Controlled Synthesis, Processing, and Applications of Structural and Functional Nanomaterials: Ceramic Nanostructures and Energy Applications
Program Organizers: Haitao Zhang, University of North Carolina at Charlotte; Gurpreet Singh, Kansas State University; Kathy Lu, Virginia Tech; Edward Gorzkowski, Naval Research Laboratory ; Jian Shi, Rensselaer Polytechnic Institute; Kejie Zhao, Purdue University ; Michael Naguib, Tulane University
Wednesday 8:00 AM
October 2, 2019
Location: Oregon Convention Center
Session Chair: Edward Gorzkowski, Naval Research Laboratory; Jian Shi, Rensselaer Polytechnic Institute
8:00 AM Invited
Electroactive Materials for Divalent Ion Rechargeable Batteries: Guozhong Cao1; 1University of Washington
In this presentation, we will present our most recent research on the synthesis of various promising cathode materials for divalent ions including both magnesium and zinc, with controlled or tuned interlayer distance, bulk defects and surface chemistry to attain desired storage capacity and transport properties. The cathode materials investigated include vanadium oxides, vanadates, manganese oxides, and demonstrated excellent zinc-ion charge-discharge storage and rate performance. In addition, we will discuss the introduction of surface passivation layer on magnesium anode by the formation of an ionic conductive but electronic insulating layer.
Elaboration of Solid Nano-structured Electrolytes of Ce0.85-xGd0.15MxO2-ä (x = 0.03, 0.05 and M = Sm and La) and Measurement of Ionic Conductivity at Intermediate Temperatures: Karla María Rangel-Arreola1; Ena Athenea Aguilar-Reyes1; Carlos Alberto León-Patiño1; 1Universidad Michoacana de San Nicolas de Hidalgo
The production of electrolytes of ceria doped with aliovalent elements of the group of rare earths, such as Gd, La and Sm, presents an advantage with respect to the electrolytes of YSZ, since it has been shown that these systems are capable of having better conductivity at temperatures below 1000 °C. In the present work, ceramic powders of Ce0.85-xGd0.15MxO2-δ (x = 0, 0.03, 0.05 and M = Sm or La) were elaborated by means of chemical synthesis by co-precipitation, which allows to obtain nano-sized materials, 17.1 nm, and highly crystalline at room temperature. The electrolytes were then prepared using a uniaxial press and subjected to a conventional sintering cycle in air reaching densities of 81.90% and conductivity of 0.16 S·cm-1 at 900 °C. The goal for the future is the application of powders for the preparation of nanostructured electrolytes by means of the cathodic erosion technique.
An All Zirconia Ceramic Solid Oxide Fuel Cell with Improved Power Generation: John Drazin1; Dustin McLarty1; 1Washington State University
Solid oxide fuel cells (SOFC) have long held the promise for carbon free/carbon neutral power generation. After decades pursuing innovative system and stack geometries a consensus has emerged around atmospheric pressure, anode-supported planar SOFC with metallic interconnects, produced through tape casting, screen printing and thermal spray deposition. This design suffers from high operating temperatures, metal parts (high temperature stability), extremely precise geometric tolerancing, and inherent compromises in performance and durability necessary to address material incompatibilities. To combat these issues a redesign of the SOFC materials is needed. Therefore, in this work, we manufactured a new anode and cathode zirconia based ceramic and tested their resistivity from room temperature to 1000C. In addition, voltage-current curves were collected using hydrogen gas and air at atmospheric pressures between 400 to 1000C on a co-sintered button cell.
Thermal Conductivity Reduction in 7 wt% Yttria Doped Zirconia Nanocrystalline Ceramics: John Drazin1; James Wollmershauser2; Stephanie Wimmer2; Brian Donovan3; Edward Gorzkowski2; 1Washington State University; 2Naval Research Laboratory; 3United States Naval Academy
Thermal Barrier Coatings (TBCs) are an integral component of the thermal protection system in high temperature turbine engines made primarily out of 7 wt% yttria-doped zirconia (7YSZ). With future fuel efficiency requirements, the temperature of these engines will likely be increased requiring lower thermal conductivity in the TBCs to protect the metal substrate. Theoretical approaches predict that a nanocrystalline grain size can retard the thermal conductivity without hindering the mechanical properties. Therefore, in this work, we manufactures fully dense 7YSZ nanocrystalline ceramics, sub- 50 nm grains, and measured the thermal conductivity which was lowered by over 16% at room temperature. In addition, various sized polymer spheres were added to the YSZ compacts to be burned out producing pores in the final microstructure. The thermal conductivity was further reduced. This microstructure – property relationship was also successfully modeled using FEM code in both 2D and 3D.
Topochemical Conversion of Different Shaped BaTiO3 and Its Effect on Boosting Electrical Properties of Composite Materials: Jing Fu1; Haiyan Zhao1; Mupeng Zheng1; Mankang Zhu1; Yudong Hou1; 1Beijing University of Technology
The topochemical method (TCM) is one of the strategic approaches aimed at controlling ferroelectric oxide morphology. In this work, different shaped BaTiO3 filler, i.e. spherical particles , nanorods and platelets, have been synthesized by TCM through choosing the suitable precursor templates. The topochemical reaction process is accompanied by a localized solid-state compound transformation. Based on the principle of chemical thermodynamics, the topological mechanism related to the assembly of [TiO6] octahedron units has been proposed. Further, by selecting the filler of the specific morphology and optimizing the structural design of the polymer-based composite material, the flexible piezoelectric energy harvester and the energy-storage capacitor can be constructed. The enhancement mechanism of electrical performance has been discussed with respect to intrinsic polarization of filler, interfacial polarization and electric field distribution. This work has a good reference value for developing electrically functional composite material based on tailoring the shape and arrangement of ferroelectric filler.
9:50 AM Invited
Perovskite-based Functional Nanocomposites for Highly Stable and Efficient Hybrid Solar Cells: Yoon-Bong Hahn1; 1Chonbuk National University
Poor stability of perovskite solar cells (PSCs) has prevented the devices from practical applications that can withstand sustained long-term operation. Furthermore, most of presented PSCs utilize halogenated antisolvents such as toluene and chlorobenzene to assist perovskite crystal growth, but they are highly toxic and detrimental to environment. To solve such issues, we developed a simple method for the production of functional nanocomposites such as Ag-rGO, perovskite-NiO, perovskite/Ag-rGO, etc and utilized them for the fabrication of highly stable and efficient PSCs. In addition, to solve interfacial degradation whcih affects device performance Al2O3/NiO layers were inserted between elecrtron transport layer and active layer. By introducing the functional nanocomposites into PSCs with interface engineering, we obtained high efficiency of >18 % and excellent reproducibility. More importantly, the perovskite/Ag-rGO based PSCs without encapsulation showed significant enhancement in long-term stability over 330 days with retaining over 95 % of its photovoltaic parameters under ambient conditions.
10:20 AM Break
Scalable Electrospinning of CsH2PO4 Micro- and Nanometer Fibers for Solid Acid Fuel Cell Applications: Ryan McCarty1; Konstantinos Giapis2; Fernando Diaz Campos3; Mandy Abbott3; Calum Chisholm3; 1University of California, Irvine; 2California Institute of Technology; 3SAFCell
We designed and demonstrated a scalable approach to synthesize micro- and nanometer-sized fibers of Cesium dihydrogen phosphate (CsH2PO4) for solid acid fuel cell (SAFC) applications. Warm (250C) CsH2PO4 is utilized in SAFCs as an electrolyte membrane material for its high proton conductivity. In this application, high surface area electrodes are thought to increase fuel cell output; electrodes must also be porous to permit gas access. We employed a novel electrospinning device in a humidity-controlled environment to spin a “honey-like” viscus solution of water and CsPO3. After producing fiber mats of CsPO3, we hydrated them with steam to produce CsH2PO4. Unlike most electrospinning devices that use needles and syringes, our device uses rotating drums, which have demonstrated good scalability in the R&D setting and show promise for scaling to industrial sizes.We also comment on applying electrospinning approaches to other nanoscale ceramics, and the challenges in spinning commonly-avoided vicious materials.
Light-matter Interactions in Nanocrystalline Ceramics Near the Mie Scattering Limit: James Wollmershauser1; Serge Nakhmanson2; John Drazin3; Boris Feigelson1; Lukasz Kuna2; Edward Gorzkowski1; 1Naval Research Laboratory; 2University of Connecticut; 3Washington State University
Optical non-cubic (i.e., birefringent) ceramics with grain sizes around 40 nanometers sit at the edge of two regimes of light-matter interactions for visible light wavelengths. In ceramics with grain sizes smaller ~40 nanometers, the grain boundary periodicity is <10x smaller than the wavelength of incident light and Mie scattering can be neglected. However, for ceramics with grain sizes greater than ~40 nanometers, light-matter interactions can be described by a Rayleigh-Gans-Debye model developed by Apetz and van Bruggen. In this work, nanocrystalline alpha-alumina and ysz ceramics were synthesized via Environmentally Controlled Pressure Assisted Sintering (EC-PAS) and light-matter interactions were evaluated by characterizing the transmitted wave front quality and degree of diffuse scattering. Additionally a new mesoscale model will be discussed that may describe the observed behavior better than the traditional models.
11:20 AM Cancelled
Shape Evolution of CdSe/CdS Dot-in-Rods into Multi-tiered Pyramidal Nanocrystals: Growth Mechanisms and Optical Properties: Natalie Gogotsi1; Aditya Maan1; Christopher Murray1; 1University of Pennsylvania
CdSe-based nanocrystals have been widely studied for their simple and versatile synthesis, as well as their high degree of monodispersity, strong absorption and bright fluorescence which can be finely tuned by controlling the dimensions of the quantum dot core. Anisotropic hetero-structured nanocrystals, such as CdSe/CdS core/shell materials, can provide even greater enhancement and control of the optoelectronic properties, decreasing reabsorption effects and imparting fluorescence anisotropy not observed in spherical materials. Here we present the growth evolution of CdSe/CdS dot-in-rods into novel tiered pyramidal architectures, exhibiting large Stokes shifts and strong potentials as light harvesting materials. Key factors controlling the growth mechanism such as the initial nanocrystal characteristics and reaction conditions will be discussed along with the resulting structural and optical properties of the nanocrystals.