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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 775 records · Page 43
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Defect Structures of La{sub 1–y}Sr{sub y}F{sub 3–y}, La{sub 1–y}Ba{sub y}F{sub 3–y}, and Nd{sub 1–y}Ca{sub y}F{sub 3–y} (y = 0.05, 0.10) Nonstoichiometric Tysonite Phases

Characteristic features of defect structures of La{sub 1–y}Sr{sub y}F{sub 3–y}, La{sub 1–y}Ba{sub y}F{sub 3–y}, and Nd{sub 1–y}Ca{sub y}F{sub 3–y} (y = 0.05, 0.10) nonstoichiometric phases of different compositions are determined from X-ray diffraction data. Interest in subtle details of their structure is determined by the possibility of ion transport over fluorine vacancies and by a strong compositional dependence of the ionic conductivity. The La{sub 0.95}Sr{sub 0.05}F{sub 2.95}, La{sub 0.95}Ba{sub 0.05}F{sub 2.95}, and Nd{sub 0.95}Ca{sub 0.05}F{sub 2.95} phases, as well as the La{sub 0.9}Ba{sub 0.1}F{sub 2.9} phase, crystallize as β-LaF{sub 3} (sp. gr. P3̅c1, Z = 6). The La{sub 0.9}Sr{sub 0.1}F{sub 2.9} and Nd{sub 0.9}Ca{sub 0.1}F{sub 2.9} phases lose their superstructure and are described by a cell whose volume is three times smaller (sp. gr. P6{sub 3}/mmc, Z = 2). Defects of crystal structure R{sub 1–y}M{sub y}F{sub 3–y} are not exhausted by vacancies in fluorine positions. All crystals with a “large” cell are twinned according to the merohedral twin law. The majority of atomic positions in models with a “small” cell are split by group symmetry elements and are occupied statistically.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2018

Towards Mixed Ionic and Electronic Conducting Li-Stuffed Garnets

Li-stuffed garnet-type Li 7 La 2.75 Ca 0.25 Zr 1.75 Nb 0.25 O 12 (LLCZNO) and Li 7+y La 2.75 Ca 0.25 Zr 1.75-y Nb 0.25 MyO 12 (M = Mn, Fe, Co, Ni; y = 0.1, 0.2, referred to as yM-LLCZNO) were synthesized in air by ceramic synthesis at different sintering temperatures. The resulting compositions were characterized for their phase formation and microstructure, and their ionic and electronic conductivities in air and 7% H 2 /N 2 . Powder X-ray diffraction showed that transition metal-doped LLCZNO garnets contain several impurity phases. The transition metal-substituted samples have lower conductivities than that of the parent LLCZNO. The electronic conductivities of selected transition metal-doped LLCZNO samples were found to be about 4 to 5 orders of magnitude lower than their corresponding ionic conductivity, highlighting the challenge to design single-phase mixed electronic and ionic conducting Li-stuffed garnets in both oxidizing and reducing atmospheres. The research area of single-phase mixed conducting Li-garnet is relatively unexplored at the moment, and a theoretical study will help to elucidate the underlying challenge in doping transition metal in Li-based garnets structure and its effect on transport properties.

25 ENERGY STORAGE↗
DOE OSTI2021

Deep potential generation scheme and simulation protocol for the Li 10 GeP 2 S 12 -type superionic conductors

We report solid-state electrolyte materials with superior lithium ionic conductivities are vital to the next-generation Li-ion batteries. Molecular dynamics could provide atomic scale information to understand the diffusion process of Li-ion in these superionic conductor materials. Here, we implement the deep potential generator to set up an efficient protocol to automatically generate interatomic potentials for Li 10 GeP 2 S 12 -type solid-state electrolyte materials (Li 10 GeP 2 S 12 , Li 10 SiP 2 S 12 , and Li 10 SnP 2 S 12 ). The reliability and accuracy of the fast interatomic potentials are validated. With the potentials, we extend the simulation of the diffusion process to a wide temperature range (300 K–1000 K) and systems with large size (~1000 atoms). Important technical aspects such as the statistical error and size effect are carefully investigated, and benchmark tests including the effect of density functional, thermal expansion, and configurational disorder are performed. The computed data that consider these factors agree well with the experimental results, and we find that the three structures show different behaviors with respect to configurational disorder. Our work paves the way for further research on computation screening of solid-state electrolyte materials.

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

Atomic layer deposited aluminum nitride for interface protection of lithium germanium thiophosphate solid electrolytes

Lithium germanium thiophosphate (LGPS) is an attractive solid-state electrolyte material due to its exceptionally high ionic conductivity (~1.2 × 10 –2 S cm –1 ), comparable to many organic liquid electrolytes commonly used in batteries. Despite the high conductivity of LGPS, the susceptibility of LGPS to deleterious degradation reactions has impeded its commercial adoption into solid-state batteries. In particular, the poor voltage stability of LGPS with high-voltage cathode or lithium metal potentials often results in dramatically increasing cell impedance during galvanic cycling. Here, we use aluminum nitride (AlN) as a protection layer for Li metal anode, applied directly to the LGPS at 250 °C using plasma-enhanced atomic layer deposition, to enhance cell performance by preventing LGPS-Li metal reactions. We compare the surface chemistry and electrochemical cycling performance of atomic layer-deposited AlN grown using both plasma N 2 and NH 3 precursors. Galvanostatic cycling and electrochemical impedance spectroscopy show that AlN-coated LGPS cells perform better than bare LGPS cells in contact with Li metal anodes, with the AlN able to improve cycling longevity by over a factor of 3 in certain cases. Finally, we utilize x-ray photoelectron spectroscopy (XPS) line scans to highlight the slow room-temperature reactivity between AlN and evaporated lithium metal, and a computational model is built to aid further XPS analysis.

25 ENERGY STORAGE↗
DOE OSTI2016

Enhanced performance of dye-sensitized solar cells based on organic dopant incorporated PVDF-HFP/PEO polymer blend electrolyte with g-C{sub 3}N{sub 4}/TiO{sub 2} photoanode

This work describes the effect of 2-aminopyrimidine (2-APY) on poly(vinylidinefluoride-co-hexafluoropropylene) (PVDF-HFP)/polyethylene oxide (PEO) blend polymer electrolyte along with binary iodide salts (tetrabutylammonium iodide (TBAI) and potassium iodide (KI)) and iodine (I{sub 2}) were studied for enhancing the efficiency of the dye-sensitized solar cells (DSSCs) consisting of g-C{sub 3}N{sub 4}/TiO{sub 2} composite as photoanode. The g-C{sub 3}N{sub 4} was synthesized from low cost urea by thermal condensation method. It was used as a precursor to synthesize the various weight percentage ratios (5%, 10% and 15%) of g-C{sub 3}N{sub 4}/TiO{sub 2} composites by wet-impregnation method. The pure and 2-APY incorporated PVDF-HFP/PEO polymer blend electrolytes were arranged by wet chemical process (casting method) using DMF as a solvent. The synthesized g-C{sub 3}N{sub 4}/TiO{sub 2} composites and polymer blend electrolytes were studied and analyzed by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffractometer (XRD) and scanning electron microscopy (SEM). The ionic conductivity values of the pure and 2-APY incorporated PVDF-HFP/PEO blend electrolytes were estimated to be 4.53×10{sup −5} and 1.87×10{sup −4} Scm{sup −1} respectively. The UV–vis absorption spectroscopy was carried out for the pure and different wt% of g-C{sub 3}N{sub 4}/TiO{sub 2} composites coated FTO films after N3 dye-sensitization. The 10 wt% g-C{sub 3}N{sub 4}/TiO{sub 2} composite film showed a maximum absorption compared to the others. The DSSC assembled with 10 wt% g-C{sub 3}N{sub 4}/TiO{sub 2} as photoanode using the pure polymer blend electrolyte exhibited a power conversion efficiency (PCE) of 3.17% , which was superior than that of DSSC based pure TiO{sub 2} (2.46%). However, the PCE was increased to 4.73% for the DSSC assembled using 10 wt% g-C{sub 3}N{sub 4}/TiO{sub 2} as photoanode with 2-APY incorporated polymer blend electrolyte. Hence, the present study is a successful attempt to provide a new pathway to enhance the performance of DSSCs. - Graphical abstract: In this study, the g-C{sub 3}N{sub 4} was synthesized from low cost urea and it was used as a precursor to synthesize of g-C{sub 3}N{sub 4}/TiO{sub 2} composite. The pure and 2-APY incorporated PVDF-HFP/PEO electrolytes were fabricated by solution casting method. A remarkably enhanced PCE of 4.73% was observed for 2-APY incorporated PVDF-HFP/PEO electrolyte with g-C{sub 3}N{sub 4}/TiO{sub 2} composite photoanode based DSSC. - Highlights: • 2-APY added PVDF-HFP/PEO electrolyte was prepared by solution casting method. • The g-C{sub 3}N{sub 4}/TiO{sub 2} composites were synthesized by wet-impregnation method. • DSSC with g-C{sub 3}N{sub 4}/TiO{sub 2} and 2-APY added electrolyte showed the efficiency of 4.73 %. • The g-C{sub 3}N{sub 4} and 2-APY can be a useful dopant to enhance the performance of DSSCs.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2018

Development and Characterization of High Performance and Robust Mixed Conducting Cathodes Supportive of Lower Cost Solid Oxide Fuel Cells (Final Report)

The objective of the proposed research is to advance an existing partnership between the University of South Carolina (USC) and LG Fuel Cell Systems, Inc. (LGFCS) to research and develop mixed electronic and ionic conducting cathode materials for durable and robust low-cost solid oxide fuel cells (SOFCs). The first task is to develop mixed ionic and electronic conducting doped (Pr,Nd)NiO 4 (PNNO)-based cathodes. This task is built on a prior collaborative work with LG Fuel Cell System, which showed that doped PNNO could exhibit phase stability at high temperatures. The initial focus will be on investigating the durability and endurance of its electrochemical performance and the temporal evolution of microstructures. In-situ high temperature neutron diffraction and x-ray diffraction will be used to study the structures of these phase stable compounds. PNNO doped with Ca and transition metal elements will be synthesized. Physical properties of these materials with respect to coefficient of thermal expansion, electrical conductivity, diffusion coefficient, and nonstoichiometry will be measured. The benefits of dense versus porous barriers will be studied and the role of barrier layer will be identified and a guideline will be provided to choose the maximum porosity for durable and robust cathode performance with co-doped PNNO as the cathodes. LSCF6428 will be used to compare its power density with that of co-doped PNNO in the absence of Cr, but some studies comparing Cr tolerance will be performed towards the end of the project. The conditions at which preferred nickelate phases are stable will be defined, including sintering temperature, operating temperature, and composition range. The second task will focus on the investigation of the location of degradation by using differential relaxation time (DRT) analysis, coupled with least squares fitting and systematical post analyses. DRT analysis can provide (1) a direct access to the kinetic parameters of the underlying processes in both cathode and anode, and (2) a clearer picture of SOFC operation, which allows loss factors to the changes of microstructures or activities of either electrode to be distinguished, and a better target fuel cell development to be enabled. The third task aims at applying the accelerated testing protocol to investigate the microstructural evolution of the cathode candidates identified in this research. Technical approaches will be developed to mitigate and improve the durability of cathode materials by choosing the right chemistry and tuning cathode microstructures.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Ion Dynamics in Ionic-Liquid-Based Li-Ion Electrolytes Investigated by Neutron Scattering and Dielectric Spectroscopy

A detailed understanding of the diffusion mechanisms of ions in pure and doped ionic liquids remains an important aspect in the design of new ionic-liquid electrolytes for energy storage. Here, to gain more insight into the widely used imidazolium-based ionic liquids, the relationship between viscosity, ionic conductivity, diffusion coefficients, and reorientational dynamics in the ionic liquid 3-methyl-1-methylimidazolium bis(trifluoromethanesulfonyl)imide (DMIM-TFSI) with and without lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI) was examined. The diffusion coefficients for the DMIM + cation and the role of ion aggregates were investigated by using the quasielastic neutron scattering (QENS) and neutron spin echo techniques. Two diffusion mechanisms are observed for the DMIM + cation with and without Li-TFSI, that is, translational and local. The data additionally suggest that Li + ion transport along with ion aggregates, known as the vehicle mechanism, may play a significant role in the ion diffusion process. These dielectric-spectroscopy investigations in a broad temperature and frequency range reveal a typical α–β-relaxation scenario. The α relaxation mirrors the glassy freezing of the dipolar ions, and the β relaxation exhibits the signatures of a Johari–Goldstein relaxation. In contrast to the translational mode detected by neutron scattering, arising from the decoupled faster motion of the DMIM + ions, the α relaxation is well coupled to the dc charge transport, that is, the average translational motion of all three ion species in the material. Finally, the local diffusion process detected by QENS is only weakly dependent on temperature and viscosity and can be ascribed to the typical fast dynamics of glass-forming liquids.

25 ENERGY STORAGE↗
DOE OSTI2023

Two-dimensional patterning of mesoscale fibers using acoustophoresis

The performance of functional composites can rely critically on the arrangement of secondary phases; for example, patterned networks of conductive particles can impart anisotropic thermal, electric or ionic conductivity while preserving flexibility in the matrix. We demonstrate the use of standing acoustic waves to generate periodic patterns of short fibers. We extend the range of possible patterns with the first demonstration of both rectangular grids and arrays of octagons interspersed with rectangles. These newly demonstrated patterns are rationalized using theoretical models of acoustic forces and torques on fibers that account for two-dimensional spatial variations arising from applied acoustic fields. The models enable simulations of fiber motion, which are used to (i) map out final fiber positions as a function of initial position and orientation, and (ii) corroborate experiments visualizing fiber motion and final patterns. This approach provides a fast and accurate way to predict emergent fiber patterns as a function of excitation modality and fiber length. The theory and experiments clearly indicate strong coupling between the length of the fibers and the spacing of the acoustic nodes. Furthermore, this coupling is used to estimate reductions in percolation thresholds associated with the ratio of fiber length and acoustic wavelength.

25 ENERGY STORAGE↗
DOE OSTI2023

Advancing ionomer design to boost interfacial and thin-film proton conductivity via styrene-calix[4]arene-based ionomers

Sub-micrometer-thick ion-conducting polymer (ionomer) layers often suffer from poor ionic conductivity at the substrate/catalyst interface. The weak proton conductivity makes the electrochemical reaction at the cathode of proton-exchange-membrane fuel cells sluggish. To address this, here we report on a class of polystyrene-based ionomers having sub-nanometer-sized, sulfonated macrocyclic calix[4]arene-based pendants (PS-calix). In films with thickness comparable to that of ionomer-based binder layers, the conductivity of PS-calix film (~41 mS/cm) is ~13 times higher than that of the current state-of-the-art ionomer, Nafion. We observe a similar improvement in proton conductivity when PS-calix interfaces with Pt nanoparticles, demonstrating the potential of PS-calix in catalyst ink. Leveraging a favorable interfacial chemical composition, PS-calix enhances proton conduction at the film-substrate interface, a shortcoming of Nafion. Moreover, the water in PS-calix films diffuses faster than bulk water and the water confined in Nafion films, suggesting an important role played by sub-nanometer-sized calix[4]arene cavities in creating unique water/ion transport pathways.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Solid-State, Single-Ion Conducting, Polymer Blend Electrolytes with Enhanced Li + Conduction, Electrochemical Stability, and Limiting Current Density

The development of solid-state polymer electrolytes with high lithium conductivity is crucial to improve lithium-ion battery performance and ameliorate the safety challenges associated with current solvent-based electrolytes. Unfortunately, sluggish polymer segmental dynamics are known to constrain conductivity enhancements in solid-state polymer electrolyte systems, limiting overall performance. In this work, a glassy single-ion-conducting polymer, poly[lithium sulfonyl(trifluoromethane sulfonyl)imide methacrylate] (PLiMTFSI), was blended with a flexible polymer, poly(oligo-oxyethylene methyl ether methacrylate) (POEM), and the impact of PLiMTFSI molecular weight and ion concentration on the thermal and ion-conducting behavior of blend electrolytes was investigated. High ionic conductivities approaching 1 × 10 -2 S/cm at 150 °C were realized in this polymer blend electrolyte system as a result of decoupling Li + transport from polymer segmental dynamics. The decoupled ion transport was attributed to the packing frustration of the glassy PLiMTFSI – sufficient percolating free volume was generated to produce effective ion diffusion pathways. This decoupling was tunable as the ion transport could be altered from being closely coupled to the polymer segmental dynamics (Vogel–Tammann–Fulcher-like) to hopping (Arrhenius-like) by increasing the PLiMTFSI molecular weight and ion concentration. Moreover, the immobilized TFSI anion resulted in high Li + selectivity (Li + transference number = 0.9), high electrochemical stability (up to 4.7 V against Li + / Li), and limiting current density of 1.8 mA/cm 2 (electrolyte thickness = 0.05 cm). These features suggest that this single-ion-conducting, polymer blend electrolyte might be a promising alternative to a benchmark system – salt-doped polyethylene oxide. Moreover, the above characteristics can support the battery operation at higher voltages using energy-dense Li metal anodes, with faster charging rates and enhanced energy/power densities. Altogether, the results suggest that polymer chain packing frustration can be exploited to overcome the constraints of slow polymer segmental relaxations to achieve rapid and highly selective ion transport and enhanced performance in solid-state polymer electrolytes.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Methods for hydrogen gas production through water electrolysis

A method of producing hydrogen gas comprises introducing gaseous water to an electrolysis cell comprising a positive electrode, a negative electrode, and a proton conducting membrane between the positive electrode and the negative electrode. The proton conducting membrane comprises an electrolyte material having an ionic conductivity greater than or equal to about 10−2 S/cm at one or more temperatures within a range of from about 150° C. to about 650° C. The gaseous water is decomposed using the electrolysis cell. A hydrogen gas production system and an electrolysis cell are also described.

He, Ting↗
DOE OSTI2022

Methods for carbon dioxide hydrogenation

A method of carbon dioxide hydrogenation comprises introducing gaseous water to a positive electrode of an electrolysis cell comprising the positive electrode, a negative electrode, and a proton-conducting membrane between the positive electrode and the negative electrode. The proton-conducting membrane comprises an electrolyte material having an ionic conductivity greater than or equal to about 10-2 S/cm at one or more temperatures within a range of from about 150° C. to about 650° C. Carbon dioxide is introduced to the negative electrode of the electrolysis cell. A potential difference is applied between the positive electrode and the negative electrode of the electrolysis cell to generate hydrogen ions from the gaseous water that diffuses through the proton-conducting membrane and hydrogenates the carbon dioxide at the negative electrode. A carbon dioxide hydrogenation system is also described.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Methods for producing hydrocarbon products and protonation products through electrochemical activation of ethane

A method of forming a hydrocarbon product and a protonation product comprises introducing C2H6 to a positive electrode of an electrochemical cell comprising the positive electrode, a negative electrode, and a proton-conducting membrane between the positive electrode and the negative electrode. The proton-conducting membrane comprises an electrolyte material having an ionic conductivity greater than or equal to about 10−2 S/cm at one or more temperatures within a range of from about 150° C. to about 650° C. A potential difference is applied between the positive electrode and the negative electrode of the electrochemical cell to produce the hydrocarbon product and the protonation product. A C2H6 activation system and an electrochemical cell are also described.

He, Ting↗
DOE OSTI2023

Methods for producing hydrocarbon products and hydrogen gas through electrochemical activation of methane

A method of forming a hydrocarbon product and hydrogen gas comprises introducing CH 4 to a positive electrode of an electrochemical cell comprising the positive electrode, a negative electrode, and a proton-conducting membrane between the positive electrode and the negative electrode. The proton-conducting membrane comprises an electrolyte material having an ionic conductivity greater than or equal to about 10 −2 S/cm at one or more temperatures within a range of from about 150° C. to about 600° C. A potential difference is applied between the positive electrode and the negative electrode of the electrochemical cell to produce the hydrocarbon product and the hydrogen gas. A CH 4 activation system and an electrochemical cell are also described.

Ding, Dong↗
DOE OSTI2023

Methods for co-producing hydrocarbon products and ammonia

A method of a hydrocarbon product and ammonia comprises introducing C 2 H 6 to a positive electrode of an electrochemical cell comprising the positive electrode, a negative electrode, and a proton-conducting membrane between the positive electrode and the negative electrode. The proton-conducting membrane comprising an electrolyte material having an ionic conductivity greater than or equal to about 10 −2 S/cm at one or more temperatures within a range of from about 150° C. to about 600° C. N 2 is introduced to the negative electrode of the electrochemical cell. A potential difference is applied between the positive electrode and the negative electrode of the electrochemical cell. A system for co-producing higher hydrocarbons and NH3, and an electrochemical cell are also described.

Ding, Dong↗
DOE OSTI2023

Proton-controlled molecular ionic ferroelectrics

Abstract Molecular ferroelectric materials consist of organic and inorganic ions held together by hydrogen bonds, electrostatic forces, and van der Waals interactions. However, ionically tailored multifunctionality in molecular ferroelectrics has been a missing component despite of their peculiar stimuli-responsive structure and building blocks. Here we report molecular ionic ferroelectrics exhibiting the coexistence of room-temperature ionic conductivity (6.1 × 10 −5 S/cm) and ferroelectricity, which triggers the ionic-coupled ferroelectric properties. Such ionic ferroelectrics with the absorbed water molecules further present the controlled tunability in polarization from 0.68 to 1.39 μC/cm 2 , thermal conductivity by 13% and electrical resistivity by 86% due to the proton transfer in an ionic lattice under external stimuli. These findings enlighten the development of molecular ionic ferroelectrics towards multifunctionality.

42 ENGINEERING↗
DOE OSTI2019

Electrochemical performance and stability of SrTi 0.3 Fe 0.6 Co 0.1 O 3-δ infiltrated La 0.8 Sr 0.2 MnO 3 Zr 0.92 Y 0.16 O 2-δ oxygen electrodes for intermediate-temperature solid oxide electrochemical cells

We report that the La 0.8 Sr 0.2 MnO 3 -Zr 0.92 Y 0.16 O 2-δ (LSM-YSZ) composite is the most widely used oxygen electrode for solid oxide electrochemical cells (SOCs). However, operating temperatures > 700 degrees C are required for good performance since oxygen reactions are limitied to three-phase boundaries (TPBs) because of poor ionic conductivity of LSM. Furthermore, LSM-YSZ electrodes typically delaminate during electrolysis operation leading to cell degradation. One strategy to improve SOCs with LSM-YSZ electrodes is to infiltrate a mixed ionically and electronically conducting (MIEC) material that promotes oxygen exchange. However, infiltrated materials have a nano-scale structure that may not be stable under SOC operating temperatures. Here, we report results on the infiltration of SrTi 0.3 Fe 0.6 Co 0.1 O 3-δ (STFC), a recently reported high performance MIEC, into LSM-YSZ to improve its electrochemical performance and stability at intermediate temperatures. The infiltrated STFC enhances LSM-YSZ and cell performance, typically yielding a decrease in electrode polarization resistance by a factor > 3 times, resulting in an increase in fuel cell maximum power density and electrolysis current density (at 1.3 V) by a factor > 2 times. Perhaps more significantly, the infiltrated electrodes show good performance stability, with suppression of electrode delamination during electrolysis and no evidence of coarsening or segregation induced degradation.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Influence of a platinum functional layer on a Ni-Ce{sub 0.9}Gd{sub 0.1}O{sub 1.95} anode for thin-film solid oxide fuel cells

A Pt functional layer was deposited between a Ni-Ce{sub 0.9}Gd{sub 0.1}O{sub 1.95} (50 wt. % Ni) anode and an 8 mol. % yttria-stabilized zirconia electrolyte in order to enhance the performance of a thin film solid oxide fuel cell. By inserting this ultrathin functional layer, the ohmic impedance of the single cell was significantly reduced, and the maximum power density was increased by a factor of ∼1.55. However, excessive deposition of the Pt functional layer caused ionic conduction pathway blocking between the yttria-stabilized zirconia and Ni-Gd{sub 0.1}Ce{sub 0.9}O{sub 1.95} (Ni-GDC), deactivating the Ni-GDC as a mixed ionic and electronic conducting anode. As a result, both the ohmic impedance and anodic faradaic impedance were increased after introduction of excessive Pt functional layer, and the maximum power density was also reduced.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗