• We invented supercritical hydrothermal synthesis method for the synthesis of organic modified nanoparticles (NPs). Under the supercritical state, the organic molecules and metal salt aqueous solutions are miscible and water molecule works as an acid/base catalyst for the reactions. Organic-inorganic conjugate NPs can be synthesized under this condition. This hybrid NPs show high affinity with the organic solvent or the polymer matrix, which leads to fabricate the organic inorganic hybrid nanomaterials with the trade-off function (super hybird nanomaterials). These hybrid materials of polymer and ceramics fabricated with NPs achieve both high thermal conductivity and easy thin film flexible fabrication, namely trade-off function.

For example, by the surface modification of BN particles by supercritical method, affinity of BN and polymers could be improved, so that high BN content of hybrid materials, thus high thermal conductivity materials, could be synthesized. Also by dispersing high refractive index NPs like TiO2 or ZrO2 into polymers transparently, we can tune the refractive index of the polymers. CeO2 nanoparticles are expected to be used for high performance catalysts. To transfer those supercritical fluid nano technologies, a consortium was launched with more than 70 companies.

• Organicl compounds, such as liquid-crsytals, polymers, etc., can be hybridized with inorganic materials in atomic level, in particuar, with nanoparticles. Both of high effeciency of processing ease for the former and high possibilities of physical properties for the latter can be attained through the complete solution of trade-off characteristics. For example, this atomic-level hybridization technique makes inorganic nanoparticles active for the response like a liquid crystal. By using this method, we expect we can conduct effective collaborative research in medical fields.

• Nanoparticles and/or fine particles to be used for functional materials, such as semiconductor, photocatalysts, dielectric and/or piezoelectric materials, cosmetics, catalysts, etc., has been synthesized in liquid-phase. Their size, shape, composition, and structure have been <strong>precisely controlled</strong> along an expected usage. <strong>Tailor-made synthesis method</strong> has been provided for nanoparticles and/or fine particles the companies wish to use.

Until now, we have been supplying nanoparticles and/or fine particles of ITO (Indium Tin Oxides) as TCO, Bi based or Nb based particles for lead-free piezoelectric ceramics, perovskite-based oxides for dielectric materials etc. The gel-sol method as the main synthesis method for uniform particles makes the production cost reduced.

• Hybrid materials that show multi-functions of polymer and nanoparticles are expected to be used in future industries, and thus many research and development have been actively conducted. However, since the affinity of polymer and inorganic nanoparticles is very low, in most of the cases, properties of different materials are incompatible in the hybrid materials. To create the hybrid materials with incompatible multi-functions has been considered a difficult task.
• However, by using supercritical fluid technology, we have succeeded in making hybrid materials with incompatible multi-functions.

Now, variety of hybrid materials are being developed, including
・Transparent, flexible, high reflective index, and high fabricability,
・Flexible, high heat conductivity, low electric resistivity, and high fabricability.

• This group is engaged in basic and applied researches of "hydrides" for practical use in hydrogen energy system. The main subject is the exploration of advanced hydrogen storage materials which support hydrogen energy technologies such as fuel cells. Currently, we synthesize a wide variety of novel hydrides composed of lightweight metals with specific nano-structures using advanced techniques for crystal and electronic structure analyses. In addition to the hydrogen storage, we develop the wide research fields related to hydrides, such as fast lithium ionic conductors.

Besides the contributions in industrial progress through the material development for future hydrogen energy system and next-generation secondary battery, we positively provide technical assistance to organizations and companies concerned about our findings.

• This group is engaged in basic and applied researches of "hydrides" for practical use in hydrogen energy system. The main subject is the exploration of advanced hydrogen storage materials which support hydrogen energy technologies such as fuel cells. Currently, we synthesize a wide variety of novel hydrides composed of lightweight metals with specific nano-structures using advanced techniques for crystal and electronic structure analyses. In addition to the hydrogen storage, we develop the wide research fields related to hydrides, such as fast lithium ionic conductors.

Besides the contributions in industrial progress through the material development for future hydrogen energy system and next-generation secondary battery, we positively provide technical assistance to organizations and companies concerned about our findings.

• We are studying hydrogen embrittlement property of high strength steels from the aspects of both the effect of hydrogen on mechanical properties of high strength steels and hydrogen uptake behavior in corrosive environments. The topics of our study includes clarification of mechanism of hydrogen embrittlement of various steels, investigation of hydrogen entry caused by corrosion using electrochemical techniques, hydrogen visualization, proposing evaluation methods for hydrogen embrittlement property and so forth.

Collaborative research in the field of hydrogen embrittlement, for example, hydrogen embrittlement properties of high strength steels and the effects of metallographic structure and hydrogen traps, proposal of evaluation methods for hydrogen embrittlement property for some specific steel and for parts with specific shape, development of novel hydrogen visualization techniques.

• Our focus is on the development of solid-state-ionics materials to be used for a variety of energy conversion systems. To further improve the performance of fuel cells and lithium batteries, novel ionic conductors and mixed conductors with high ionic conductivity and chemical stability are highly demanded. We have been developing such the materials based on defect chemistry and thermodynamics of ceramics, and trying to apply those materials to actual energy conversion devices.

To date, a hydrogen production system utilizing oxygen permeable membranes and an all-solid-state battery have been prepared.