ACerS 2017 Richard M. Fulrath Award Session
Akitoshi Hayashi, Osaka Prefecture University
Development of ion-conducting glasses for solid-state batteries
Solid-state rechargeable batteries have attracted much attention because of their high safety, large energy density, long-cycle performance, and versatile geometry. A key material to realize those batteries is a superior inorganic solid electrolyte. Sulfide solid electrolytes having high Li+ ion conductivity of over 10-2 S cm-1 have been developed, and the conductivity of inorganic lithium ion conductors has already reached to the same level of the conductivity of organic liquid electrolytes applied to commercially available lithium-ion batteries. We have prepared sulfide glass electrolytes in a variety of systems by not only rapid quenching but also mechanical milling; the latter technique has a merit of room-temperature process and direct preparation of glass particles favorable for solid-state battery application. In addition, a glass electrolyte is useful as a precursor for precipitating a metastable phase with superionic conduction. Crystalline Li7P3S11 which is difficult to prepare by conventional solid state reaction has been precipitated as a metastable phase by careful heat-treatment of a mother glass. Cubic Na3PS4 with the highest Na+ ion conductivity in sulfide systems is also prepared in a same manner. Mechanical properties such as good formability and appropriate Young’s modulus are also important to secure a close electrode-electrolyte solid-solid interface during charge-discharge cycling in all-solid-state batteries. The sulfide glasses such as Li3PS4 and Na3PS4 show a small Young’s modulus as inorganic ceramics. Formation of favorable and large contact areas between electrode and electrolyte is achieved by amorphous sulfide electrolyte coating on electrode particles via gas-phase or liquid-phase techniques. The electrolyte coatings have a merit of reducing the amount of electrolyte in the electrode layer, which results in an increase of energy density of the batteries.
Chie Kawamura, Taiyo Yuden Co., Ltd.
Synthesis of High crystalline and fine BaTiO3 Powder for Thinner Ni-MLCCs Via Solid State Root
To realize further miniaturization and higher capacitance of multi-layer ceramic capacitors, BaTiO3 (BT) powders with smaller grains (<200nm), with highest possible crystallinity are required. Solid state synthesis of ceramic powder is regarded as often considered as traditional and trivial. By rationalizing the preparation process of the starting mixture, together with the advent of ultrafine material powders on the market, solid state route is now capable to prepare fine particle while keeping its high crystalline. Therefore we studied to improve solid state processes of BT powder and achieved the synthesis of finer grains, narrower particle size distribution, and higher tetragonality.
Jon Ihlefeld, Sandia National Lab
New Functionality from Reconfigurable Ferroelastic Domains in Ferroelectric Films
Regulating the transport of energy is typically achieved utilizing many specialized material classes, embodiments, and integration schemes dependent upon the form of energy to be controlled. In this lecture, I will present and discuss how a single class of materials, functional ferroelectric oxides, can be used to manipulate phononic and photonic. These approaches can be achieved through utilizing reconfigurable coherent interfaces, ferroelastic domain walls, as phonon and phonon-polariton scattering interfaces. Utilizing compositional heterostructure thin films in the lead zirconate titanate family of ferroelectrics, materials with engineered domain wall densities can be prepared where their domain wall motion is facile, despite mechanical constraints imposed by the underlying substrate. I will show how reconfiguring these domain walls enables active regulation of phonon transport and also how these domain walls can be used to modify the transport of phonon-polaritons responsible for optical reflectivity.
Hideki Tanaka, Shoei Chemical, Inc.
Development of Mass Production of Ni-nanopowder for the Internal Electrode of MLCC by DC Thermal
Recently, great attention has been paid to nanoparticle as promising next generation elements in electronics, energy and environmental applications. Thermal plasma processes have been used for the preparation of various kinds of nanoparticles of metals and ceramics because of its advantages, including, high temperature, high enthalpy, extremely high heating and quenching rates, giving rise to high-crystallinity nanoparticles. For industrial applications of such nanoparticles, it is desired to develop a cost-effective method for the mass production of nanoparticles. However, while thermal plasma processes have a great potential for such a technological application, the mass production of nanoparticles using thermal plasmas have been thought to be extremely difficult under industrial scale due to low controllability in the grain growth process. In addition, high operating costs and wide particle size distribution have been the decisive bottleneck for mass production by thermal plasma. We have developed a unique method to synthesize nanopowders at high production rates using DC thermal plasma. Our work has focused on the overall process improvements that product quality of the fine Ni-powders, especially surface property, particle morphology and particle size distribution, increased productivity to 600-tonne per year of Ni-powder, and reduced production cost.
Klaus Van Benthem, University of California, Davis
Do Fields Matter? — Microstructure Evolution in Ceramic Oxides
The application of electric fields enables accelerated densification during field assisted sintering. Although such techniques are already employed for the synthesis of a variety of microstructures with unique properties, a fundamental understanding of the atomic-scale mechanisms for grain boundary formation and subsequent migration in the presence of electrostatic potentials remains mostly absent from the literature. We have designed experiments to focus specifically on the effects of applied electrostatic fields on consolidation and grain growth. In-situ transmission electron microscopy experiments have revealed that non-contacting electric fields can cause accelerated densification in YSZ, while enhanced grain growth was observed in dense MgAl2O4 ceramics. Results presented in this presentation will focus on recent discoveries that electric fields can alter the atomic structure of equilibrium grain boundary configurations in SrTiO3 bicrystals.