Search NASA⌕ Search

SEARCH · Search NASA

Results for “ionic conductivity”

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 1,279 records · Page 71
All sourcesNASA NTRSDOE OSTI
DOE OSTI2022

Reprocessable and Recyclable Polymer Network Electrolytes via Incorporation of Dynamic Covalent Bonds

Mechanically durable polymer network electrolytes are desirable for batteries; however, covalent cross-linking adversely affects their large-scale manufacturing, and they are difficult to recycle post-lifespan. In this work, we address the electrolyte reprocessability and recyclability challenges through the use of dynamic covalent bonds for polymer network solid electrolytes. Specifically, the associative dynamic vinylogous urethane motif is incorporated into a poly(ethylene oxide) network electrolyte containing lithium bis(fluorosulfonyl)imide (LiFSI) salt. The resulting dynamic covalent network electrolyte possesses a modest ion conductivity (~10–5 S/cm at room temperature) and good reprocessability. Stress–relaxation studies indicate that the LiFSI salt can catalyze the bond exchange and enhance the network dynamics. Furthermore, the reprocessability associated with bond exchange can be tuned by simply adjusting the formulation of reagent compositions, in which increasing the amount of excess amine or using a shorter chain of PEO prepolymer can further enhance the network dynamics and corresponding reprocessability.

25 ENERGY STORAGE↗
DOE OSTI2018

Conducting properties of nanocomposite polymer electrolytes based on polyethylene glycol diacrylate and SiO{sub 2} nanoparticles at the interface with a lithium electrode

Nanocomposite polymer electrolytes based on polyethylene glycol diacrylate and 1 M LiBF{sub 4} solution in γ-butyrolactone with addition of SiO{sub 2} nanoparticles were synthesized and studied. Resistance measurement at the Li/electrolyte and Li/nanocomposite electrolyte interface by the time-resolved electrochemical impedance showed its significant decrease in the presence of SiO{sub 2} nanoparticles. Charge-discharge cycling of prototypes of Li/LiFePO{sub 4} batteries for 50 cycles also showed the advantage of using nanocomposite polymer electrolytes over electrolytes without SiO{sub 2} additives.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2018

Increase in the Fluorine-Ion Conductivity of Single Crystals of Tysonite-type CeF{sub 3} Superionic Conductor by Substituting Polarized Cd{sup 2+} Ions for Ce{sup 3+} Ions

The fluorine-ion conductivity of single crystals with a tysonite (LaF{sub 3}) structure with heterovalent isomorphic substitutions of highly polarizable Cd{sup 2+} cations with a 18-electron shell for rare earth ions Ce{sup 3+} have been studied for the first time. Ce{sub 0.995}Cd{sub 0.005}F{sub 2.995} single crystals have been grown from melt by the Bridgman technique in a fluorinating atmosphere. The fluorine-ion conductivity of single crystal is measured by impedance spectroscopy in the temperature range from 153 to 1073 K, where it increases by a factor of 10{sup 9}, approaching the value σ{sub dc} = 5 × 10{sup –2} S/cm at 1073 K. At T{sub 0} = 450 ± 20 K, the dependence σ{sub dc}(T) is split into two portions with the ion-transport activation enthalpy ΔH{sub σ} = 0.39 ± 0.01 eV (T < T{sub 0}) and ΔH{sub σ} = 0.23 ± 0.02 eV (T > T0). It is found that at T = 293 K the conductivity σ{sub dc} = 3 × 10{sup –5} S/cm of Ce{sub 0.995}Cd{sub 0.005}F{sub 2.995} crystal is higher by a factor of 10 than the conductivity of the tysonite matrix CeF{sub 3} and close to the σ{sub dc} value for Ce{sub 0.995}Sr{sub 0.005}F{sub 2.995} crystal. This finding indicates a significant effect of the substitutions of Cd{sup 2+} ions for Ce{sup 3+} on the σdc value and the advantage of Cd{sup 2+} ions over Ca{sup 2+} and Ba{sup 2+} from the viewpoint of increasing σ{sub dc}.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2021

New Cost-Effective Halide Solid Electrolytes for All-Solid-State Batteries: Mechanochemically Prepared Fe 3+ -Substituted Li 2 ZrCl 6

Owing to the combined advantages of sulfide and oxide solid electrolytes (SEs), that is, mechanical sinterability and excellent (electro)chemical stability, recently emerging halide SEs such as Li 3 YCl 6 are considered to be a game changer for the development of all-solid-state batteries. However, the use of expensive central metals hinders their practical applicability. In this study, a new halide superionic conductors are reported that are free of rare-earth metals: hexagonal close-packed (hcp) Li 2 ZrCl 6 and Fe 3+ -substituted Li 2 ZrCl 6 , derived via a mechanochemical method. Conventional heat treatment yields cubic close-packed monoclinic Li 2 ZrCl 6 with a low Li + conductivity of 5.7 × 10 –6 S cm –1 at 30 °C. In contrast, hcp Li 2 ZrCl 6 with a high Li + conductivity of 4.0 × 10 –4 S cm –1 is derived via ball-milling. More importantly, the aliovalent substitution of Li 2 ZrCl 6 with Fe 3+ , which is probed by complementary analyses using X-ray diffraction, pair distribution function, X-ray absorption spectroscopy, and Raman spectroscopy measurements, drastically enhances the Li + conductivity up to ≈1 mS cm –1 for Li 2.25 Zr 0.75 Fe 0.25 Cl 6 . The superior interfacial stability when using Li 2+ x Zr 1– x Fe x Cl 6 , as compared to that when using conventional Li 6 PS 5 Cl, is proved. Furthermore, an excellent electrochemical performance of the all-solid-state batteries is achieved via the combination of Li 2 ZrCl 6 and single-crystalline LiNi 0.88 Co 0.11 Al 0.01 O 2 .

25 ENERGY STORAGE↗
DOE OSTI2023

Design and Synthesis of Cubic K 3−2 x Ba x SbSe 4 Solid Electrolytes for K–O 2 Batteries

Developing K-ion conducting solid-state electrolytes (SSEs) plays a critical role in the safe implementation of potassium batteries. In this work, a chalcogenide-based potassium ion SSE is reported, K 3 SbSe 4 , which adopts a trigonal structure at room temperature. Single-crystal structural analysis reveals a trigonal-to-cubic phase transition at the low temperature of 50 °C, which is the lowest among similar compounds and thus provides easy access to the cubic phase. The substitution of barium for potassium in K 3 SbSe 4 leads to the creation of potassium vacancies, expansion of lattice parameters, and a transformation from a trigonal phase to a cubic phase. As a result, the maximum conductivity of K 3−2x Ba x SbSe 4 reaches around 0.1 mS cm −1 at 40 °C for K 2.2 Ba 0.4 SbSe 4 , which is over two orders of magnitude higher than that of undoped K 3 SbSe 4 . This novel SSE is successfully employed in a K–O 2 battery operating at room temperature where a polymer-laminated K 2.2 Ba 0.4 SbSe 4 pellet serves as a separator between the oxygen cathode and the potassium metal anode. Effective protection of the K metal anode against corrosion caused by O 2 is demonstrated.

25 ENERGY STORAGE↗
DOE OSTI2020

A novel equivalent circuit for GDC-based solid oxide cells considering the variations of cell resistances under load

Regarding the mixed ionic-electronic conductive electrolytes, there are several constant assumptions about cell resistances and transference numbers. In this work, the charge transport frameworks of mixed conductive SOCs are comprehensively illustrated. And the independent external current density is introduced into the equivalent circuit for considering the variations of cell resistances under load. The updated expressions of cell resistances together with transference numbers are deduced rigorously based on the equivalent circuit. Electrolyte-supported NiO-GDC/GDC/LSCF cells are tested, and the experimental results validate the variations of cell resistances, especially for the polarization resistance. The comparisons show that electron hole resistances together with transference number calculated by the updated expressions are larger than those obtained by Liu’s method. More accurate transference number and cell resistances under load can be achieved by using the proposed method in this study.

25 ENERGY STORAGE↗
DOE OSTI2024

Theoretical design and performance of three-dimensional, pillared FeS 2 cathodes

Three-dimensional (3D) electrode design can provide improved capacities and rate capabilities over conventional two-dimensional electrodes by enhancing electrical and ionic transport. Here, expanding upon our previous modeling efforts for conversion chemistry lithium-ion batteries, we develop a pseudo-four-dimensional (P4D) approach that is subsequently used to investigate the design of a pillared FeS 2 electrode. The model considers transport in three dimensions with an additional “fourth” dimension corresponding to the solid-state lithium transport within the active material particles. Additionally, we allow for expansion of the active material during the conversion reaction to understand how internal stresses impact the electrochemical performance of the cell. By optimizing the model with respect to areal capacity, we are able to predict areal capacities up to 16.8 mAh/cm 2 for an areal current density of 1.78 mA/cm 2 and a 103% improvement for the three-dimensional electrodes over planar electrodes of equal volume. Despite the promising results, our simulations suggest that 3D design may be difficult for conversion cathode materials due to the large internal stresses that arise during conversion. Nevertheless, the model is robust and adaptable to other materials that may be more suitable for 3D electrodes due to a lesser change in volume during discharge.

Conversion cathode materials↗
DOE OSTI2024

Hydrogen in energy and information sciences

Beyond its fascinating chemistry as the first element in the Periodic Table, hydrogen is of high societal importance in energy technologies and of growing importance in energy-efficient computing. In energy, hydrogen has reemerged as a potential solution to long-term energy storage and as a carbon-free input for materials manufacturing. Its utilization and production rely on the availability of proton-conducting electrolytes and mixed proton–electron conductors for the components in fuel cells and electrolyzers. In computing, proton mediation of electronic properties has garnered attention for electrochemically controlled energy-efficient neuromorphic computing. Incorporation of substitutional and interstitial hydride ions in oxides, though only recently established, enables tuning of electronic and magnetic properties, inviting a range of possible exotic applications. This article addresses common themes in the fundamental science of hydrogen incorporation and transport in oxides as relevant to pressing technological needs. The content covers (1) lattice (or bulk) mechanisms of hydrogen transport, primarily addressing proton transport, but also touching on hydride ion transport; (2) interfacial transport; (3) exploitation of extreme external drivers to achieve unusual response; and (4) advances in methods to probe the hydrogen environment and transport pathway. The snapshot of research activities in the field of hydrogen-laden materials described here underscores exciting recent breakthroughs, remaining open questions, and breathtaking experimental tools now available for unveiling the nature of hydrogen in solid-state matter.

08 HYDROGEN↗
DOE OSTI2018

Characteristics of the Li{sup +}-Ion Conductivity of Li{sub 3}R{sub 2}(PO{sub 4}){sub 3} Crystals (R = Fe, Sc) in the Superionic State

The characteristics of Li+-ion conductivity σdc of structural γ modifications of Li{sub 3}R{sub 2}(PO{sub 4}){sub 3} compounds (R = Fe, Sc) existing in the superionic state have been investigated by impedance spectroscopy. The type of structural framework [R{sub 2}P{sub 3}O{sub 12}]{sub ∞}{sup 3-} affects the σdc value and the σdc activation enthalpy in these compounds. The ion transport activation enthalpy in γ-Li{sub 3}R{sub 2}(PO{sub 4}){sub 3} (ΔH{sub σ} = 0.31 ± 0.03 eV) is lower than in γ-Li{sub 3}Fe{sub 2}(PO{sub 4}){sub 3} (ΔH{sub σ} = 0.36 ± 0.03 eV). The conductivity of γ-Li{sub 3}Fe{sub 2}(PO{sub 4}){sub 3} (σ{sub dc} = 0.02 S/cm at 573 K) is twice as high as that of γ-Li{sub 3}R{sub 2}(PO{sub 4}){sub 3}. A decrease in temperature causes a structural transformation of Li{sub 3}R{sub 2}(PO{sub 4}){sub 3} from the superionic γ modification (space group Pcan) through the intermediate metastable β modification (space group P2{sub 1}/n) into the “dielectric” α modification (space group P2{sub 1}/n). Upon cooling, σdc for both phosphates decreases by a factor of about 100 at the superionic TSIC transition. In Li{sub 3}Fe{sub 2}(PO{sub 4}){sub 3} σdc gradually decreases in the temperature range T{sub SIC} = 430–540 K, whereas in Li{sub 3}R{sub 2}(PO{sub 4}){sub 3} σdc undergoes a jump at T{sub SIC} = 540 ± 25 K. Possible crystallochemical factors responsible for the difference in the σdc and ΔH{sub σ} values and the thermodynamics and kinetics of the superionic transition for Li{sub 3}R{sub 2}(PO{sub 4}){sub 3} are discussed.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

X-ray photoelectron spectroscopy and ion dynamics study of W6+ doped La2Mo2O9 as SOFC electrolyte

Highlights: • Stabilization of high temperature cubic phase of La{sub 2}Mo{sub 2}O{sub 9} at room temperature by W doping. • Intra-granular pore formation in the material under reducive atmosphere. • X-ray photoelectron spectroscopic study of W doped La{sub 2}Mo{sub 2}O{sub 9} both in air and reducive atmosphere. • Partial stabilization of Mo{sup 6+} state in La{sub 2}Mo{sub 2}O{sub 9} upon W doping in reducive atmosphere. • Ion dynamics and conductivity studies for oxide ion transport. - Abstract: The structural stability of La{sub 2}Mo{sub 2-x}W{sub x}O{sub 9} is well reported by many researchers but its studies on photoelectron spectroscopy, structural behaviour in Ar-H{sub 2} (reducing) atmosphere and ion dynamics are rarely reported. Here we report for the first time, to the best of authors’ knowledge, the above studies for W-doped La{sub 2}Mo{sub 2}O{sub 9} compounds. La{sub 2}Mo{sub 2}O{sub 9} doped with W{sup 6+} over the range of 0.25 ≤ x ≤ 1.75 at Mo{sup 6+} site is synthesised by solid-state reaction route. The x-ray diffraction studies show that at x = 0.5 the lattice parameter of the unit cell starts decreasing as a consequence of decrease in bond length between various elements present in the compound. The XPS analysis shows that Mo in La{sub 2}Mo{sub 2-x}W{sub x}O{sub 9} is very much sensitive to reduction. The temperature dependent a.c. impedance spectroscopy study of La{sub 2}Mo{sub 2-0.5}W{sub 0.5}O{sub 9} has been reported over the temperature range up to 653 K.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Electrosynthesis of Ti{sub 5}Si{sub 3}, Ti{sub 5}Si{sub 3}/TiC, and Ti{sub 5}Si{sub 3}/Ti{sub 3}SiC{sub 2} from Ti-Bearing Blast Furnace Slag in Molten CaCl{sub 2}

Ti{sub 5}Si{sub 3}, Ti{sub 5}Si{sub 3}/TiC, and Ti{sub 5}Si{sub 3}/Ti{sub 3}SiC{sub 2} have been electrochemically synthesized from the Ti-bearing blast furnace slag/TiO{sub 2} and/or C mixture precursors at a cell voltage of 3.8 V and 1223 K to 1273 K (950 °C to 1000 °C) in molten CaCl{sub 2}. The pressed porous mixture pellets were used as the cathode, and a solid oxide oxygen-ion-conducting membrane (SOM)-based anode was used as the anode. The phase composition and morphologies of the cathodic products were systematically characterized. The final products possess a porous nodular microstructure due to the interconnection of particles. The variations of impurity elements, i.e., Ca, Mg, and Al, have been analyzed, and the result shows that Ca and Mg can be almost completely removed; however, Al cannot be easily removed from the pellet due to the formation of Ti-Al alloys during the electroreduction process. The electroreduction process has also been investigated by the layer-depended phase composition analysis of the dipped/partially reduced pellets to understand the detailed reaction process. The results indicate that the electroreduction process of the Ti-bearing blast furnace slag/TiO{sub 2} and/or C mixture precursors can be typically divided into four periods, i.e., (i) the decomposition of initial Ca(Mg,Al)(Si,Al){sub 2}O{sub 6}, (ii) the reduction of Ti/Si-containing intermediate phases, (iii) the removal of impurity elements, and (iv) the formation of Ti{sub 5}Si{sub 3}, TiC, and Ti{sub 3}SiC{sub 2}. It is suggested that the SOM-based anode process has great potential to be used for the direct and facile preparation of Ti alloys and composites from cheap Ti-containing ores.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Enhanced Optical Contrast and Switching in Near‐Infrared Electrochromic Devices by Optimizing Conjugated Polymer Oligo(Ethylene Glycol) Sidechain Content and Gel Electrolyte Composition

Abstract A detailed investigation addressing the effects of functionalizing conjugated polymers with oligo(ethylene glycol) (EG n ) sidechains on the performance and polymer‐electrolyte compatibility of electrochromic devices (ECDs) is reported. The electrochemistry for a series of donor‐acceptor copolymers having near‐infrared (NIR)‐optical absorption, where the donor fragment is 3,4‐ethylenedioxythiophene (EDOT) or an EG n functionalized bithiophene (g2T) and the acceptor fragment is diketopyrrolopyrrole (DPP) functionalized with branched alkyl or EG n sidechains, is extensively probed. ECDs are next fabricated and it is found that EG n sidechain incorporation must be finely balanced to promote polymer‐electrolyte compatibility and provide efficient ion exchange. Proper electrolyte‐cation pairing and polymer structural tuning affords a 2x increase in optical contrast (from 12% to 24%) and >60x reduction in switching time (from 20 to 0.3 s). Atomic force microscopy (AFM)/grazing incidence wide‐angle X‐ray scattering (GIWAXS) characterization of the polymer film morphology/microstructure reveals that an over‐abundance of EG n sidechains generates large polymer crystallites, which can suppress ion exchange. Lastly, time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) indicates sidechain/electrolyte identity does not influence the electrolyte penetration depth into the films, and EG n sidechain inclusion increases electrolyte cation uptake. The material structural design insight and guidelines regarding the polymer‐electrolyte ion insertion/expulsion dynamics reported here should be of significant utility for developing next‐generation mixed ionic‐electronic conducting materials.

Chemistry↗
DOE OSTI2019

Quantification of Heterogeneous Degradation in Li-Ion Batteries

The multiscale chemomechanical interplay in lithium-ion batteries builds up mechanical stress, provokes morphological breakdown, and leads to state of charge heterogeneity. Quantifying the interplay in complex composite electrodes with multiscale resolution constitutes a frontier challenge in precisely diagnosing the fading mechanism of batteries. In this work, hard X-ray phase contrast tomography, capable of nanoprobing thousands of active particles at once, enables an unprecedented statistical analysis of the chemomechanical transformation of composite electrodes under fast charging conditions. The damage heterogeneity is demonstrated to prevail at all length scales, which stems from the unbalanced electron conduction and ionic diffusion, and collectively leads to the nonuniform utilization of active particles spatially and temporally. This research highlights that the statistical mapping of the chemomechanical transformation offers a diagnostic method for the particles utilization and fading, hence could improve electrode formulation for fast-charging batteries.

25 ENERGY STORAGE↗
DOE OSTI2019

Accelerated Oxygen Mass Transfer in Copper and Vanadium Oxide-Based MIEC-Redox Membrane

Mixed ionic-electronic conducting (MIEC) membranes have a great potential for use in gas separation technology in the production of pure oxygen for metallurgy, micro- and nanoelectronics, biotechnology, pharmaceutics, etc. Before this happens, an important issue has to be addressed. This issue involves the design of novel MIEC membranes with enhanced oxygen transport. Recently, a concept of thick two-layer solid/liquid composite MIEC-Redox membranes with accelerated diffusion-bubbling oxygen transfer was proposed (see Belousov and Fedorov in ACS Appl Mater Interfaces 10:21794–21798, 2018). These diffusion-bubbling membranes could serve for efficient oxygen separation from air. However, there is no enough fundamental understanding of the mass transport processes involved. This understanding is important for evaluating the potential of MIEC-Redox membranes for practical application. The presented article gives a theory of oxygen mass transfer in two-layer copper and vanadium oxide-based MIEC-Redox membranes. The theory describes both the transport of oxygen ions in the outer layer of the membrane and the nucleation, growth, and transport of oxygen gas bubbles in the inner layer of the membrane. Kinetic regularities of oxygen mass transfer are established. The ways to enhance the productivity of MIEC-Redox membranes are outlined.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Review on Low-Temperature Electrolytes for Lithium-Ion and Lithium Metal Batteries

Abstract Among various rechargeable batteries, the lithium-ion battery (LIB) stands out due to its high energy density, long cycling life, in addition to other outstanding properties. However, the capacity of LIB drops dramatically at low temperatures (LTs) below 0 °C, thus restricting its applications as a reliable power source for electric vehicles in cold climates and equipment used in the aerospace. The electrolyte engineering has proved to be one of the most effective approaches to mitigate LIB performance degradation at LTs. In this review, we summarize the important factors contributing to the deterioration in Li + transport and capacity utilization at LTs while systematically categorize the solvents, salts and additives reported in the literature. Strategies to improve the Li + transport kinetics, in the bulk electrolyte and across the interphases, are discussed. In particular, the formation mechanism of solid electrolyte interphase and its functionality for LT electrolytes are analyzed. Perspectives on the future evolution of this area are also provided. Graphical abstract

25 ENERGY STORAGE↗
DOE OSTI2023

Liquid electrolytes for low-temperature lithium batteries: main limitations, current advances, and future perspectives

Lithium-ion batteries (LIBs) can now be used in almost all modern electronic devices and electric vehicles. However, as the range of applications increases, the challenges increase as well, especially at very low temperatures. Many individual processes could result in capacity loss of LIBs at low temperatures; however, most of them are associated with the liquid electrolyte inside the battery. In this review, we first discuss the main limitations in developing liquid electrolytes used in low-temperature LIBs, and then we summarize the current advances in low-temperature electrolytes, including lithium salts, solvents, additives, and new strategies. Finally, we present some perspectives on the current state of low-temperature electrolytes for LIBs, outlining the most promising research areas in this field. In conclusion, this review will provide useful insights into the design of cryogenic electrolytes and the path forward to the widespread use of LIBs in cryogenic environments.

25 ENERGY STORAGE↗