Article
Chemistry, Physical
Aarthi Uthayakumar, M. Kavithanjali, K. Sandhya, N. Ponpandian, K. Suresh Babu
Summary: Introducing trivalent rare-earth dopants in barium cerate-zirconate solid solution can modulate grain boundary resistance and enhance protonic conductivity. Doping with smaller ionic radii allows for lower proton trapping sites, achieving higher conductivity.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Physical
X. Y. Ping, B. Meng, W. K. Liang, Q. Zheng, C. Li
Summary: In this study, composite powders of Ce0.85Y0.15O2-delta (YDC)-xmol% aluminum compound were prepared by mixing YDC with different amounts of Al(NO3)(3) and densified through spark plasma sintering. The formation of CeAlO3 phase and reduction in grain size were observed with increasing Al(NO3)(3) addition amount. While the presence of CeAlO3 phase in A10 and A20 samples decreased the grain boundary conductivity, the evenly distributed CeAlO3 grains in A40 led to a significant increase in grain boundary conductivity.
SOLID STATE IONICS
(2021)
Article
Chemistry, Physical
Grazia Accardo, Emilio Audasso, Sung Pil Yoon
Summary: Microstructural and electrochemical investigations were conducted on tri-doped cerium oxide with Gd, Li, and Bi. The combination of lithium and bismuth effectively reduced the sintering temperature. The doping-induced complex network of defects improved the ionic transport and increased the total conductivity.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Physical
Takuya Yamaguchi, Tomohiro Ishiyama, Haruo Kishimoto, Katherine Develos-Bagarinao, Katsuhiko Yamaji
Summary: The deuteron solubilities in 8YSZ and 10GDC polycrystals increase with increasing grain boundary densities and decreasing temperature, showing an opposite relationship with D2O vapor pressure. Deuterons are mainly incorporated into grain boundaries through the reaction of D2O vapor with oxygen vacancies, but the expected linear relationship between solubilities and p(D2O)(1/2) was not observed. This discrepancy is attributed to the existence of two types of deuterons with different incorporation energies at the grain boundaries.
SOLID STATE IONICS
(2022)
Article
Electrochemistry
Prerna Vinchhi, Roma Patel, Indrajit Mukhopadhyay, Abhijit Ray, Ranjan Pati
Summary: This study investigates the impact of Sm3+ doping concentration on the grain boundary ionic conductivity of ceria. Materials were prepared using a modified co-precipitation method and sintered at high temperature to achieve highly dense pellets. Structural analyses confirmed the single phase cubic structure of samaria doped ceria (SDC) nanoparticles, and the ionic conductivity measurements showed superior grain boundary conductivity for certain compositions.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2021)
Article
Chemistry, Physical
Kerstin Neuhaus, Hans-Dieter Wiemhoefer
Summary: This study evaluated the influence of different concentrations of Al2O3 addition on the electrochemical characteristics of ceria and Gd-doped ceria samples. The results showed that the addition of Al2O3 altered the distribution of Volta potential at grain boundaries, leading to an increased potential difference between bulk and grain boundary cores, as well as a broadening of the potential gradient at the grain boundaries.
SOLID STATE IONICS
(2021)
Article
Chemistry, Physical
Takuya Yamaguchi, Tomohiro Ishiyama, Haruo Kishimoto, Katherine Develos-Bagarinao, Katsuhiko Yamaji
Summary: Deuteron distribution in polycrystalline 10GDC was examined using NanoSIMS, revealing deuteron dissolution mainly at grain boundaries. The enrichment of Gd at grain boundaries was observed, prompting an investigation of the effect of Gd concentration on deuteron solubility. The study found that as Gd concentration increased, the bulk deuteron solubility significantly increased, suggesting that Gd enrichment contributes to the high solubility of protons/deuterons at grain boundaries. The enhanced solubility can be attributed to the higher oxygen basicity resulting from the lower electronegativity of Gd3+ compared to Ce4+.
SOLID STATE IONICS
(2023)
Article
Chemistry, Physical
Ekaterina Antonova, Evgeniy Tropin, Anna Khodimchuk
Summary: La2-xSrxZr2O7-delta oxides were synthesized using the citrate-nitrate method, with the solubility limit for strontium in La2Zr2O7 found to be 0.07. A second phase of SrZrO3 was observed at higher strontium content. The conductivity of the electrolyte in wet air was higher than in dry air, with Sr-doped oxides showing a more pronounced response.
Article
Chemistry, Multidisciplinary
Philipp Simons, Kierstin P. Torres, Jennifer L. M. Rupp
Summary: This study found that sprayed ceria thin films exhibit proton conductivity at low temperatures, with post-annealing enhancing conductivity due to improved crystallinity and grain size. The slow hydration kinetics of ceria may have suppressed proton conduction in previous studies, leading to fluctuations in reports. It is important to consider the slow protonation kinetics when designing functional ceria ceramics for various applications.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Engineering, Chemical
Lujian Jia, Mengke Liu, Xia Xu, Weichao Dong, Heqing Jiang
Summary: By doping Gd-doped ceria (CGO) with excellent oxygen ionic conductivity into Sr-based hydrogen separation membranes, a novel triple-conducting (H+/O2-/e(-)) membrane, Ce0.90Gd0.10O3-delta-SrCe0.95Fe0.05O3 (-delta)-SrFe0.95Ce0.05O3-delta (CGO-SCF-SFC), was developed through automatic phase-separation of ceramic precursors. The membrane showed improved H-2 separation performance and enhanced CO2-tolerance, achieving a stable hydrogen separation flux of 0.33 mL min(-1) cm(-2) under CO2-containing atmospheres.
SEPARATION AND PURIFICATION TECHNOLOGY
(2021)
Article
Engineering, Environmental
Guobin Qin, Jinxiao Bao, Jianquan Gao, Fei Ruan, Shengli An, Zhenbo Wang, Li Li
Summary: BaZrO3-based proton conductors show enhanced grain boundary conductivity and sintering performance through co-doping of Sc and Gd at B site. The incorporation of Sc promotes the generation of proton defects and lowers the proton migration energy barrier. Clustering of positively charged oxygen vacancy to acceptors suppresses proton trapping, improving long-range proton transport and bulk conductivity. Co-doping of Gd and Sc significantly reduces the Schottky barrier height and space charge layer width, resulting in higher grain boundary conductivity.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Thermodynamics
Katarina Muzina, Stanislav Kurajica, Filip Brlekovic, Drazan Jozic, Goran Drazic, Lucija Volf, Helena Bach-Rojecky
Summary: In this study, the grain growth kinetics of copper-doped ceria nanoparticles were investigated. It was found that doping with copper improves the thermal stability of ceria, and the sample with 40 mol.% of added copper has the slowest grain growth below 650 degrees C.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2023)
Article
Materials Science, Multidisciplinary
Apurv Dash, Koji Morita, Luca Balice, Robert Muecke, Olivier Guillon
Summary: This article demonstrates the enhanced plasticity of gadolinium-doped ceria (GDC) ceramics under mild and strong AC electric current, in terms of steady state creep rate under both compressive and tensile loading. A current density of 25 and 200 mA mm(-2) is used for the creep deformation, and the creep rate increases by up to two orders of magnitude under electric current. The stress exponent remains unchanged for creep experiments at 1200 °C with and without electric current, suggesting a grain boundary sliding (GBS) mechanism of plastic deformation in both cases. The field-enhanced creep rate is attributed to the interaction of space-charge layer and the electric field resulting in enhanced GBS. A higher current density results in enhanced ductility of GDC even when the Joule heating effect is compensated by reducing the furnace temperature.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Bharathi Bandi, Abhijit Chatterjee
Summary: The ionic conductivity of polycrystalline aliovalently-doped solid oxide electrolytes is lower than that of single-crystal material due to slow ionic movement at the grain boundary. Traditional models fail to consider the chemical interactions and atomic structure at the grain boundary. Molecular dynamics simulations reveal chemical oscillation in the space-charge region, resulting from competing chemical, electrostatic, and elastic interactions. The characteristics of the space charge layer differ in each grain boundary, and an alternative theory explaining these chemical oscillations is proposed.
Article
Materials Science, Multidisciplinary
Akihiro Ishii, Hibiki Ishijima, Kosei Kobayashi, Itaru Oikawa, Hitoshi Takamura
Summary: The key element for low-temperature sintering of Sm-doped CeO2 was found to be aluminum, which was spontaneously introduced through a chemical reaction with mixed lithium and alumina crucible. Zirconium was also introduced through ball-mill processing. Both aluminum and zirconium play an important role in reducing the melting point and achieving low-temperature sintering.
Article
Chemistry, Multidisciplinary
Ran Gao, Abhinav C. P. Jain, Shishir Pandya, Yongqi Dong, Yakun Yuan, Hua Zhou, Liv R. Dedon, Vincent Thoreton, Sahar Saremi, Ruijuan Xu, Aileen Luo, Ting Chen, Venkatraman Gopalan, Elif Ertekin, John Kilner, Tatsumi Ishihara, Nicola H. Perry, Dallas R. Trinkle, Lane W. Martin
ADVANCED MATERIALS
(2020)
Article
Chemistry, Multidisciplinary
Ming Li, Hongjun Niu, John Druce, Helena Tellez, Tatsumi Ishihara, John A. Kilner, Hripsime Gasparyan, Michael J. Pitcher, Wen Xu, J. Felix Shin, Luke M. Daniels, Leanne A. H. Jones, Vin R. Dhanak, Dingyue Hu, Marco Zanella, John B. Claridge, Matthew J. Rosseinsky
ADVANCED MATERIALS
(2020)
Article
Nanoscience & Nanotechnology
Ozden Celikbilek, Andrea Cavallaro, Gwilherm Kerherve, Sarah Fearn, Odette Chaix-Pluchery, Ainara Aguadero, John A. Kilner, Stephen J. Skinner
ACS APPLIED MATERIALS & INTERFACES
(2020)
Article
Chemistry, Physical
Kulbir K. Ghuman, Elisa Gilardi, Daniele Pergolesi, John Kilner, Thomas Lippert
JOURNAL OF PHYSICAL CHEMISTRY C
(2020)
Article
Instruments & Instrumentation
M. Niania, M. Sharpe, R. Webb, J. A. Kilner
NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS
(2020)
Article
Multidisciplinary Sciences
Navaratnarajah Kuganathan, Michael J. D. Rushton, Robin W. Grimes, John A. Kilner, Evangelos I. Gkanas, Alexander Chroneos
Summary: Atomistic simulation methods show that the most favourable disorder process in tetragonal garnet-type Li7La3Zr2O12 involves loss of Li2O, resulting in lithium and oxygen vacancies that promote vacancy mediated self-diffusion. The activation energy for lithium migration is much lower than that for oxygen, indicating that oxygen diffusion in this material can be facilitated at higher temperatures.
SCIENTIFIC REPORTS
(2021)
Article
Chemistry, Multidisciplinary
Ran Gao, Abel Fernandez, Tanmoy Chakraborty, Aileen Luo, David Pesquera, Sujit Das, Gabriel Velarde, Vincent Thoreton, John Kilner, Tatsumi Ishihara, Slavomir Nemsak, Ethan J. Crumlin, Elif Ertekin, Lane W. Martin
Summary: The efficiency of solid-oxide fuel cells and electrolyzers is determined by solid-gas interactions at electrode surfaces. The study on La0.8Sr0.2Co0.2Fe0.8O3 reveals a strong correlation between surface-gas kinetics and crystal orientation of perovskite electrodes, with (111)-oriented surfaces showing higher activity. Electrochemical impedance spectroscopy and electrical conductivity relaxation measurements indicate a surface-orientation dependency of gas-exchange kinetics, with all surfaces having the same reaction mechanisms and rate-limiting steps.
ADVANCED MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Yao Zhao, John Kilner, Tatsumi Ishihara, Kazunari Yoshizawa, Aleksandar Staykov
Summary: In this study, the impact of the partial covalent character of cations on their ionic diffusivity in La1-xSrxGayMg1-yO3-delta perovskite was computationally determined using density functional theory. The results revealed that cations with stronger covalent character had lower diffusivity compared to cations with more ionic character. The migration pathway of B-site cations was found to be curved to maximize electronic interactions with surrounding oxide ions.
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
(2022)
Article
Electrochemistry
V Thoreton, M. Niania, J. Druce, H. Tellez, J. A. Kilner
Summary: Measurements of oxygen diffusivity in ceramic samples of the mixed ionic electronic conductor La0.6Sr0.4Co0.2Fe0.8O3_(delta) (LSCF6428) revealed the presence of grain boundary tails in diffusion profiles at temperatures below 600 degrees C. Analysis of these tails provided values for the grain boundary diffusion products (D-gb delta). The activation enthalpies for both grain boundary and lattice diffusion were similar, indicating a common diffusion mechanism. Comparison with literature values showed that the D-gb delta values obtained for LSCF6428 were the highest recorded for any oxide material. The reasons for this high value, including nonstoichiometry of the lattice and the presence of twin boundaries, were discussed.
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2022)
Article
Chemistry, Physical
Zijie Sha, Gwilherm Kerherve, Matthijs A. van Spronsen, George E. Wilson, John A. Kilner, Georg Held, Stephen J. Skinner
Summary: A study investigated the surface reactions and composition of a mixed ionic and electronic conducting perovskite oxide. The results showed that the surface lattice oxygen is the significant redox active species, rather than the transition metal cations. The study also observed higher concentrations of surface oxygen vacancies and the formation of hydroxyl groups in water vapor. Furthermore, the study found that the concentration of Sr surface species increased over time in dry oxygen, while less Sr contents were observed in water vapor. The findings provide crucial understanding for the design and performance of electrocatalytic electrodes.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Matthaeus Siebenhofer, Andreas Nenning, George E. Wilson, John A. Kilner, Christoph Rameshan, Markus Kubicek, Juergen Fleig, Peter Blaha
Summary: This study investigates the effects of sulphur adsorbates and other SOFC poisons on the electronic and ionic properties of an SrO-terminated LSC surface and its oxygen exchange kinetics. Experimental and computational methods were used to analyze the surface modifications caused by the adsorbates. The results show that sulphur adsorbates strongly deactivate the LSC surface and affect oxygen vacancy formation energies. The study also reveals a correlation between work function changes and redistributed charge with the acidity of the adsorbed oxide.
JOURNAL OF MATERIALS CHEMISTRY A
(2023)
Article
Chemistry, Physical
Zijie Sha, Zonghao Shen, Eleonora Cali, John A. A. Kilner, Stephen J. J. Skinner
Summary: The effect of operating conditions on the surface composition and evolution of a perovskite oxide, (La0.8Sr0.2)(0.95)Cr0.5Fe0.5O3-delta (LSCrF8255), was investigated. Different environments were used to analyze the perovskite materials' applications as electrodes in electrochemical energy conversion devices. A variety of surface characterization techniques were employed, and the results showed that the operating conditions had a significant impact on surface segregation and phase separation.
JOURNAL OF MATERIALS CHEMISTRY A
(2023)
Article
Energy & Fuels
Rowena H. Brugge, Richard J. Chater, John A. Kilner, Ainara Aguadero
Summary: The current lithium ion battery technology poses safety risks, with the development of solid ceramic electrolytes offering a safer alternative for the next generation of all-solid-state batteries. However, the lithium diffusion behavior in these solid electrolytes and transport properties at the metal anode interface are not well understood. The proposed methodology aims to obtain lithium diffusion coefficients of bulk solid ceramic electrolytes and study their interfaces with electrodes for further optimization and performance enhancement in solid-state lithium batteries and hybrid systems.
JOURNAL OF PHYSICS-ENERGY
(2021)
Article
Chemistry, Physical
Vincent Thoreton, Mathew Niania, John Kilner
Summary: The study investigates the oxygen transport kinetics under humidified oxygen conditions through isotopic exchange depth profiling. It reveals that the surface exchange coefficient of water is higher than that of molecular oxygen, suggesting that water tends to occupy the active exchange sites at the material surface and exchange oxygen more rapidly than molecular oxygen.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Mathew A. R. Niania, Andrew K. Rossall, Jaap A. Van den Berg, John A. Kilner
JOURNAL OF MATERIALS CHEMISTRY A
(2020)