Tuesday, November 17, 2020
Materials Engineering and Sciences Division (08) (PreRecorded+)
Christopher J. Bartel1, Akira Miura2, Yusuke Goto3, Yoshikazu Mizuguchi3, Chikako Moriyoshi4, Yoshihiro Kuroiwa4, Yongming Wang5, Toshie Yaguchi6, Manabu Shirai6, Masanori Nagao7, Nataly Carolina Rosero-Navarro2, Kiyoharu Tadanaga2, Gerbrand Ceder1,8 and Wenhao Sun9, (1)Materials Science and Engineering, University of California, Berkeley, Berkeley, CA, (2)Faculty of Engineering, Hokkaido University, Sapporo, Japan, (3)Department of Physics, Tokyo Metropolitan University, Hachioji, Japan, (4)Department of Physical Science, Hiroshima University, Higashihiroshima, Japan, (5)Creative Research Institution, Hokkaido University, Sapporo, Japan, (6)Hitachi High Technologies, Hitchinaka, Japan, (7)Center for Crystal Science and Technology, University of Yamanashi, Kofu, Japan, (8)Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, (9)Materials Science and Engineering, University of Michigan, Ann Arbor, MI
Solid-state synthesis is the bedrock of inorganic materials chemistry and an integral component of materials design. However, this approach is typically a “black box”, where the only observation is what formed from the precursor materials after reaction at a predetermined set of conditions. The opaque nature of this process precludes an understanding of how the final phases formed from the precursors (e.g., through the formation of intermediate phases). In order to rationally synthesize new inorganic materials, it is critical to not only understand but predict what intermediates form and how they influence the reaction towards the synthesized phase(s).
In this work, we study the synthesis of the classic high-temperature superconductor, YBa2Cu3O7-x (YBCO). This material has been synthesized many thousands of times, including in countless undergraduate laboratories for the demonstration of superconductivity upon cooling with liquid nitrogen. Despite the prominence of this synthesis, little is actually known about how or why the chosen precursors form YBCO. Using in situ synchrotron X-ray diffraction (XRD) and transmission electron microscopy (TEM), we are able to show the evolution of phases during YBCO synthesis for the first time. Importantly, at each step of the synthesis pathway, we rationalize the phase evolution within a thermodynamic framework built upon density functional theory (DFT) calculations and a machine-learned descriptor for compound thermochemistry. Ultimately, we present a general framework for understanding pathways in solid-state synthesis reactions that can be utilized for the future rational synthesis of new compounds.
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