Author
Yoshihiko Sadaoka
Other affiliations: Kyushu University
Bio: Yoshihiko Sadaoka is an academic researcher from Ehime University. The author has contributed to research in topics: Thermal decomposition & Heteronuclear molecule. The author has an hindex of 40, co-authored 270 publications receiving 6554 citations. Previous affiliations of Yoshihiko Sadaoka include Kyushu University.
Papers published on a yearly basis
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TL;DR: In this article, several useful methods for improving the characteristics of humidity sensors based on polymers are proposed, such as cross-linking of hydrophilic polymers or formation of interpenetrated polymer networks with a hydrophobic polymer.
Abstract: Studies on humidity sensors fabricated with organic polymers for the last 10 years are reviewed. Several useful methods for improving the characteristics of humidity sensors based on polymers are proposed. In the case of a resistive-type sensor, cross-linking of hydrophilic polymers or formation of interpenetrated polymer networks with a hydrophobic polymer makes the hydrophilic polymers durable at high humidities. Graft polymerization is another method of preparing water-resistive humidity sensors. In the case of capacitive-type sensors, cross-linking is also useful to modify the hydrophobic polymer to produce a sensor with small hysteresis, high selectivity and high sensitivity.
415 citations
TL;DR: In this paper, the activation energy and conductivity for lanthanoid silicates of the Ln10(SiO4)6O3 solid solution series and related compounds were investigated.
Abstract: Ionic conductivities have been investigated for lanthanoid silicates of the Ln10(SiO4)6O3 solid solution series and related compounds. The activation energy and conductivity at 500 °C were estimated to be 69 kJ mol–1 and 1.8 × 10–4 S cm–1 for La10(SiO4)6O3 and 71 kJ mol–1 and 1.5 × 10–4 S cm–1 for Nd10(SiO4)6O3. The a and c lattice constants of the hexagonal phase decreased with decreasing radius of the Ln3+ ion for Ln10(SiO4)6O3(Ln = La, Nd, Sm, Gd and Dy). The activation energy increased and the conductivity decreased when Ln3+ ions with smaller ionic radii were used. The sole carrier in these materials is the O2– ion.
334 citations
TL;DR: In this paper, a lithium salt (Li 3 PO 4 or Li 3 BO 3 ) was added to LiTi 2 (PO 4 ) 3 to obtain a dense pellet of the phosphate.
242 citations
TL;DR: In this article, the perovskite-type oxide powders used for the preparation of the thick films have been tested in laboratory, in environments with different gases (CO and NO 2 ) in dry and wet air.
Abstract: Thick films of LaFeO 3 and SmFeO 3 were fabricated by screen-printing technology on alumina substrates with comb-type Au electrodes. The perovskite-type oxide powders used for the preparation of the thick films have been prepared by the thermal decomposition at 700°C of hexacyanocomplexes, Ln[Fe(CN) 6 ] · n H 2 O. These powders are ultrafine, homogeneous, and free of intragranular pores. The films have been fired at different temperatures in the 750–1000°C range, in N 2 and air atmospheres. The gas-sensitive electrical response of the thick films have been tested in laboratory, in environments with different gases (CO and NO 2 ) in dry and wet air. For field tests, the prototype sensors have been placed beside a conventional station for environmental monitoring. The electrical response of the thick films has been compared with the results of the analytical instruments for environmental monitoring. The same trend was observed for both systems, with very promising results.
221 citations
TL;DR: In this paper, the conductivity at 773 K was 2.3 × 104 S cm−1 for Nd10(SiO4)6O3 (Ln = La, Nd, Sm, Gd and Nd).
Abstract: Electrical properties were investigated for lanthanoid-silicates of Ln10(SiO4)6O3(Ln = La, Nd, Sm, Gd and Nd). The conductivity at 773 K was 2.3 × 104 S cm−1 for Nd10(SiO4)6O3. The sole carrier is the O2− ion, which was determined using an O2 gas concentration cell.
203 citations
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TL;DR: In this article, the authors provide a background overview and discuss the state of the art, ion-transport mechanisms and fundamental properties of solid-state electrolyte materials of interest for energy storage applications.
Abstract: Solid-state electrolytes are attracting increasing interest for electrochemical energy storage technologies. In this Review, we provide a background overview and discuss the state of the art, ion-transport mechanisms and fundamental properties of solid-state electrolyte materials of interest for energy storage applications. We focus on recent advances in various classes of battery chemistries and systems that are enabled by solid electrolytes, including all-solid-state lithium-ion batteries and emerging solid-electrolyte lithium batteries that feature cathodes with liquid or gaseous active materials (for example, lithium–air, lithium–sulfur and lithium–bromine systems). A low-cost, safe, aqueous electrochemical energy storage concept with a ‘mediator-ion’ solid electrolyte is also discussed. Advanced battery systems based on solid electrolytes would revitalize the rechargeable battery field because of their safety, excellent stability, long cycle lives and low cost. However, great effort will be needed to implement solid-electrolyte batteries as viable energy storage systems. In this context, we discuss the main issues that must be addressed, such as achieving acceptable ionic conductivity, electrochemical stability and mechanical properties of the solid electrolytes, as well as a compatible electrolyte/electrode interface. This Review details recent advances in battery chemistries and systems enabled by solid electrolytes, including all-solid-state lithium-ion, lithium–air, lithium–sulfur and lithium–bromine batteries, as well as an aqueous battery concept with a mediator-ion solid electrolyte.
2,749 citations
TL;DR: A detailed study of the structure of Perovskites and their properties in the context of a reducing Atmosphere andHydrogenation and Hydrogenolysis Reactions 2006 shows that the structure and properties of these minerals have changed little in the intervening years.
Abstract: II. Structure of Perovskites 1982 A. Crystal Structure 1982 B. Nonstoichiometry in Perovskites 1983 1. Oxygen Nonstoichiometry 1983 2. Cation Nonstoichiometry 1984 C. Physical Properties 1985 D. Adsorption Properties 1986 1. CO and NO Adsorption 1986 2. Oxygen Adsorption 1987 E. Specific Surface and Porosity 1987 F. Thermal Stability in a Reducing Atmosphere 1989 III. Acid−Base and Redox Properties 1990 A. Acidity and Basicity 1990 B. Redox Processes 1991 1. Kinetics and Mechanisms 1992 2. Reduction−Oxidation Cycles 1993 C. Ion Mobility 1993 1. Oxygen Transport 1993 2. Cation Transport 1994 IV. Heterogeneous Catalysis 1995 A. Oxidation Reactions 1995 1. CO Oxidation 1995 2. Oxidation of Hydrocarbons 1996 B. Pollution Abatement 2001 1. NOx Decomposition 2001 2. Exhaust Treatment 2002 3. Stability 2004 C. Hydrogenation and Hydrogenolysis Reactions 2004 1. Hydrogenation of Carbon Oxides 2004 2. Hydrogenation and Hydrogenolysis Reactions 2006
2,253 citations
TL;DR: In this paper, a review of the proton conductivity in materials and the elements of proton conduction mechanisms are discussed with a special emphasis on proton chemistry, including structural reorganization and diffusional motion of extended moieties.
Abstract: In this review the phenomenon of proton conductivity in materials and the elements of proton conduction mechanismsproton transfer, structural reorganization and diffusional motion of extended moietiesare discussed with special emphasis on proton chemistry. This is characterized by a strong proton localization within the valence electron density of electronegative species (e.g., oxygen, nitrogen) and self-localization effects due to solvent interactions which allows for significant proton diffusivities only when assisted by the dynamics of the proton environment in Grotthuss and vehicle type mechanisms. In systems with high proton density, proton/proton interactions lead to proton ordering below first-order phase transition rather than to coherent proton transfers along extended hydrogen-bond chains as is frequently suggested in textbooks of physical chemistry. There is no indication for significant proton tunneling in fast proton conduction phenomena for which almost barrierless proton transfer is suggest...
2,039 citations
TL;DR: Insight is provided into the physical parameters affecting the diffusion process, to allow for more efficient and target-oriented research on improving solid-state ion conductors.
Abstract: This Review is focused on ion-transport mechanisms and fundamental properties of solid-state electrolytes to be used in electrochemical energy-storage systems. Properties of the migrating species significantly affecting diffusion, including the valency and ionic radius, are discussed. The natures of the ligand and metal composing the skeleton of the host framework are analyzed and shown to have large impacts on the performance of solid-state electrolytes. A comprehensive identification of the candidate migrating species and structures is carried out. Not only the bulk properties of the conductors are explored, but the concept of tuning the conductivity through interfacial effects—specifically controlling grain boundaries and strain at the interfaces—is introduced. High-frequency dielectric constants and frequencies of low-energy optical phonons are shown as examples of properties that correlate with activation energy across many classes of ionic conductors. Experimental studies and theoretical results are...
1,567 citations
1,444 citations