東京大学 · 材料科学
Yamada教授の研究室は、金属有機フレームワーク(MOF)や一维性配位子ポリマーを基盤とした機能性材料の設計・創出を柱としています。特に、プロトン伝導性を示す配位子ポリマーの開発や、酸性官能基の導入による高効率な燃料電池用電解質の構築に注力しています。また、熱安定性に優れた金属酸化物型MOFをリチウムイオン電池の正極材料として応用する研究も進めています。これらの研究は、次世代エネルギー変換・貯蔵デバイスの実現に向けた基盤技術の確立をめざしています。
Figures are computed from collected data and may differ slightly.
Proton conductive materials become important for their utility to electrolytes of fuel cells or sensors. The proton conductivity of a one-dimensional coordination polymer, ferrous oxalate dihydrate, was evaluated and found to show 1.3 mS cm(-1) at ambient temperature. The proton conductivity of this compound is extremely high at ambient temperature without any strong acidic group, and this result is suggestive of new proton conductive materials consisting of coordination polymers.
A noncoordinating hydroxyl group was introduced into a metal-organic framework (MOF) by a procedure involving a protection, complexation, and deprotection (PCD) reaction sequence, and the crystal structure of a novel MOF, [Zn(dhybdc)(bpy)] x 4 DMF (1), was determined. 1 did not have an interpenetrated structure. The three-dimensional pores had large apertures. Results showed that the PCD method is a novel synthetic method for the introduction of various functional groups into MOFs.
Abstract Proton-conductive electrolytes are key materials in fuel cells. We introduced acidic functional groups into a porous coordination polymer (PCP), or metal–organic framework (MOF), and constructed proton-conductive PCP/MOFs. To achieve this, a novel synthetic method for introducing acidic groups in PCP/MOF was invented. The proton conductivities of various PCP/MOF materials were investigated by AC impedance spectroscopy, and some of the materials showed high proton conductivity up to 8 ×
MIL-101(Fe) was investigated as a cathode material of lithium ion batteries. A battery test reveals that MIL-101(Fe) shows a charge and discharge capacitance of 110 mA h g<sup>-1</sup>. It also showed reversible charge and discharge cycles and uptake of 0.62 Li/Fe after 100 cycles, which is the highest loading amount ever reported for the carboxylic MOFs. It also operates in the temperature range up to 350 °C and showed a good high thermal stability.
Abstract One-dimensional (1D) coordination polymers, M(dhbq)·nH2O (M = Mg, Mn, Co, Ni, and Zn, H2(dhbq) = 2,5-dihydroxy-1,4-benzoquinone, n = 2, 2.5, or 3), were synthesized and their structures were investigated using the Rietveld refinement method. They have 1D structure and were isostructural. From water uptake measurements, thermogravimetry, and elemental analysis, new 2.5 hydrate states were discovered. The proton conductivity of M(dhbq) was found to depend on the metal species and the quan
A large Seebeck coefficient (<i>S</i> <sub>e</sub>) of 1.9 mV K<sup>-1</sup> was recorded for the I<sup>-</sup>/I<sub>3</sub> <sup>-</sup> thermocell by utilizing the host-guest complexation of hexakis(2,3,6-tri-<i>O</i>-methyl)-α-cyclodextrin (Me<sub>18</sub>-α-CD) with the oxidized iodide species. The thermocell measurement and UV-vis spectroscopy unveiled the formation of an Me<sub>18</sub>-α-CD-pentaiodide (I<sub>5</sub> <sup>-</sup>) complex, which is in remarkable contrast to the triiodide
The high Seebeck coefficient of an I–/I3– thermocell was achieved by introducing host molecule PEGylated α-cyclodextrin (TEG-α-CD), which showed thermally induced phase transition. The host captures I3– at the cold side of the thermocell, which increased Se up to +2.4 mV/K. Notably, the maximum Se value of +4.2 mV/K was observed in the temperature range between 31 and 37 °C, which was achieved as a consequence of the phase transition between a hydrophilic phase to a hydrophobic phase. At the low
We present the solvothermal syntheses, X-ray crystal structures, and gas sorption properties of a series of zinc−dicarboxylate−polypyridine where the dicarboxylate is 1,4-benzenedicarboxylate, 4,4′-biphenyldicarboxylate, or sulfone-4,4′-biphenyldicarboxylate and the polypyridine is bipyridine or 1,4-bis(4-pyridylethynyl)benzene. The structures consist of hierarchical two-, three-, and four-blade dimer or trimer nodes which generate the square or triangular topologies of the metal-carboxylate lay
Open papers in the app to read, cite, and organize with AI.