Advanced Materials for Energy Conversion and Storage VII: Functional Materials for Energy I
Sponsored by: TMS Functional Materials Division, TMS: Energy Conversion and Storage Committee
Program Organizers: Jung Choi, Pacific Northwest National Laboratory; Soumendra Basu, Boston University; Amit Pandey, Lockheed Martin Space; Paul Ohodnicki, University Of Pittsburgh; Kyle Brinkman, Clemson University; Partha Mukherjee, Purdue University; Surojit Gupta, University of North Dakota
Tuesday 2:00 PM
March 16, 2021
Room: RM 23
Location: TMS2021 Virtual
Session Chair: Jung Pyung Choi, Pacific Northwest National Laboratory; Peter Godart, Massachusetts Institute of Technology
2:00 PM
Assessment of Grain Boundary Composition on the Thermodynamics Structural Properties in Concentrated Ceramic Oxides: Tara Boland1; Arunima Singh1; Peter Rez1; Peter Crozier1; 1Arizona State University
Ceramic oxides are used for a wide variety of technologically relevant applications from electrochemical devices, novel resistive switching devices, and oxygen sensors. Applications such as these typically rely upon the ability of oxides to conduct ions efficiently through the lattice. Recent nanoscale compositional characterization of the GB composition has shown different nominal concentrations of solutes could result in orders of magnitude increase in GB ionic conductivity relative to the undoped samples. This study assesses the properties of alkaline-earth metal dopants that, when present in high concentrations, significantly impact the GB properties in concentrated solid solutions often dominating the material's response. Computational modeling is employed using density functional theory to optimize the GB interfacial structure for various GB misorientations in CeO2. This study further develops our understanding of high solute GB composition enabling the development of methods such as selective doping to improve macroscopic ionic conductivity for GBs.
2:20 PM
A Novel and Practical Water-reactive Aluminum Fuel from Scrap: Peter Godart1; Douglas Hart1; 1MIT
Presented here is a novel aluminum fuel that can be derived directly from scrap feed stock. Typically, bulk aluminum has an oxide layer that prevents it from reacting with water at practical temperatures; however, our research has shown that by shredding and compacting a wide variety of aluminum stock and applying a minimal surface treatment of gallium and indium can disrupt the oxide layer at the grain boundaries, allowing the exothermic reaction to proceed to >99% completion, producing clean hydrogen gas and valuable boehmite in the process. Our experiments also show the robustness of this process to the presence of paint and other contaminants. Given that global recycling rates have been reduced recently by numerous factors, including complications with sorting waste by alloy content and lack of economic incentive, this approach provides another avenue for managing this waste stream, generating considerable value in the process.
2:50 PM
Aging Behavior of Advanced Martensitic Steels for Next Generation Diesel Engine Pistons: Dean Pierce1; Govindarajan Muralidharan1; Larry Allard1; Jon Poplawsky1; Ercan Cakmak1; Artem Trofimov1; Hsin Wang1; Allen Haynes1; 1Oak Ridge National Laboratory
Combustion temperatures and pressures in heavy duty diesel engines are continually increasing to meet next generation environmental and efficiency requirements. However, these new temperature and pressure regimes for diesel engines are imposing severe and unique demands on current piston materials. Material degradation mechanisms, such as high cycle mechanical fatigue, thermal fatigue, microstructural aging, and oxidation interact severely and are accelerated. The focus of the present work is to understand the effect of temperature, time, and composition on the microstructural evolution, aging behavior, mechanical properties, and oxidation characteristics of candidate martensitic steels for next generation piston applications at temperature from 500 to 650 °C. High resolution scanning transmission electron microscopy, atom probe tomography, x-ray diffraction, and SEM are utilized to characterize carbide size and coarsening kinetics, and oxidation behavior. The quantitative results of these studies are then used to evaluate the contribution of different mechanisms to the elevated temperature strength.
3:10 PM
Breaking Atomic-level Ordering via Biaxial Strain in Functional Oxides: A DFT Study: Kanishk Rawat1; Dilpuneet Aidhy1; Dillon Fong2; 1University of Wyoming; 2Argonne National Laboratory
We elucidate the effects of interfacial strain on oxygen vacancy ordering in fluorite δ-Bi2O3 and perovskite LaNiO2.5, and cation ordering in pyrochlore Gd2Ti2O7 using first principles calculations. By applying biaxial strains, we find that the <110>-<111> oxygen vacancy order in δ-Bi2O3 is broken resulting in faster diffusion of oxygen ions. Similarly, the interfacial strain can be used to leverage both ordered and disordered arrangement of vacancies in LaNiO2.5. Finally, the interfacial strain can also break the cation order in Gd2Ti2O7, where Gd and Ti antisites can be created on the cation sublattice that contributes to enhanced radiation tolerance and oxygen diffusivity. These results show that interfacial strain, which is commonly observed at heterointerfaces, can be used to gain control over ordered and disordered arrangement of defects that may open new opportunities to functionalize ceramic oxides.
3:30 PM
Direct Correlation of Anion Conductivity with Grain Boundary Defect Chemistry in Concentrated Oxide Solid Solutions: Hasti Vahidi1; Shengquan Xuan1; William Bowman1; 1University of California, Irvine
Ionic conductivity of polycrystalline oxides is impacted by grain boundaries (GBs), which can exhibit substantially lower conductivity than grains. This is due to space charge layers (SCLs) at the GBs, where mobile charge carrier, i.e. oxygen vacancies, depletion has been observed. Modeling of the SCLs has been mainly focused on dilute solutions, using dilute-solution thermodynamic approximations, with only few studies on concentrated solid solutions where point defect concentrations exceed ~ 1 at%. This work aims to bridge the gap between GB ionic conductivity and defect chemistry in heavily Gd-substituted CeO2 (GdxCe1-xO2) using direct measurements of chemical and functional properties over a range of compositions. Electrochemical impedance spectroscopy (EIS) is used to measure grain and GB conductivity, and TEM-based electron energy-loss spectroscopy (EELS) is used to quantify the local defect chemistry. Together, these data contribute to development of models of GBs and interface transport ion mechanisms in concentrated solid solutions.
3:50 PM
Effect of Alloying Elements (Ni, Co) on Low Pt-transition Metals Nanowires for Oxygen Reduction Electrocatalysts: Jaeyoung Yoo1; Youngtae Park1; Changsoo Lee2; Hyuck Mo Lee1; 1KAIST; 2KIER
Proton exchange membrane fuel cells (PEMFCs) are one of the most attractive sustainable energy conversion technologies, because they directly convert fuel into electricity efficiently without generating any pollutants. However, commercialization of PEMFCs is limited by the slow rate of the oxygen reduction reaction at cathodes. Large amounts of platinum catalyst are required and the high cost of platinum is problematic. To attain a competitive price, we synthesized nanowire catalysts composed of high mass activity platinum-transition metals (Ni, Co) with a facile method. It maintained the high activity even though the content of transition metals becomes higher than Pt. It showed the enhanced mass activity compared with Pt nanowire and Pt/C. The density functional theory revealed that the enhanced activity resulted from the change of reaction mechanism.
4:10 PM
Electrochemical Behavior of Palladium in 1-Ethyl-3-Methylimidazolium Chloride Ionic Liquid: Zhang Wu1; Batric Pesic2; 1Shenyang Ligong University; 2University of Idaho
Palladium is an important platinum group metal because of, among many other, its exceptional catalytic properties. As electrodeposition from aqueous solutions causes hydrogen adsorption and embrittlement the evaluation of using aprotic electrolytes, such as ionic liquids, is underway. By using rotating disk technique (glassy carbon as working electrode), we provide a systematic study on the electrochemical behavior of palladium in 1-ethyl-3-methylimidazolium chloride ionic liquid by using standard electrochemical techniques, such as cyclic voltammetry, current-time transients, and square wave voltammetry. It was found that palladium electrochemistry is characterized by two cathodic and two anodic waves, all dependent on the potential range in which they are produced. It was discovered that two cathodic waves are the results of two different surface states rather than two difference palladium species as claimed in the literature. The reversibility of electrochemical reactions and the reaction rate results will be presented and discussed.