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Your search keyword '"Janek, Juergen"' showing total 120 results
Start Over Author "Janek, Juergen" Publication Type Academic Journals
120 results on '"Janek, Juergen"'

19. YSZ thin films with minimized grain boundary resistivity

Author

Mills, Edmund M, Kleine-Boymann, Matthias, Janek, Juergen, Yang, Hao, Browning, Nigel D, Takamura, Yayoi, and Kim, Sangtae

Subjects
Chemical Sciences, Physical Chemistry, Engineering, Physical Sciences, Materials Engineering, Chemical Physics, Chemical sciences, Physical sciences
Abstract

In recent years, interface engineering of solid electrolytes has been explored to increase their ionic conductivity and improve the performance of solid oxide fuel cells and other electrochemical power sources. It has been observed that the ionic conductivity of epitaxially grown thin films of some electrolytes is dramatically enhanced, which is often attributed to effects (e.g. strain-induced mobility changes) at the heterophase boundary with the substrate. Still largely unexplored is the possibility of manipulation of grain boundary resistivity in polycrystalline solid electrolyte films, clearly a limiting factor in their ionic conductivity. Here we report that the ionic conductivity of yttria stabilized zirconia thin films with nano-columnar grains grown on a MgO substrate nearly reaches that of the corresponding single crystal when the thickness of the films becomes less than roughly 8 nm (smaller by a factor of three at 500 °C). Using impedance spectroscopy, the grain boundary resistivity was probed as a function of film thickness. The resistivity of the grain boundaries near the film-substrate interface and film surface (within 4 nm of each) was almost entirely eliminated. This minimization of grain boundary resistivity is attributed to Mg(2+) diffusion from the MgO substrate into the YSZ grain boundaries, which is supported by time of flight secondary ion mass spectroscopy measurements. We suggest grain boundary "design" as an attractive method to obtain highly conductive solid electrolyte thin films.

Published
2016

29. Mechanism of ORR and OER in non-aqueous electrolytes: general discussion.

Author

Attard, Gary A., Bruce, Peter G., Calvo, Ernesto J., Chen, Yuhui, Curtiss, Larry A., Dewar, Daniel, Ellison, James H. J., Fernández-Vidal, Julia, Freunberger, Stefan A., Gao, Xiangwen, Grey, Clare P., Hardwick, Laurence J., Horwitz, Gabriela, Janek, Juergen, Johnson, Lee R., Jónsson, Erlendur, Karunarathne, Shadeepa, Matsuda, Shoichi, Menkin, Svetlana, and Mondal, Soumyadip

Abstract

This document is a collection of discussions among researchers about various aspects of oxygen reactions in non-aqueous electrolytes, specifically in the context of lithium-oxygen batteries. The researchers discuss topics such as the purity of electrolyte solutions, the choice of electrode material, the role of different cations, and the effects of impurities on experimental results. They also explore the mechanisms and properties of singlet oxygen and its impact on battery degradation. The researchers provide insights and explanations based on their experiments and calculations, while acknowledging the need for further investigation in some areas. Overall, more research is needed to fully understand the complexities of these reactions and their implications for battery performance. [Extracted from the article]

Published
2024
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30. Materials for stable metal–oxygen battery cathodes: general discussion.

Author

Attard, Gary A., Calvo, Ernesto J., Curtiss, Larry A., Dewar, Daniel, Ellison, James H. J., Gao, Xiangwen, Grey, Clare P., Hardwick, Laurence J., Horwitz, Gabriela, Janek, Juergen, Johnson, Lee R., Jordan, Jack W., Matsuda, Shoichi, Mondal, Soumyadip, Neale, Alex R., Ortiz-Vitoriano, Nagore, Temprano, Israel, Vailaya, Ganesh, Wachsman, Eric D., and Wang, Hsien-Hau

Abstract

This document is a discussion from the journal Faraday Discussions about materials for stable metal-oxygen battery cathodes. The discussion covers various topics such as the role of oxygen crossover in creating the solid electrolyte interface, the redox reactions of the iodide/triiodide couple, the effect of electrolyte composition on redox processes, the source of side reactions in the battery, the role of ionic liquids in changing product morphology, and the importance of water content in electrode reactions. The authors also discuss the stability of sodium salts in solvents and the stability of the battery with the addition of an ionic liquid. The document concludes with a discussion on the deposition of lithium superoxide and its dissolution into the electrolyte solution. The text discusses the experimental observations and calculations related to the growth and stabilization of LiO2 discharge products in lithium-oxygen batteries. The authors note that the epitaxial interfacial energy provides sufficient stabilization energy for LiO2 growth. The text also mentions the solubility of LiO2 in electrolytes and addresses questions about strain, template stabilization, and the conductivity of LiIr3 alloy. Experimental evidence for LiO2 and its disproportionation is mentioned, as well as the potential for using single crystal approaches to test these ideas. The text discusses various aspects of lithium-oxygen (Li-O2) and potassium-oxygen (K-O2) battery systems. It mentions the use of Ir nanoparticles to stabilize LiO2 as a discharge product and the lattice [Extracted from the article]

Published
2024
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