifunctional covalent adaptable network (CAN) platform based on thermally reversible Diels–Alder (DA) chemistry, designed for dual functionality as a CAN-based electrolyte (CAE) and a CAN-based cathode binder. The CAE achieves high ionic conductivity and strong storage modulus (1.4 mS cm −1 and ∼ 10 5 Pa at room temperature, respectively) and enables stable long-term cycling in symmetric Li||Li cells for over 2000 h with low overpotential. When it is applied as a cathode binder in LiFePO 4 (LFP) composite electrodes (C-LFP), the CAN matrix significantly reduces interfacial resistance and enhances discharge capacity compared to conventional PVDF-based systems. Thermal treatment induces self-healing at the cathode–electrolyte interface, further improving contact and yielding a discharge capacity of 150 mAh g −1 at 0.5 C. Moreover, the dynamic CAN architecture allows efficient recovery and reuse of lithium salts from spent electrolytes through retro-DA reactions under mild conditions (∼80 °C), establishing a low-energy, cost-effective recycling pathway. In conclusion, this work presents a scalable and sustainable strategy for high-performance LMBs by integrating recyclability, interfacial healing, and PFAS-free design, offering a holistic solution aligned with circular economy principles and next-generation battery demands.

Diels–Alder↗
DOE OSTI2023

Origin of rate limitations in solid-state polymer batteries from constrained segmental dynamics within the cathode

Currently, one of the key challenges preventing the wide commercialization of polymer-based solid-state batteries is achieving high-rate capabilities. This work unravels chain structure and segmental dynamics in a polymer-based composite cathode consisting of LiFePO 4 (LFP), carbon, and poly(ethylene oxide) (PEO) with lithium bis(trifluoromethanesulfonyl)imide. Small-angle neutron scattering (SANS) data reveal that PEO chains are adsorbed on the surface of LFP particles during slurry processing to make the composite electrode. The strong interaction between LFP and PEO chains leads to greatly reduced segmental dynamics of PEO, as discovered by quasi-elastic neutron scattering (QENS). The reduced segmental dynamics results in 70% decreased Li + mobility of the polymer electrolyte in the composite cathode. The combined SANS and QENS study indicates that one of the key bottlenecks that limits the rate performance of PEO-based polymer batteries originates from molecular interactions within the cathode.

25 ENERGY STORAGE↗
DOE OSTI2023

Wide temperature range ultracapacitor

A solid state polymer electrolyte is disclosed for use in an ultracapacitor. The electrolyte includes an ionic liquid and a polymer and may include other additives, wherein an ultracapacitor that utilizes the solid state electrolyte is configured to output electrical energy at temperatures between about −40° C. and about 250° C. or more.

Brambilla, Nicolo Michele↗
DOE OSTI2022

High voltage stable cycling of all-solid-state lithium metal batteries enabled by top-down direct fluorinated poly (ethylene oxide)-based electrolytes

Poly (ethylene oxide) (PEO)-based solid-state polymer electrolytes (SPEs) show prospects in all-solid-state lithium metal batteries. However, they suffer from low ionic conductivity at room temperature and interfacial instability with high voltage cathodes for long-term cycling. In this work, top-down fluorinated PEOs (F-PEOs) for the all-solid-state electrolytes, which are scalable and cost-effective, are developed to improve the battery performance. We demonstrate, that by enhancing the disordering of the F-PEO matrix, the SPE achieves a maximum Li + conductivity of 1.1 x 10 -4 S cm -1 at 40 °C, which is 20 times higher than the baseline. By forming robust cathode/SPE and Li/SPE interfaces, the F-PEO-based SPEs demonstrate stable cycling in the LiFePO 4 /Li and LiNi 0·8 Mn 0·1 Co 0·1 O 2 /Li (3-4.4 V, 500 cycles, capacity retention of 91.6%) based all-solid-state batteries at 40 °C. Therefore, our work highlights the significance of "disordering engineering" for energy storage materials.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

The Effect of Membrane Casting Irregularities on Initial Fuel Cell Performance

Membrane electrode assemblies (MEA) for polymer electrolyte membrane fuel cells (PEMFC) may possess as-manufactured non-uniformities in any of its constituent components. This article studies casting irregularities located within the PEM to understand their potential impact on MEA initial performance. Membrane material was cast on a lab-scale polymer casting line operating either within or at the boundaries of the process window. The resulting membrane material was either pristine in the former case, or, in the latter case, contained air bubbles, cracks, and other irregularities, ranging in size from about 0.6 to 3 mm. Spatial polarization experiments were conducted using a 121-channel segmented fuel cell system, and thermal imaging was performed subsequently to map hydrogen crossover to spatial performance. While total-cell polarization data was minimally impacted by the irregularities, the spatial diagnostics showed local performance impacts that, in operation over time, could cause degradation in performance or earlier failure of the MEA. Such impacts could lead to these irregularities being classified as defects, i.e., manufacturing variations that should be identified and not included in a fuel cell stack. Classification of irregularities as defects will ultimately assist the industry by contributing to the development of threshold detection limits for in-line quality control diagnostics.

30 DIRECT ENERGY CONVERSION↗
DOE OSTI2023

Hydrocarbon Ionomeric Binders for Fuel Cells and Electrolyzers

Abstract Ionomeric binders in catalyst layers, abbreviated as ionomers, play an essential role in the performance of polymer–electrolyte membrane fuel cells and electrolyzers. Due to environmental issues associated with perfluoroalkyl substances, alternative hydrocarbon ionomers have drawn substantial attention over the past few years. This review surveys literature to discuss ionomer requirements for the electrodes of fuel cells and electrolyzers, highlighting design principles of hydrocarbon ionomers to guide the development of advanced hydrocarbon ionomers.

25 ENERGY STORAGE↗
DOE OSTI2024

Durable High Power Density Fuel Cell Cathodes for Heavy-Duty Vehicles

The aim of this project was to advance the performance and durability of proton exchange membrane fuel cells (PEMFCs) for their use in the electrification of heavy-duty vehicles (HDVs). With an emphasis on total cost of ownership for HDVs, the development of the fuel cells focuses more heavily on the efficiency and lifetime (i.e., durability) than past focus on platinum group metal (PGM) costs and power density. This project takes a unique approach to achieving these goals – using next-generation polymer electrolytes in the electrodes that yield significant improvements in performance and dramatic reductions in degradation rates. A key outcome of the project was an ionomer/catalyst combination of a Pt catalyst on a low surface area carbon support (Pt/LSC) with a high oxygen permeability ionomer (HOPI) that met both the project’s performance target (current at 0.8 V, >0.3 A/cm 2 ) and durability target (voltage loss at 0.8 A/cm 2 , <30 mV) with the goal of projected a >4X increase in life-time.

08 HYDROGEN↗
DOE OSTI2023

Engineering Functionalized 2D Metal-Organic Frameworks Nanosheets with Fast Li + Conduction for Advanced Solid Li Batteries

Solid-state batteries can ensure high energy density and safety in lithium metal batteries, while polymer electrolytes are plagued by slow ion kinetics and low selective transport of Li + . Metal-organic frameworks (MOFs) are proposed as emerging fillers for solid-state poly(ethylene oxide)(PEO) electrolytes, however, developing functionalized MOFs and understanding their roles on ion transfer has proven challenging. Herein, combining computational and experimental results, the functional group regulation in MOFs can effectively change surficial charge distribution and limit anion movement is revealed, providing a potential solution to these issues. Specifically, functionalized 2D MOF sheets are designed through molecular engineering to construct high-performance composite electrolytes, where the electron-donating effect of substituents in 2D-MOFs effectively limits the movement of ClO 4 - and promotes mechanical properties and ion migration numbers (0.36 up to 0.64) of PEO. As a result, Li/Li cells with composite electrolyte exhibit superior cyclability for 1000 h at a current density of 0.2 mA cm -2 . Meanwhile, the solid LiFePO 4 /Li battery delivers highly reversible capacities of 148.8 mAh g -1 after 200 cycles. In conclusion, these findings highlight a new approach for anion confinement through the use of functional group electronic effects, leading to enhanced ionic conductivity, and a feasible direction for high-performance solid-state batteries.

25 ENERGY STORAGE↗
DOE OSTI2020

Effect of salt concentration profiles on protrusion growth in lithium-polymer-lithium cells

In this report, the formation of dendrites and other protrusions on lithium metal anodes is a subject of continued interest due to the potential to incorporate these anodes in next-generation rechargeable batteries with increased energy densities. Solid polymer electrolytes show improved stability against lithium metal compared to liquid carbonate electrolytes. We have studied the effect of salt concentration on the formation of protrusions formed on electrodeposited lithium through a rigid block copolymer electrolyte, polystyrene-block-poly(ethylene oxide) (PS-b-PEO or SEO), in a lithium-lithium symmetric cell. The cell lifetime decreases by a factor of 100 when salt concentration is increased by a factor of 5. Our main objective is to understand the reason for this observation. We show that this decrease is not due to a salt-induced change of the morphology of the block-copolymer electrolyte, nor is it due to a salt-induced change of mechanical properties. We use an approach based on Newman's concentrated solution theory to fully characterize ion transport in the block-copolymer electrolyte, and report the conductivity, salt diffusion coefficient, cation transference number, and thermodynamic factor. Neither cell lifetime nor protrusion density in failed cells correlate with any of these electrochemical parameters. However, the electrochemical parameters can be used to predict salt concentration profiles in our symmetric cells. We posit that an important parameter in protrusion growth is the magnitude of the salt concentration gradient, Δ. We observe a direct correlation between Δ and lithium protrusion growth.

25 ENERGY STORAGE↗
DOE OSTI2021

Simulation of 12-bed vacuum pressure-swing adsorption for hydrogen separation from methanol-steam reforming off-gas

This study focuses on analysis of a 12-bed vacuum pressure-swing adsorption (VPSA) process capable of purifying hydrogen from a ternary mixture (H 2 /CO 2 /CO 75/24/1 mol%) derived from methanol-steam reforming. The process produces 9 kmol H 2 /h with less than 2 ppm and 0.2 ppm of CO2 and CO, respectively, to supply a polymer electrolyte membrane fuel cell. The process model is developed in Aspen Adsorption® using the “uni-bed” approach. A parametric study of H 2 purity and recovery with respect to adsorption pressure, adsorbent height, activated carbon:zeolite ratio, feed composition, and number of beds is performed. Results show 12-bed VPSA can meet the H 2 purity goals, with H 2 recovery as high as 75.75%. Adsorption occurs at 7 bar, the column height is 1.2 m, and the adsorbent ratio is 70%:30%. Furthermore, a 4-bed VPSA can achieve the same purity goals as the 12-bed process, but H 2 recovery decreases to 61.34%.

03 NATURAL GAS↗
DOE OSTI2020

Microstructural Evolution and ORR Activity of Nanocolumnar Platinum Thin Films with Different Mass Loadings Grown by High Pressure Sputtering

Nanocolumnar platinum thin films (Pt-TFs) with different Pt mass loadings were grown by high pressure sputtering (HIPS) and investigated as oxygen reduction reaction (ORR) electrocatalysts for polymer electrolyte membrane fuel cell applications. Mass loading was controlled by changing the sputter deposition time. A cauliflower-like columnar microstructure was achieved by depositing the Pt-TFs onto a microporous layer (MPL)-like surface composed of carbon particles in order to mimic catalyst-coated gas diffusion electrodes. Microstructural evolution of HIPS Pt-TFs and their ORR activity were investigated. Electrochemical characterization of the nanocolumnar Pt-TFs was performed by cyclic voltammetry and rotating disk electrode measurements on Pt-TF/MPL-like-layer/glassy-carbon samples in an aqueous perchloric acid electrolyte. The electrochemically active surface area increased from 18 to 39 m 2 g –1 as the Pt mass loading was decreased. Specific activity of the films was similar (~600 μA cm –2 ) for all Pt mass loadings, due to the similar nanoparticle sizes of ~5 nm as observed by transmission electron microscopy and X-ray diffraction. Furthermore, mass activity of the films increased from 0.11 to 0.26 A mg –1 as the Pt mass loading was decreased, which is an indication of the effective Pt utilization and better access through the catalyst layer at lower Pt mass loadings.

08 HYDROGEN↗
DOE OSTI2026

Relief Zones Enhance the Durability of Ultrathin Membranes in Electrochemical Conversion Devices

Premature failures in electrochemical conversion systems often result when membrane electrode assemblies (MEAs) use ultrathin (≤15 μm-thick) polymer electrolyte membranes, susceptible to mechanical degradation from stress concentrations arising from device-level integration. Herein, relief zones were developed to mitigate mechanical degradation by alleviating excess and nonuniform compression across active areas. Relief zones, created through ablation of carbonaceous diffusion media, enable seamless adaptation across MEA dimensions without need for hardware modifications. Demonstrated using fuel cells as a case study, accelerated stress tests revealed a 6-fold lifetime improvement (∼1500 h) compared to conventional edge-protected MEAs, decoupling device-level engineering effects from material limitations.

accelerated stress test↗
DOE OSTI2023

Machine learning-based surrogate models and transfer learning for derivative free optimization of HT-PEM fuel cells

Widespread adoption of high-temperature polymer electrolyte membrane electrochemical systems, such as fuel cells (HT-PEMFCs), requires models and computational tools for accurate optimization and guiding new materials for enhancing performance and durability. In this contribution, knowledge-based modelling and data-driven modelling are combined using Few-Shot Learning and implementing an Automated Machine Learning framework for the generation of Machine Learning-based surrogate models. Applicability of the resulting model for derivative-free optimization is demonstrated. Additionally, a way of considering extrapolation in the optimization task is presented. Results show that although extrapolation is needed to achieve better solutions during optimization, it can be monitored and managed. As a result, tuning the electrode ionomer binder's properties, such as ionic conductivity, in the fuel cell represents a promising pathway for improving HT-PEMFC performance.

08 HYDROGEN↗
DOE OSTI2020

Single-layer graphene as a highly selective barrier for vanadium crossover with high proton selectivity

In this paper, we report near-zero crossover for vanadium cross-permeation through single-layer graphene immobilized at the interface of two Nafion® polymer electrolyte membranes. Vanadium ion diffusion and migration, including proton mobility through membrane composites, were studied with and without graphene under diffusion and migration conditions. Single-layer graphene was found to effectively inhibit vanadium ion diffusion and migration under specific conditions. The single-layer graphene composites also enabled remarkable ion transmission selectivity improvements over pure Nafion® membranes, with proton transport being four orders of magnitude faster than vanadium ion transport. Resistivity values of 0.02 ± 0.005 Ω cm 2 for proton and 223 ± 4 Ω cm 2 for vanadium ion through single atomic layer graphene are reported. This high selectivity may have significant impact on flow battery applications or for other electrochemical devices where proton conductivity is required, and transport of other species is detrimental. Our results emphasize that crossover may be essentially completely eliminated in some cases, enabling for greatly improved operational viability.

2D nanomaterial↗
DOE OSTI2020

Polyphosphonates as ionic conducting polymers

Polyphosphonates, a class of polymers with the generic formula –[P(R)(X)–OR'O] n –, exhibit a high degree of modularity due to the range of R, R', and X groups that can be incorporated. As such, these polymers may be designed with a polyethylene oxide (PEO) backbone (R' group) and employed as solid polymer electrolytes (SPEs). Two PEO-containing polyphosphonate analogs (R = Ph; X = S or Se) were doped with LiPF 6 and their conductivities were measured. Conductivities were similar (X = S) to or exceeding (X = Se) those of standard PEO systems (just below 10 -4 S/cm at 100°C). Binding models for Li + were generated using 31 P{ 1 H}NMR titration experiments. Binding of Li + by these polyphosphonates followed a positive cooperativity model, and varying the X group (S or Se) affected the observed cooperativity (Hill coefficient = 1.73 and 4.16, respectively). The presence of Se also leads to an increase in conductivity as temperature is raised above the T g , which is likely an effect of reduced Columbic interactions. Finally, because of their modularity and ease with which cation binding can be evaluated using 31 P{ 1 H} NMR titration experiments, polyphosphonates offer a unique approach for the modification of Li + ion battery technology.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗