Atomistic studies of grain boundary evolution during cold sintering of proton conducting oxides

• Applicants: Professor Dr.-Ing. Olivier Guillon; Professor Dr. Joachim Mayer
• Subject Area: Glass, Ceramics and Derived Composites ; Synthesis and Properties of Functional Materials
• Term: from 2021 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 455434186

• Final Report Year: 2024

Final Report Abstract

In order to achieve the climate protection targets, a far-reaching decarbonization of society and industry is necessary. High-temperature fuel and electrolysis cells based on proton-conducting ceramics can play an important role in this process. In the DFG project ‘Atomistic investigations into grain boundary development during cold sintering of proton-conducting oxides’, novel processing methods for hard-to-process ceramic materials based on BaZrO3 were therefore investigated in detail. To this end, cold sintering was used as a new type of sintering process that enables processing at greatly reduced temperatures, which both increases energy efficiency and materials integration and enables new functionalities. Chemical processes at grain boundaries play an important role both during the sintering process and for the properties of the ceramics produced. The results of the research project clearly show that different chemical factors of the starting materials can be used to influence the processing based on cold sintering. The composition of the starting powders has a particularly large influence here. Thanks to the innovative approach, temperatures for sintering can be lowered and excellent grain boundary properties can be maintained at the same time. High-resolution electron microscopy was used to characterize the composition and structure of these grain boundaries. The results obtained form the basis for further studies that aim to transfer the cold sintering process to layer systems in order to produce full electrochemical cells.

Publications

• Enhanced metal exsolution at the non-polar (001) surfaces of multi-faceted epitaxial thin films. Journal of Physics: Energy, 5(1), 014002.
  Weber, Moritz L.; Kindelmann, Moritz; Wessel, Egbert; Sarantopoulos, Alexandros; Menzler, Norbert H.; Dittmann, Regina; Waser, Rainer; Guillon, Olivier; Lenser, Christian & Gunkel, Felix
  
• Processing map to control the erosion of Y 2 O 3 in fluorine based etching plasmas. Journal of the American Ceramic Society, 105(5), 3498-3509.
  Kindelmann, Moritz; Weber, Moritz L.(ukas); Stamminger, Mark; Buschhaus, Rahel; Breuer, Uwe; Bram, Martin & Guillon, Olivier
  
• Cold sintering of BaZr0.7Ce0.2Y0.1O3-δ ceramics by controlling the phase composition of the starting powders. Scripta Materialia, 224, 115147.
  Kindelmann, Moritz; Ebert, Julian Norbert; Scheld, Walter Sebastian; Deibert, Wendelin; Meulenberg, Wilhelm Albert; Rheinheimer, Wolfgang; Bram, Martin; Mayer, Joachim & Guillon, Olivier
  
• Reactive FAST/SPS sintering of strontium titanate as a tool for grain boundary engineering. Journal of the European Ceramic Society, 43(15), 6925-6933.
  Zahler, M. Pascal; Jennings, Dylan; Kindelmann, Moritz; Guillon, Olivier & Rheinheimer, Wolfgang
  
• Cold sintering of BaZr0.8Y0.2O3-ẟ ceramics: Phase formation and grain boundary properties. Journal of the European Ceramic Society, 44(5), 2744-2753.
  Kindelmann, Moritz; Ebert, Julian N.; Jennings, Dylan; Sebold, Doris; Rheinheimer, Wolfgang; Bram, Martin; Mayer, Joachim & Guillon, Olivier
  
• Cold sintering of proton-conducting half cells based on BaZr0.7Ce0.2Y0.1O3-δ/NiO. Ceramics International, 50(19), 37373-37378.
  Kindelmann, Moritz; Bram, Martin; Mayer, Joachim & Guillon, Olivier
  
• Controlling grain boundary segregation to tune the conductivity of ceramic proton conductors. American Chemical Society (ACS).
  Kindelmann, Moritz; Povsturgar, Ivan; Kuffer, Severin; Jennings, Dylan; Ebert, Julian N.; Weber, Moritz L.; Zahler, M. Pascal; Escolantico, Sonia; Almar, Laura; Serra, Jose M.; Kaghazchi, Payam; Bram, Martin; Rheinheimer, Wolfgang; Mayer, Joachim & Guillon, Olivier
  
• Correlative characterization of plasma etching resistance of various aluminum garnets. Journal of the American Ceramic Society, 107(11), 7105-7118.
  Stern, Christian; Schwab, Christian; Kindelmann, Moritz; Stamminger, Mark; Weirich, Thomas E.; Park, Inhee; Hausen, Florian; Finsterbusch, Martin; Bram, Martin & Guillon, Olivier
  
• Direct Atomic-Scale Investigation of the Coarsening Mechanisms of Exsolved Catalytic Nanoparticles. American Chemical Society (ACS).
  Jennings, Dylan; Weber, Moritz L.; Meise, Ansgar; Binninger, Tobias; Price, Conor; Kindelmann, Moritz; Reimanis, Ivar; Matsumoto, Hiroaki; Cao, Pengfei; Dittman, Regina; Kowalski, Piotr; Heggen, Marc; Guillon, Olivier; Mayer, Joachim; Gunkel, Felix & Rheinheimer, Wolfgang
  
• Flash‐induced defects in single‐crystal 8YSZ characterized by TEM, XRD, and Raman spectroscopy. Journal of the American Ceramic Society, 107(9), 5786-5800.
  Jo, Seohyeon; Kindelmann, Moritz; Jennings, Dylan; Balice, Luca; Sohn, Yoo Jung; Scheld, Walter Sebastian; Bram, Martin; Guillon, Olivier; Mayer, Joachim & Raj, Rishi
  
• Grain boundary segregation in iron doped strontium titanate: From dilute to concentrated solid solutions. Acta Materialia, 273, 119941.
  Jennings, Dylan; Zahler, M. Pascal; Wang, Di; Ma, Qianli; Deibert, Wendelin; Kindelmann, Moritz; Kübel, Christian; Baumann, Stefan; Guillon, Olivier; Mayer, Joachim & Rheinheimer, Wolfgang
  
• Highly conductive grain boundaries in cold-sintered barium zirconate-based proton conductors. Journal of Materials Chemistry A, 12(7), 3977-3988.
  Kindelmann, Moritz; Escolastico, Sonia; Almar, Laura; Vayyala, Ashok; Jennings, Dylan; Deibert, Wendelin; Meulenberg, Wilhelm A.; Rheinheimer, Wolfgang; Bram, Martin; Serra, Jose M.; Mayer, Joachim & Guillon, Olivier