Grain Boundaries, Interfaces, and Surfaces: Fundamental Structure-Property-Performance Relationships: Interfaces in Functional Materials
Sponsored by: ACerS Basic Science Division
Program Organizers: Shen Dillon, University of California, Irvine; Wolfgang Rheinheimer, University of Stuttgart; Catherine Bishop, University of Canterbury; Ming Tang, Rice University; John Blendell, Purdue University; Wayne Kaplan, Technion - Israel Institute Of Technology; Melissa Santala, Oregon State University
Monday 8:00 AM
October 10, 2022
Room: 335
Location: David L. Lawrence Convention Center
Session Chair: Shen Dillon, University of California, Irvine; Wayne Kaplan, Technion - Israel Institute of Technology
8:00 AM
Understanding of Interface-property Relationships of Vertically Aligned Mixed Ionic Electronic Conductor-ionic Conductor Heterostructures: Gene Yang1; Mohammad El Loubani1; Dongkyu Lee1; 1University of South Carolina
To develop oxide-based energy applications such as solid oxide fuel cells, the sluggish reaction kinetics at the electrode needs to be overcome. Among various approaches to improve the electrode performance, oxide multilayer thin films consisting of mixed ionic-electronic conducting oxides (MIEC) and ionic conductors have recently attracted increasing attention since both ion conduction and electrocatalytic activity can be enhanced by interfacial strain. However, nanoscale thickness required for maintaining interfacial strain along the lateral direction is impractical. Thus, new design concepts are required to realize heterostructures with micron-scale thickness for commercial applications. In this work, a combination of MIECs and Gd-doped CeO2 (GDC) is used in the form of vertically aligned heterostructures to investigate the relationships between structure, interface, and material property. Our finding will provide a rational design strategy to precisely control the strained interfaces facilitating the development of high-performance electrochemical energy applications.
8:20 AM
Influence of Misfit Dislocations on Oxygen Vacancy Migration at SrTiO3/BaZrO3 Heterointerfaces: Will Ebmeyer1; Pratik Dholabhai1; 1Rochester Institute of Technology
Mismatched complex oxide heterostructures and thin films have remarkable promise for next-generation electrolytes in solid oxide fuel cells (SOFCs), wherein misfit dislocations impact interfacial ionic transport. Nevertheless, fundamental understanding of atomic scale structure of misfit dislocations and their influence on oxygen vacancy migration at functional interfaces is lacking. For SrTiO3/BaZrO3 heterostructure, we employed atomistic simulations to predict the thermodynamic stability and atomic scale structure of misfit dislocations, which is found to depend on interface layer chemistry. Using high-throughput simulations, hundreds of activation energy barriers were determined for oxygen vacancy migration at different interfaces. Higher activation energies are observed in the vicinity of dopants, whereas migration paths near misfit dislocation lines are lower in energy, but vary somewhat depending on interface chemistry. Results on oxygen ion migration at oxide heterointerfaces offer new opportunities to unravel the untapped potential of thin film SOFC electrolytes. We acknowledge support from NSF CAREER Award DMR-2042311.
8:40 AM Invited
Electronic Structure Engineering through Atomic-scale Strain Control In Complex Oxide Heterostructures: Peter A. van Aken1; 1Max Planck Institute for Solid State Research
In complex oxide systems, the coupling of atomic configurations and electronic degrees of freedom plays a fundamental role in understanding exotic phenomena. Modifying strain by depositing epitaxial thin films on substrates with different lattice spacing results in precise control of the local physical behavior enabling disentangling competing interactions and tuning novel ground states. Here, I demonstrate how strain locally alters physical properties in two different complex oxide systems using analytical HR-STEM. I first describe the electron redistribution and confinement or delocalization depending on the epitaxial strain in LiV2O4 films grown on SrTiO3 and MgO substrates, revealing two competing behaviors, a metallic charge-disordered phase on SrTiO3 and an insulating charge-ordered phase on MgO. The second part focuses on La0.5Sr0.5MnO3-La2CuO4 heterostructures grown on three different substrates, where epitaxial-strain-induced charge rearrangement gives rise to different magnetic phases, an interfacial antiferromagnetic layer and a ferromagnetic metallic region away from the interfaces.
9:10 AM Invited
Grain Boundary Metal-insulator Transitions in Ionic Ceramics: Edwin Garcia1; 1Purdue University
Surfaces and interfaces in ionic ceramics play a pivotal role in defining the transport limitations in many of existing and emerging applications in energy-related systems, including fuel cells, rechargeable batteries, as well as electronics such as those found in semiconducting, mixed ionic, ferroelectric, and piezotronic applications. By starting from a thermodynamically consistent phase field formulation, an update on the progress on the analytical and numerical modeling effort will be presented, describing the structural, electrical, mechanical, and thermochemical conditions that will induce an interfacial electrically conductive to insulator transition, their stability and phase transformation kinetics. Applications to lithium-ion battery systems, including LiNiMnCoO2, LiCoO2, and LiFePO4 will be discussed, highlighting the different mechanisms controlling their interfacial behavior. The impact on the macroscopically observed frequency-dependent impedance behavior will be detailed. Comparisons against available experimental data will be made.
9:30 AM
Impact of Grain Boundaries on the Dielectric Behavior of Graphite: Deborah Chung1; Xiang Xi1; 1State University of New York Buffalo
It is well-known than grain boundaries and interfaces affect the electrical conduction behavior. However, their effects on the dielectric behavior have not been previously addressed, in spite of the negative effect of electric polarization on electrical conduction. The polarization (DC/AC) is due to the interaction of a small fraction of the charge carriers with the atoms. This work shows that a decrease in the grain size of polycrystalline graphite increases the resistivity slightly, but it increases the permittivity greatly. The carrier-atom interaction occurs mainly at the grain boundaries, which affect the polarization more than conduction. A decrease in the grain size also promotes the electret (permanent electric dipole) behavior, which is consistent with the asymmetry in the DC polarization upon polarity reversal. The graphite is important for electrochemical electrodes, sliding electrical contacts and heating elements, and represents the graphite allotrope family, which includes graphene, carbon fibers and carbon nanotubes.
9:50 AM Break
10:10 AM Invited
Grain Boundary Segregation and Impedance in Dielectric Ceramics: Elizabeth Dickey1; Andrew Aumen1; Seonghwan Hong1; 1Carnegie Mellon University
The grain boundary chemistry in dielectric materials can induce local variations in electrostatic potential, which can dominate the overall conductivity of polycrystalline materials. This talk will discuss grain boundary segregation phenomena in important electronic ceramics, focusing on the temperature-dependent contributions to the electronic conductivity. A combination of impedance spectroscopic analyses and transmission electron microscopy measurements of chemistry and local electrostatic potential and used to understand segregation phenomena in BaTiO3 co-doped for improved reliability. This work was supported by AFOSR grant number FA9550-19-1-0222.
10:40 AM
Moisture Incorporation and Degradation in Dielectrics and Piezoelectrics: John McGarrahan1; Elizabeth Dickey2; 1NC State University; 2Carnegie Mellon University
The time-dependent properties of dielectric and piezoelectric materials in humid environments are an important performance metric, as humidity-related degradation can dominate device lifetime in some applications. This research aims to understand the effects of proton incorporation in such environments by examining the diffusion kinetics of H+ in commercially relevant electroceramic systems. The work focuses on in-situ impedance measurements and tracer diffusion studies to examine incorporation pathways, mechanisms, and kinetics of H+ in BaTiO3. Specifically, the hydration kinetics for acceptor doped BaTiO3 will be shown as a function of temperature and acceptor concentration. Furthermore, an interpretation of a potential mechanism for the pH2O dependent conductivity in BaTiO3 will be examined. Our hypothesis regarding the hydration mechanism will be supported by secondary ion mass spectrometry (SIMS) studies on D2O hydrated polycrystalline BaTiO3. This work was funded by the Center for Dielectrics and Piezoelectric, an NSF Industry/University Cooperative Research Center, under grant IIP-1841466.
11:00 AM Invited
Advanced (S)TEM Characterization of the Role of Interfaces and Defects during Electrochemical Cycling of Oxide Based Solid Electrolytes and Electrode Materials: Kai Wang1; Ziming Ding1; Yushu Tang1; Georgian Melinte1; Xiaoke Mu1; Di Wang1; Ben Breitung1; Christian Kuebel1; 1Karlsruher Institute for Technolgie
Understanding the role of interfaces and defects on the electrochemical processes during battery cycling is critical for a targeted development of new battery materials. With this presentation, I will illustrate how the combination of analytical HR(S)TEM, 4D-STEM and tomography techniques (complemented by bulk X-ray spectroscopy) can be used to understand interface structures/networks and their evolution during electrochemical cycling. As one example for anodic processes, we have studied the conversion/alloying reaction of a high entropy oxide to understand the synergy between cations resulting in a stable conductive nanoscale network as essential contribution to the excellent electrochemical stability of the anode. As an example for the role of grain boundaries and interfaces in solid electrolytes, we have performed in-situ STEM studies to image sodium dendrite formation in sodium beta alumina directly relating microstructure and sodium segregation. The aim of this work is to connect the structural characterization and the electrochemical properties.
11:30 AM
Multiphysics-Based Data Analytics of LiMn2O4 Particles Decrepitation: Alfredo Sanjuan1; Edwin García1; 1Purdue University
Existing microstructural design approaches in rechargeable Lithium-Ion Batteries (LIBs) aimed to optimize length of life and reliability are based on empirical trial and error efforts or very specific to a particular preconceived notion of how an LIB is expected to fail. While LIB degradation can be result of multiple, often coupled mechanisms, the development of unbiased realistic fracture criteria is only possible by considering the data analytics of the space of possible chemomechanical decrepitation microstructural mechanisms.In this paper, by using an accelerated finite element implementation (with a wall time at least three orders of magnitude faster than conventional approaches), the different regimes of decrepitation in LiMn2O4 particles are identified and mapped out. Different charge-discharge processes are considered, and potential solutions to mitigate failure are discussed.