The oxygen partial pressure in solid oxide electrolysis cells with multilayer electrolytes
Not provided.
Materials Science↗
SEARCH · Engineering Papers
Results for “oxide solid electrolyte”
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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Atomic insights into the oxidative degradation mechanisms of sulfide solid electrolytes
Not Available
25 ENERGY STORAGE↗
High lithium oxide prevalence in the lithium solid–electrolyte interphase for high Coulombic efficiency
Not provided.
Energy & Fuels↗
Next Generation Durable, Cost Effective, Energy Efficient Tubular SOFC (Final Scientific/Technical Report)
The overall objective of this project is to develop and optimize a YSZ electrolyte-based solid oxide fuel cell (SOFC) technology for low cost, low temperature (~ 650°C), and high energy efficiency operation. The developed technology will be implemented and demonstrated in a high efficiency 2~3kW SOFC with applicability to sub-MW systems. A summary of significant accomplishments is provided below. Key accomplishments: 1. Improved fundamental cell technology demonstrated at single tube and system scale. Improved power output by 54% while operating at the normal temperature of 750°C. And improved power output by 33% while operating at 650°C, 100°C lower than normal temperature. 2. SPS patented internal recycle arrangement was developed and extended to operate on LPG fuel directly in a compact, high-efficiency (> 40%) system. 3. System testing was conducted to prove the long-term durability of cell improvements. Demonstrated over 8000 hours of operation at 0.21 %/1000 hrs degradation. 4. A large-scale, 2.5kW net power system demonstration was completed, which demonstrated 40% net efficiency over 1000 hours. 5. System design and cost analysis of a 1MW system utilizing a 2.5kW bundle was completed. Cost optimization of the bundle showed a reduction of nearly 80% is possible from $\$$5,790/kW to $\$$1250/kW. This lower cost is considered viable for SPS commercialization.
03 NATURAL GAS↗
Determining the Source of Water Vapor in a Cerium Oxide Electrochemical Oxygen Separator to Achieve Aviator Grade Oxygen
More than a metric ton of water is transported to the International Space Station (ISS) each year to provide breathing oxygen for the astronauts. Water is a safe and compact form of stored oxygen. The water is electrolyzed on ISS and ambient pressure oxygen is delivered to the cabin. A much smaller amount of oxygen is used each year in spacesuits to conduct Extra Vehicular Activities (EVAs). Space suits need high pressure (>1000 psia) high purity oxygen (must meet Aviator Breathing Oxygen "ABO" specifications, >99.5% O2). The water / water electrolysis system cannot directly provide high pressure, high purity oxygen, so oxygen for EVAs is transported to ISS in high pressure gas tanks. The tanks are relatively large and heavy, and the majority of the system launch weight is for the tanks and not the oxygen. Extracting high purity oxygen from cabin air and mechanically compressing the oxygen might enable on-board production of EVA grade oxygen using the existing water / water electrolysis system. This capability might also benefit human spaceflight missions, where oxygen for EVAs could be stored in the form of water, and converted into high pressure oxygen on-demand. Cerium oxide solid electrolyte-based ion transport membranes have been shown to separate oxygen from air, and a supported monolithic wafer form of the CeO2 electrolyte membrane has been shown to deliver oxygen at pressures greater than 300 psia. These supported monolithic wafers can withstand high pressure differentials even though the membrane is very thin, because the ion transport membrane is supported on both sides (Fig 1). The monolithic supported wafers have six distinct layers, each with matched coefficients of thermal expansion. The wafers are assembled into a cell stack which allows easy air flow across the wafers, uniform current distribution, and uniform current density (Fig 2). The oxygen separation is reported to be "infinitely selective" to oxygen [1] with reported purity of 99.99% [2]. Combined with a mechanical compressor, a Solid Electrolyte Oxygen Separator (SEOS) should be capable of producing ABO grade oxygen at pressures >2400 psia, on the space station. Feasibility tests using a SEOS integrated with a mechanical compressor identified an unexpected contaminant in the oxygen: water vapour was found in the oxygen product, sometimes at concentrations higher than 40 ppm (the ABO limit for water vapour is 7 ppm). If solid electrolyte membranes are really "infinitely selective" to oxygen as they are reported to be, where did the water come from? If water is getting into the oxygen, what other contaminants might get into the oxygen? Microscopic analyses of wafers, welds, and oxygen delivery tubes were performed in an attempt to find the source of the water vapour contamination. Hot and cold pressure decay tests were performed. Measurements of water vapour as a function of O2 delivery rate, O2 delivery pressure, and process air humidity levels were the most instructive in finding the source of water contamination (Fig 3). Water contamination was directly affected by oxygen delivery rate (doubling the oxygen production rate cut the water level in half). Water was affected by process air humidity levels and delivery pressure in a way that indicates the water was diffusing into the oxygen delivery system.
Graf, John↗
Achieving American Leadership in the Hydrogen Supply Chain Factsheet
Hydrogen has been identified as a key energy option to enable full decarbonization of the energy system. A secure, resilient supply chain will be critical to achieving emissions reductions and capturing the economic opportunity inherent in the energy sector transition. Electrolyzers and fuel cells are two critical components of the hydrogen supply chain that today are largely nascent industries with limited data on supply chain needs and constraints. This fact sheet summarizes findings from an accompanying report that is one in a series of deep dive assessments of the energy industrial base called for in Executive Order 14017 on America’s supply chains. The report identifies key considerations for the development of water electrolyzer and fuel cell supply chains and materials, focusing on polymer electrolyte and solid oxide technologies, to meet future demand for hydrogen produced by electrolysis and achieve U.S. decarbonization goals.
Source record↗
Composite Solid Electrolyte for Li Battery Applications
The electrochemical, bulk and interfacial properties of the polyethylene oxide (PEO) based composite solid electrolyte (CSE) comprising LiI, PEO, and Al2O3 have been evaluated for Li battery applications. The bulk interfacial and transport properties of the CSEs seem to strongly depend on the alumina particle size. For the CSE films with 0.05 micron alumina while the bulk conductivity is around 10(exp -4) (mho/cm) at 103 C, the Li ion transport number seems to be close to unity at the same temperature. Compared to the PEO electrolyte this polymer composite electrolyte seems to exhibit robust mechanical and interfacial properties. We have studied three different films with three different alumina sizes in the range 0.01-0.3 micron. Effects of Al2O3 particle size on the electrochemical performance of polymer composite electrolyte is discussed. With TiS2 as cathode a 10 mAh small capacity cell was charged and discharged at C/40 and C/20 rates respectively.
Nagasubramanian, G.↗
Deep eutectic solvent-based polymer electrolyte for solid-state lithium metal batteries
Poly(ethylene) oxide (PEO)-based electrolytes have been widely studied for solid-state lithium batteries while their ionic conductivity and lithium-ion transference number still need to be further improved. Herein, using the combined experimental and theoretical approach, we demonstrate a novel, solid-state PEO-deep eutectic solvent (DES) electrolyte for the first time. We found that the in situ formation of DES can reduce the crystallinity of PEO matrix and more Li + ions can move freely owing to the weakened coordination between ether oxygens and Li-ions. Besides, we show that more Li + ions can be dissociated from Li salts in PEO-DES electrolyte using the molecular dynamics simulations. Such liquid-free PEO-DES electrolytes showed good ionic conductivity (2.1 × 10 −4 S cm −1 ) which is 160% higher than that of conventional PEO-LiTFSI (8.1 × 10 −5 S cm −1 ) electrolyte at 60 °C. Additionally, the PEO-DES electrolyte showed 136% increase of Li-ion transference number (0.33) compared with ionic liquid-doped PEO-LiTFSI (0.14) at 60 °C. Moreover, the PEO-DES exhibited good compatibility with Li metal and stable Li plating/stripping behavior with little morphology change of Li metal. In conclusion, this research also provides new insights into the enhancement mechanisms of novel polymer electrolytes, improving our fundamental understanding of critical challenges that have impeded the adoption of solid-state lithium metal batteries.
Deep eutectic solvent↗
Design principles for anode stable solid-state electrolytes
This work presents a comparative study of six types of oxide and halide solid-state electrolytes. It has been demonstrated that the electrochemical stability not only depends on metal species, but alsk the Li content and other factors.
Chemistry↗
All-Solid-State Lithium–Sulfur Batteries Enhanced by Redox Mediators
We report redox mediators (RMs) play a vital role in some liquid electrolyte-based electrochemical energy storage systems. However, the concept of redox mediator in solid-state batteries remains unexplored. Here, we selected a group of RM candidates and investigated their behaviors and roles in all-solid-state lithium-sulfur batteries (ASSLSBs). The soluble-type quinone-based RM (AQT) shows the most favorable redox potential and the best redox reversibility that functions well for lithium sulfide (Li 2 S) oxidation in solid polymer electrolytes. Accordingly, Li 2 S cathodes with AQT RMs present a significantly reduced energy barrier (average oxidation potential of 2.4 V) during initial charging at 0.1 C at 60 °C and the following discharge capacity of 1133 mAh g s -1 . Using operando sulfur K-edge X-ray absorption spectroscopy, we directly tracked the sulfur speciation in ASSLSBs and proved that the solid-polysulfide-solid reaction of Li 2 S cathodes with RMs facilitated Li 2 S oxidation. In contrast, for bare Li 2 S cathodes, the solid-solid Li 2 S-sulfur direct conversion in the first charge cycle results in a high energy barrier for activation (charge to ~4 V) and low sulfur utilization. The Li 2 S@AQT cell demonstrates superior cycling stability (average Coulombic efficiency 98.9% for 150 cycles) and rate capability owing to the effective AQT-enhanced Li-S reaction kinetics. This work reveals the evolution of sulfur species in ASSLSBs and realizes the fast Li-S reaction kinetics by designing an effective sulfur speciation pathway
25 ENERGY STORAGE↗
Avoiding CO 2 Improves Thermal Stability at the Interface of Li 7 La 3 Zr 2 O 12 Electrolyte with Layered Oxide Cathodes
Abstract Solid‐state batteries promise higher energy densities and better safety than Li‐ion batteries with liquid electrolytes. However, the interface between solid electrolyte and cathode is unstable at the elevated temperatures that are needed while sintering to achieve good bonding between ceramic components. Here, the hypothesis is that, the gas environment, especially the presence of CO 2, is critical in determining the stability of the solid electrolyte–cathode interface. The effect of gas species on the interface is systematically probed, by a using Li 7 La 3 Zr 2 O 12 (LLZO) solid electrolyte with a thin film LiNi 0.6 Mn 0.2 Co 0.2 O 2 cathode as a model system to enable interface sensitivity. Detrimental phases formed at the interface and their onset conditions are identified by X‐ray absorption spectroscopy, X‐ray diffraction, and Gibbs free energy analysis. As a result, removing CO 2 and minimizing H 2 O(g) during sintering is necessary to obtain good contact at the LLZO|cathode interface without forming secondary phases. Sintering in O 2 is ideal, yielding excellent chemical stability and low interfacial resistance. Secondary phases also do not form in N 2, but oxygen loss occurs at elevated temperatures. The interfacial resistance obtained upon sintering in pure O 2 is comparable to the lowest values at LLZO interfaces with protective coatings, but here without the need for interface coatings.
25 ENERGY STORAGE↗
A room temperature rechargeable Li 2 O-based lithium-air battery enabled by a solid electrolyte
Lithium-air batteries have scope to compete with gasoline in terms of energy density. However, in most systems, the reaction pathways either involve one- or two-electron transfer, leading to lithium peroxide (Li 2 O 2 ) or lithium superoxide (LiO 2 ), respectively. Kondori et al. investigated a lithium-air battery that uses a ceramic-polyethylene oxide–based composite solid electrolyte and found that it can undergo a four-electron redox reaction through lithium oxide (Li 2 O) formation and decomposition (see the Perspective by Dong and Lu). The composite electrolyte embedded with Li 10 GeP 2 S 12 nanoparticles shows high ionic conductivity and stability and high cycle stability through a four-electron transfer process.
25 ENERGY STORAGE↗
Effect of Propagating Dopant Reactivity on Lattice Oxygen Loss in LLZO Solid Electrolyte Contacted with Lithium Metal
Lithium lanthanum zirconium oxide (LLZO) is widely known as the most stable solid electrolyte against lithium metal electrodes. This thermodynamic stability can be lost by the presence of dopants which are required to stabilize the cubic phase of LLZO and can be reduced by lithium metal. However, the role of oxygen in such reactions is taken for granted. In this work, the reduction of Nb-substituted LLZO (Nb-LLZO) is explored by Li metal and shows that interfacial reactions propagate and lead to the decomposition with substantial Nb 5+ reduction deep into the bulk electrolyte. Scanning Transmission Electron Microscopy with Energy Dispersive X-ray Spectroscopy and thermogravimetric analyses show much of the reduction is due to oxygen vacancies formed, leading to increased electronic conductivity mapped with conductive Atomic Force Microscopy. Density functional theory calculations indicate oxygen release is favored by increased excess lithiation of Nb-LLZO. Electrochemical impedance of polycrystalline Nb-LLZO shows the continuous evolution of ionically resistive interphases near the lithium metal interface with Nb-LLZO while single crystals show little reactivity at room temperature and self-limiting reduction at 60°C. This work underlines the role of grain boundaries in propagating destructive solid electrolyte reactions and highlights previously unseen mechanisms involving lattice oxygen in LLZO.
Li metal, solid-state electrolytes↗
Exploring the Ion Solvation Environments in Solid-State Polymer Electrolytes through Free-Energy Sampling
The success of poly(ethylene oxide) (PEO) in solid-state polymer electrolytes for lithium-ion batteries is well established. Recently, in order to understand this success and to explore possible alternatives, we studied polyacetal electrolytes to deepen the understanding of the effect of the local chemical structure on ion transport. Advanced molecular dynamics techniques using newly developed, tailored interaction potentials have helped elucidate the various coordination environments of ions in these systems. In particular, the competition between cation-Anion pairing and coordination by the polymer has been explored using free-energy sampling (metadynamics). At equivalent reduced temperatures, with respect to the polymer-specific glass-Transition temperature, two-dimensional free-energy plots reveal the existence of multiple coordination environments for the lithium (Li) ions in these systems and their relative stabilities. Furthermore, we observe that the Li-ion movement in PEO follows a serial, stepwise pathway when moving from one coordination state to another, whereas this happens in a more continuous and concerted fashion in a polyacetal such as poly(1,3-dioxalane) [P(EO-MO)]. The implication is that interconversion between coordination states of the Li ions may be easier in P(EO-MO). However, the overarching observation from our free-energy analysis is that Li-ion coordination is dominated by the polymer (in either case) and contact-ion pairs are rare. We rationalize the observed higher increase in glass-Transition temperature (Tg) with salt loading in polyacetals as due to intermolecular Li-ion coordination involving multiple polymer chains, rather than just one chain for PEO-based electrolytes. This interchain coupling in the polyacetals, resulting in the higher Tg, works against any gains due to variations in Li-ion coordination that might enhance transport processes over PEO. Further research is required to overcome the interdependence between local coordination and macroscopic properties to compete with PEO electrolytes at the same absolute working temperature.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Alkaline manganese redox flow battery with inhibitor
A redox flow battery includes a redox flow cell and a supply and storage system external of the redox flow cell. The supply and storage system includes first and second electrolytes for circulation through the redox flow cell. The first electrolyte is a liquid electrolyte having electrochemically active manganese species with multiple, reversible oxidation states in the redox flow cell. The electrochemically active manganese species may undergo reactions that cause precipitation of manganese oxide solids. The first electrolyte includes an inhibitor that limits the self-discharge reactions. The inhibitor includes an oxoanion compound.
Davenport, Timothy↗
Creep Resistance of ZrO2 Ceramic Improved by the Addition of a Small Amount of Er2O3
Zirconia (ZrO2) has great technological importance in structural, electrical, and chemical applications. It is the crucial component for state-of-the art thermal barrier coatings and an enabling component as a solid electrolyte for solid-oxide fuel cell systems. Pure ZrO2 is of limited use for industrial applications because of the phase transformations that occur. Upon the addition of stabilizers, cubic (c-ZrO2) and tetragonal (t-ZrO2) forms can be preserved. It is the stabilized and partially stabilized forms of zirconia that function as thermal barrier coatings, solid electrolytes, and oxygen sensors and that have numerous applications in the electrochemical industry. The cubic form of ZrO2 is typically stabilized through Y2O3 additions. However, Y2O3-stabilized zirconia is susceptible to deformation at high temperatures (greater than 900 C) because of the large number of slip systems and the high oxygen diffusion rates, which result in high creep rates at high temperatures. Successful use of ZrO2 at high temperatures requires that new dopant additives be found that will retain or enhance the desirable properties of cubic ZrO2 and yet produce a material with lower creep rates. At the NASA Glenn Research Center, erbium oxide (Er2O3) was identified as a promising dopant for improving the creep resistance of. ZrO2. The selection of Er2O3 was based on the strong interactions of point defects and dislocations. Single crystals of 5 mol% Er2O3- doped ZrO2 rods (4 mm in diameter) and monofilaments (200 to 300 mm in diameter and 30 cm long) were grown using the laser-heated float zone technique, and their creep behavior was measured as a function of temperature. The addition of 5 mol% Er2O3 to single-crystal ZrO2 improved its creep resistance at high temperatures by 2 to 3 orders of magnitude over state-of-the-art Y2O3-doped crystals. Detailed microstructural characterization of ZrO2-Er2O3 single crystals has identified new mechanisms for improving the creep resistance of this class of materials. Adding Er2O3 to ZrO2 results in microstructure of stable and metastable tetragonal precipitates that with thermal treatment evolve to a tweed structure of nanosize tetragonal lamellae. The superior high-temperature creep resistance of Er2O3-doped ZrO2 is attributed to nanoscale precipitation hardening. Doping with Er2O3 will significantly increase the upper-use temperature limit of ZrO2. Potential applications include using Er2O3-doped ZrO2 as a high-temperature fiber for structural applications and adding Er2O3 to reduce the sintering rates of ZrO2 thermal barrier coatings. This work was conducted at Dpto. de F sica de la Materia Condensada, Universidad de Sevilla, Spain, and at NASA Glenn.
Martinez-Fernandez, Julian↗
Phase Morphology Dependence of Ionic Conductivity and Oxidative Stability in Fluorinated Ether Solid-State Electrolytes
Not Available
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗