Search NASA⌕ Search

SEARCH · Search NASA

Results for “superionic 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 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Anion and cation co-doping of Na 4 SnS 4 as sodium superionic conductors

Na based all-solid-state batteries are one of the most promising candidates for large-scale electrochemical energy storage owing to their low cost and outstanding safety properties. The key enabler of this technology is solid electrolyte with sufficiently high ionic conductivity at room temperature. In this work, the design, synthesis, characterization and testing of a series of novel fast Na-ion conductors, Na 4-x-y Sn 1-x A x S 4-y X y with aliovalent cation (P 5+ /Sb 5+ ) and anion substitutions (Cl - /Br - ) of the parent compound Na 4 SnS 4 are reported. The doped samples crystalize in a new phase with space group I4 1 /acd and show ionic conductivities that are one to four orders of magnitude higher than that of undoped Na 4 SnS 4 . R. t. conductivity of 0.64 mS cm -1 is achieved in Na 3.7 Sn 0.8 Sb 0.2 S 3.9 Cl 0.1 with a low activation energy of 0.26 eV. Furthermore, Rietveld refinement against high resolution synchrotron X-ray powder diffraction data reveals that the distribution of the doping ions and the resulted Na vacancies are underlying cause of the enhanced conductivity.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Elucidating the Determinants of Alkali Ionic Conductivity in Oxide and Sulfide Frameworks

The aim of this project is to elucidate the structural and chemical factors determining alkali conductivity in oxide and sulfide frameworks using large scale first principles calculations and topological analysis. The facile conduction of alkali ions in oxide and sulfide host structures is of critical importance in energy storage. Today, the dominant form of energy storage in portable electronics is the rechargeable alkali-ion battery, a device that functions entirely on the basis of the reversible transport of alkali ions. The Li+/Na+ conductivity of a cathode has a direct influence on the rate capability of a Li/Na-ion battery, i.e., the speed at which it can be charged and discharged. Alkali conductivity is arguably of even greater importance in the solid electrolytes currently being investigated for high safety, high energy all-solid-state batteries. The research performed in this project has provided critical new insights into the diffusion mechanisms in state-of-the-art alkali superionic conductors such as Li 7 P 3 S 11 , Li 3 OCl 1-x Br x anti-perovskite, argyrodite Li 6 PS 5 Cl. Two potential novel lithium superionic conductors (Li 3 Y(PS 4 ) 2 and Li 5 PS 4 Cl 2 ) with improved electrochemical stabilities were predicted. We have also conducted in-depth studies into alkali conduction in several important classes of electrodes, including the layered P2 NaMO 2 oxides and the highly promising novel disordered rock salt Li 3+x V 2 O 5 anode for high-rate applications. This project has resulted in more than 10 peer-reviewed articles in highly regarded journals as well as a new open-source software framework (pymatgen-analysis-diffusion) that is widely used by the materials research community for the study of diffusion in materials.

25 ENERGY STORAGE↗
DOE OSTI2023

Li 2 GeS 3 : Lithium Ionic Conductor with an Unprecedented Structural Type

Lithium-ion batteries (LIBs) are widely used in electric vehicles, mobile electronic devices, and large-scale stationary energy storage systems. However, their liquid electrolytes present significant safety concerns due to their inherent flammability. To address this, the focus has shifted toward all-solid-state batteries (ASSBs) utilizing inorganic solid electrolytes that promise enhanced safety. In this work, we report the discovery of a new crystal structural type of Li-ion conductor, Li 2 GeS 3 , with a unique structure, synthesized by a solid-state reaction from Li 2 S and GeS 2 . It was first reported in 2000 with an orthorhombic unit cell, but its detailed crystal structure remains veiled. Here, we have unveiled its structure for the first time, employing an ab initio structure determination technique from powder X-ray and time-of-flight neutron diffraction data. The compound has an unprecedented crystal structural type with a hexagonal $P6_1$ symmetry and a unit cell of α = 6.79364(4) Å and c = 17.90724(14) Å. Its structure is comprised of a distorted hexagonal close-packed arrangement of sulfur anions with three asymmetric metal atoms: Li1, Li2, and Ge are in tetrahedral cavities surrounded by sulfur atoms. The ionic conductivity of Li 2 GeS 3 was measured to be 1.63 × 10 –8 S cm –1 at 303 K and 2.45 × 10 –7 S cm –1 at 383 K. Bond valence energy landscape calculations revealed three-dimensional lithium diffusion pathways within the structure. This novel crystal structure in Li 2 GeS 3 holds the potential for developing high-performance ionic conductors through suitable chemical substitution and offers valuable insights into designing new ionic conductors for ASSBs.

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

Materials design of sodium chloride solid electrolytes Na3MCl6 for all-solid-state sodium-ion batteries

All-solid-state sodium-ion batteries have attracted increasing attention owing to the low cost of sodium and the enhanced safety compared to conventional Li-ion batteries. Recently, halides have been considered as promising solid electrolytes (SEs) due to their favorable combination of high ionic conductivity and chemical stability against high-voltage cathode materials. Although a wide variety of lithium chloride SEs, Li 3 MCl 6 , have been developed for high-voltage all-solid-state batteries, only a limited number of sodium chloride SEs have been reported. This study aims to offer a material design insight for the development of sodium chloride SEs through systematic assessment of the phase stability, electrochemical stability, and transport properties of novel Na 3 MCl 6 SEs. Structural calculations indicate that Na 3 MCl 6 exhibits trigonal $P\bar{3}$1c, monoclinic P2 1 /n, and trigonal $R\bar{3}$ phases, and the stable phase of Na 3 MCl 6 is dependent on the type and ionic radius of M. Na 3 MCl 6 typically exhibits a high oxidation potential, demonstrating good electrochemical stability against cathodes. The bond-valence site energy and ab initio molecular dynamics calculations revealed that Na 3 MCl 6 with P2 1 /n and $R\bar{3}$ phases showed low ionic conductivity, while the $P\bar{3}$1c phase slightly improved the ionic conductivity of Na 3 MCl 6 . The formation of Na vacancies by aliovalent substitution considerably increased the ionic conductivity up to four orders of magnitude for pristine Na 3 MCl 6 , exhibiting ~10 –5 S cm –1 for trigonal $P\bar{3}$1c and $R\bar{3}$ phases. The formation of defects could further enhance the ionic conductivity of Na 3 MCl 6 , and the optimization of defect type and ratio can be helpful in developing superionic Na chloride SEs. The material design of Na 3 MCl 6 in this study will provide fundamental guidelines for the development of novel sodium halide SEs for all-solid-state sodium-ion batteries.

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

Li 3.6 In 7 S 11.8 Cl: an air- and moisture-stable superionic conductor

Li 3.6 In 7 S 11.8 Cl has a face-centered cubic arrangement of S 2− /Cl − stabilized by Li + /In 3+ that form 3D ion conduction paths. The moisture stability and fast ion conduction make Li 3.6 In 7 S 11.8 Cl a promising electrolyte for solid-state batteries.

Oyekunle, Ifeoluwa P. [Department of Chemistry and↗
DOE OSTI2026

Four-Dimensional Quasielastic Neutron Scattering (4D-QENS) Analysis of Correlated Ionic Conduction in Sr⁢Cl2

Methods of elucidating the mechanisms of fast-ion conduction in solid-state materials are pivotal for advancements in energy technologies such as batteries, fuel cells, sensors, and supercapacitors. In this study, we examine the ionic conduction pathways in single crystal Sr⁢Cl2, which is a fast-ion conductor above 900 K, using four-dimensional quasielastic neutron scattering (4D-QENS). We explore both coherent and incoherent neutron scattering at temperatures above the transition temperature into the superionic phase to explore the correlated motion of hopping anions. Refinements of the incoherent QENS yield residence times and jump probabilities between lattice sites in good agreement with previous studies, confirming that ionic hopping along nearest-neighbor directions is the most probable conduction pathway. However, the coherent QENS reveals evidence of de Gennes narrowing, indicating the importance of ionic correlations in the conduction mechanism. This highlights the need for improvements both in the theory of ionic transport in fluorite compounds and the modeling of coherent 4D-QENS in single crystals.

Coles, Jared [Materials Science Division, Argonne ↗
DOE OSTI2024

Recent Progress on Dominant Sulfide‐Type Solid‐State Na Superionic Conductors for Solid‐State Sodium Batteries

Abstract Over the past decade, solid‐state batteries have garnered significant attentions due to their potentials to deliver high energy density and excellent safety. Considering the abundant sodium (Na) resources in contrast to lithium (Li), the development of sodium‐based batteries has become increasingly appealing. Sulfide‐based superionic conductors are widely considered as promising solid eletcrolytes (SEs) in solid‐state Na batteries due to the features of high ionic conductivity and cold‐press densification. In recent years, tremendous efforts have been made to investigate sulfide‐based Na‐ion conductors on their synthesis, compositions, conductivity, and the feasibility in batteries. However, there are still several challenges to overcome for their practical applications in high performance solid‐state Na batteries. This article provides a comprehensive update on the synthesis, structure, and properties of three dominant sulfide‐based Na‐ion conductors (Na 3 PS 4 , Na 3 SbS 4 , and Na 11 Sn 2 PS 12 ), and their families that have a variety of anion and cation doping. Additionally, the interface stability of these sulfide electrolytes toward the anode is reviewed, as well as the electrochemical performance of solid‐state Na batteries based on different types of cathode materials (metal sulfides, oxides, and organics). Finally, the perspective and outlook for the development and practical utilization of sulfide‐based SE in solid‐state batteries are discussed.

Guo, Xiaolin↗
DOE OSTI2023

Solvent-free and low temperature synthesis of chalcogenide Na superionic conductors for solid-state batteries

Sodium chalcogenide ionic conductors are attractive candidates as solid electrolytes (SEs) in solid-state Na metal batteries. They show the advantages of high ionic conductivity of 10 –4 –10 –2 S cm –1 at room temperature and great chemical stability in air. However, simple, efficient, and scalable approaches for the synthesis of chalcogenide solid electrolytes (SEs) are required. In this work, we report a solvent-free mixing to form dry intermediate products, which are subjected to different treatments (electron-beam assisted method or low temperature heating (≤150 °C)) to produce pure phase of Na 3 SbS 4-y Se y (0 ≤ y < 2) chalcogenides. Heavy Se-doping in Na 3 SbS 4 results in the tetragonal-to-cubic phase transition as well as a significant change of Sb-S bonding in Raman spectra. Among all chalcogenide SEs, Na 3 SbS 3 Se showed the highest ionic conductivity of 3.75 × 10 –4 S cm –1 at room temperature, 47% higher than that of pristine Na 3 SbS 4 . Moreover, the Se-dopant also enhanced the electrochemical stability towards Na metal in solid-state batteries. The solid-state Na||FeS 2 battery with Na 3 SbS 3 Se SE displayed long-term cycling ability up to 1,000 cycles within the voltage window of 1.0–2.7 V and retained a specific capacity of 105 mAh g –1 after 600 cycles. As a result, this technique promotes the practical applications of chalcogenide SEs in solid-state batteries.

25 ENERGY STORAGE↗
DOE OSTI2025

Li 21 Ge 8 P 3 S 34 : New Lithium Superionic Conductor with Unprecedented Structural Type

Abstract Lithium superionic conductors are pivotal for enabling all‐solid‐state batteries, which aim to replace liquid electrolytes and enhance safety. Herein, we report the discovery of an unprecedented lithium superionic conductor, Li 21 Ge 8 P 3 S 34 , featuring a novel structural type and a new composition in the Li–Ge–P–S system. This material exhibits high lithium ionic conductivity of approximately 1.0 mS cm −1 at 303 K with a low activation energy of 0.20(1) eV. It's unique crystal structure was elucidated using three‐dimensional electron diffraction (3D ED) and further refined through combined powder X‐ray and neutron diffraction analyses. The structure consists of alternating two‐dimensional slabs: one of corner‐sharing GeS 4 tetrahedra and the other of isolated PS 4 tetrahedra, enabling efficient lithium‐ion transport through a tetrahedrally interconnected network of 1D, 2D, and 3D diffusion pathways. This distinctive structural motif provides a novel design strategy for next‐generation solid electrolytes, broadening the structural landscape of lithium superionic conductors. With further advancements in compositional tuning and interfacial engineering, Li 21 Ge 8 P 3 S 34 could contribute to the development of high‐performance all‐solid‐state batteries.

Chemistry↗
DOE OSTI2018

Solid–Liquid Lithium Electrolyte Nanocomposites Derived from Porous Molecular Cages

We demonstrate that solid–liquid nanocomposites derived from porous organic cages are effective lithium ion electrolytes at room temperature. A solid–liquid electrolyte nanocomposite (SLEN) fabricated from a LiTFSI/DME electrolyte system and a porous organic cage exhibits ionic conductivity on the order of 1 × 10 –3 S cm –1 . With an experimentally measured activation barrier of 0.16 eV, this composite is characterized as a superionic conductor. Furthermore, the SLEN displays excellent oxidative stability up to 4.7 V vs Li/Li + . Finally, this simple three-component system enables the rational design of electrolytes from tunable discrete molecular architectures.

25 ENERGY STORAGE↗
DOE OSTI2019

Thermophysical properties of urania-zirconia (U,Zr)O 2 mixed oxides by molecular dynamics

Molecular dynamics simulations were used to investigate the thermophysical properties of (U,Zr)O 2 between 300 K and 3500 K. For compositions with <25% UO 2 the tetragonal phase is stable but beyond 25% the cubic fluorite phase becomes stable for all temperatures. Thermal expansion, heat capacity and thermal conductivity have been predicted. The addition of ZrO 2 to UO 2 causes a reduction in thermal conductivity however this effect decreases with increased temperature and, beyond 1000 K, becomes insignificant. Thermal expansion of (U,Zr)O 2 mixtures with >25% UO 2 , which are in the cubic fluorite phase, is similar to that of the pure UO 2 end member. A superionic transition is observed in cubic (U,Zr)O 2 at temperatures between 1500 K and 3000 K, occurring at progressively lower temperatures with increasing ZrO 2 content. Here, the heat capacity of these mixed oxides increases from 80 J/mol.K up to 130 J/mol.K at temperatures relevant to accident conditions, possibly retarding heating in fuels with a significant pellet-clad bonding layer.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
NASA NTRS1980

Fast ion transport in silver halide solid solutions and multiphase systems

The incorporation of homovalent ions, e.g., I(-) in AgBr, leads to a substantial increase in ionic conductivity sigma. The charge compensation concept does not explain the enhancement. AgBr + 30 mol. % AgI exhibits sigma approximately 7/omega/cm at 380 C, which is approximately 170% larger than that of alpha-AgI, the best known superionic conductor, at its melting point. The purely elastic displacement caused by the foreign ion is suggested to be the origin of such a unique behavior. Furthermore, AgI-AgBr two-phase systems display sigma approximately 10 to the 3rd times higher than predicted by the classical theories.

Shahi, K.↗
DOE OSTI2023

High‐Entropy Lithium Argyrodite Solid Electrolytes Enabling Stable All‐Solid‐State Batteries

Abstract Superionic solid electrolytes (SEs) are essential for bulk‐type solid‐state battery (SSB) applications. Multicomponent SEs are recently attracting attention for their favorable charge‐transport properties, however a thorough understanding of how configurational entropy (ΔS conf ) affects ionic conductivity is lacking. Here, we successfully synthesized a series of halogen‐rich lithium argyrodites with the general formula Li 5.5 PS 4.5 Cl x Br 1.5‐x (0≤x≤1.5). Using neutron powder diffraction and 31 P magic‐angle spinning nuclear magnetic resonance spectroscopy, the S 2− /Cl − /Br − occupancy on the anion sublattice was quantitatively analyzed. We show that disorder positively affects Li‐ion dynamics, leading to a room‐temperature ionic conductivity of 22.7 mS cm −1 (9.6 mS cm −1 in cold‐pressed state) for Li 5.5 PS 4.5 Cl 0.8 Br 0.7 (ΔS conf =1.98R). To the best of our knowledge, this is the first experimental evidence that configurational entropy of the anion sublattice correlates with ion mobility. Our results indicate the possibility of improving ionic conductivity in ceramic ion conductors by tailoring the degree of compositional complexity. Moreover, the Li 5.5 PS 4.5 Cl 0.8 Br 0.7 SE allowed for stable cycling of single‐crystal LiNi 0.9 Co 0.06 Mn 0.04 O 2 (s‐NCM90) composite cathodes in SSB cells, emphasizing that dual‐substituted lithium argyrodites hold great promise in enabling high‐performance electrochemical energy storage.

Chemistry↗
DOE OSTI2026

Mechano-chemical understanding of NaSICON for aqueous redox-flow batteries

Redox-flow batteries utilizing a sodium superionic conductor (NaSICON) can be cost-effective systems for grid energy storage by combining high sodium selectivity with reliance on abundant, low-cost elements. However, improving membrane toughness while maintaining a sufficiently thin membrane for ion conduction is needed. Addressing this issue requires deeper insight into the mechanical properties of NaSICON, its interactions with aqueous chemistries, and the chemo-mechanical degradation mechanisms that arise at the intersection of these phenomena. Here, we provide a framework for understanding these problems, strategies to address them, and highlight the potential of unconventional sintering and thin-film fabrication to optimize the performance of NaSICON in practical flow cells.

Grid energy storage↗
DOE OSTI2020

Abnormally Low Activation Energy in Cubic Na3SbS4 Superionic Conductor

Inorganic Na-ion superionic conductors play a vital role in all-solid-state Na batteries that operate at room temperature. Sodium thioantimonate (Na3SbS4), a popular sulfide-based solid electrolyte, has attracted serious attention due to its advantages of high ionic conductivity at room temperature and impressive chemical stability under ambient conditions. Much research detailing Na3SbS4 focused on its synthetic approaches and interfacial stability against Na metal, yet, there is limited information elucidating a fundamental understanding of the Na- ion diffusion mechanisms in Na3SbS4 with different crystal structures (e.g., tetragonal and cubic). Herein, we combine real-time electrochemical impedance measurements with theoretical simulations based on density functional theory and in situ quasi-elastic neutron scattering to study the Na-ion conductive properties of Na3SbS4 during its phase transition from a tetragonal to cubic structure. Although there is a slight change in the lattice parameters, the energy barrier for Na-ion diffusion in the tetragonal structure was determined to be much larger (5-10 times) than that in the cubic structure from both theoretical and experimental perspectives. The high degree of symmetry in cubic Na3SbS4 leads to less interatomic correlations between Na and S(Sb) atoms, a shorter jump distance (2.85 angstrom), and a larger diffusion coefficient. This research provides insight into understanding the Na-ion diffusion in solid electrolytes with phase transitions and provides fundamental guidance for designing novel solid-state Na-ion conductors.

Zhang, Qian↗
DOE OSTI2021

Visualization of Solid-State Synthesis for Chalcogenide Na Superionic Conductors by in-situ Neutron Diffraction

Chalcogenide superionic sodium (Na) conductors are great potential as solid electrolytes (SEs) in all-solid-state Na batteries with advantages of high energy density and safety, and cost effectiveness. For solid Na-ion conductors, their crystal structures and ionically conductive properties are strongly influenced by the synthetic approaches and processing parameters. Thus, understanding the synthesis process is essential to control the structures and phases and thereby yields to Na-ion conductors with desirable properties. Thanks to the high-flux and deep-penetrating time-of-flight neutron diffraction (ND), we employed in situ experiments to track real-time structural changes of two chalcogenide SEs (Na 3 SbS 4 and Na 3 SbS 3.5 Se 0.5 ) during the solid-state synthesis. For these two conductors, the ND results reveal a fast one-step reaction for the synthesis and the molten process when heating up, and the recrystallization as well as the cubic-to-tetragonal phase transition up on cooling. Moreover, Se-doping is found to influence the reaction temperatures, lattice parameter and structure stability based on neutron experimental observations and theoretical simulation. This work presents a detailed structural study using in situ neutron diffraction technology for the solid synthesis process of chalcogenide Na-ion conductors, beneficial for the design and synthesis of new solid-state conductors.

25 ENERGY STORAGE↗