Kenji Mizoguchi

Bio: Kenji Mizoguchi is an academic researcher from Tokyo Metropolitan University. The author has contributed to research in topics: Electron paramagnetic resonance & Polyacetylene. The author has an hindex of 22, co-authored 130 publications receiving 1762 citations. Previous affiliations of Kenji Mizoguchi include Chuo University & Centre national de la recherche scientifique.

Nanocomposite of Polyaniline and Na+-Montmorillonite Clay

Abstract: Nanocomposites of conducting polyaniline (PAN) with inorganic Na+−montmorillonite (MMT) clay were synthesized by the emulsion polymerization method. The dodecylbenzenesulfonic acid (DBSA) was used for both dopant and emulsifier. Analyses of X-ray diffraction patterns demonstrated that conducting PAN-DBSA was intercalated between inorganic clay layers at the nanoscale level (<10 A). We observed that the clay induced more disordered state in PAN-DBSA/clay nanocomposites. From the temperature-dependent dc conductivity [σdc(T)] experiments, we investigated charge transport mechanism of the PAN-DBSA and PAN-DBSA/clay systems. The interaction between the intercalated PAN-DBSA and the clay layers was observed by FT-IR spectra. The results of differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) showed the improved thermal stability of the nanocomposite materials. The σdc of these systems was 101−10-2 S/cm at room temperature, varying with dopant molar ratio. The σdc(T) of the nanocomposite...

Spin dynamics in the conducting polymer, polyaniline.

Abstract: The frequency dependences of both proton NMR ${T}_{1}$ and ESR linewidth in polyaniline give evidence for quasi-1D spin diffusion. The on-chain diffusion rate, ${\mathit{D}}_{\mathrm{\ensuremath{\parallel}}}$, is independent on the protonation level, while the transverse diffusion, ${D}_{\ensuremath{\perp}}$, exhibits a sudden drop at the percolation threshold. This behavior confirms the conducting-island picture, but it is concluded that a given conducting island just consists of a single conducting chain. The room-temperature data show a strong correlation between spin dynamics and transport properties, and suggest that conductivity is governed by interchain hoppings.

Synthesis and charge/discharge properties of polyacetylenes carrying 2,2,6,6-tetramethyl-1-piperidinoxy radicals.

Abstract: The 2,2,6,6-tetramethyl-1-piperidinoxy (TEMPO)-containing acetylenic monomers HCCC6H3-p,m-(CONH-4-TEMPO)2 (1), HCCC6H3-p,m-(COO-4-TEMPO)2 (2), (S,S,S,S)-HCCC6H3-p,m-[CO-NHCH{COO-(4-TEMPO)}CH2COO-(4-TEMPO)]2 (3), (S,S)-HCCC6H4CO-NHCH{COO-(4-TEMPO)}CH2COO-(4-TEMPO) (4), HCCC6H4-p-OCO-4-TEMPO (5), HCCCH2C(CH3)(CH2OCO-4-TEMPO)2 (6), HCCCH2NHCO-4-TEMPO (7), and HCCCH2OCO-4-TEMPO (8) were polymerized to afford novel polymers containing the TEMPO radical at high densities. Monomers 1, 3–6, and 8 provided polymers with average molecular weights of 10 000–136 500 in 62–99 % yield in the presence of a rhodium catalyst, whereas monomers 2 and 7 gave insoluble polymers in 100 % yield. The formed polymers were thermally stable up to approximately 274 °C according to thermogravimetric analysis (TGA). All the TEMPO-containing polymers demonstrated reversible charge/discharge processes, whose discharge capacities were 21.3–108 A h kg−1. In particular, the capacity of poly(1)-, poly(4)-, and poly(5)-based cells reached 108, 96.3, and 89.3 A h kg−1, respectively, which practically coincided with their theoretical values.

Synthesis, Characterization, and Charge/Discharge Properties of Polynorbornenes Carrying 2,2,6,6-Tetramethylpiperidine-1-oxy Radicals at High Density

Abstract: TEMPO-containing norbornene monomers 1−8 (TEMPO = 2,2,6,6-tetramethylpiperidine-1-oxy) were synthesized and polymerized via ring-opening metathesis using a ruthenium−carbene catalyst. The TEMPO moiety did not inhibit the polymerization, and the monomers gave corresponding polymers in good to high yields. Poly(2) and poly(3) were soluble in common solvents and possessed high molecular weight, while other polymers were insoluble. The resulting polymers were thermally stable up to ca. 240 °C according to TGA measurements in air. In the case of poly(1)−poly(3), the charge/discharge capacities of the polymer-based cells were largely dependent on the spatial arrangement of the two TEMPO moieties on each repeating unit. Quite interestingly, the capacity of the poly(2)-based cell reached its theoretical value (109 A h/kg), and a large capacity (>90 A h/kg) was retained even at high current densities up to 6 A/g, indicating the possibility of very fast charging (within 1 min). The cells utilizing the present polym...

Organic Electrode Materials for Rechargeable Lithium Batteries

Abstract: Organic compounds offer new possibilities for high energy/power density, cost-effective, environmentally friendly, and functional rechargeable lithium batteries. For a long time, they have not constituted an important class of electrode materials, partly because of the large success and rapid development of inorganic intercalation compounds. In recent years, however, exciting progress has been made, bringing organic electrodes to the attention of the energy storage community. Herein thirty years' research efforts in the field of organic compounds for rechargeable lithium batteries are summarized. The working principles, development history, and design strategies of these materials, including organosulfur compounds, organic free radical compounds, organic carbonyl compounds, conducting polymers, non-conjugated redox polymers, and layered organic compounds are presented. The cell performances of these materials are compared, providing a comprehensive overview of the area, and straightforwardly revealing the advantages/disadvantages of each class of materials.

Conjugated dicarboxylate anodes for Li-ion batteries.

Abstract: Present Li-ion batteries for portable electronics are based on inorganic electrodes. For upcoming large-scale applications the notion of materials sustainability produced by materials made through eco-efficient processes, such as renewable organic electrodes, is crucial. We here report on two organic salts, Li2C8H4O4 (Li terephthalate) and Li2C6H4O4(Li trans-trans-muconate), with carboxylate groups conjugated within the molecular core, which are respectively capable of reacting with two and one extra Li per formula unit at potentials of 0.8 and 1.4 V, giving reversible capacities of 300 and 150 mA h g-1. The activity is maintained at 80 °C with polyethyleneoxide-based electrolytes. A noteworthy advantage of the Li2C8H4O4 and Li2C6H4O4 negative electrodes is their enhanced thermal stability over carbon electrodes in 1 M LiPF6 ethylene carbonate-dimethyl carbonate electrolytes, which should result in safer Li-ion cells. Moreover, as bio-inspired materials, both compounds are the metabolites of aromatic hydrocarbon oxidation, and terephthalic acid is available in abundance from the recycling of polyethylene terephthalate.

Polymer-Based Organic Batteries

Abstract: The storage of electric energy is of ever growing importance for our modern, technology-based society, and novel battery systems are in the focus of research. The substitution of conventional metals as redox-active material by organic materials offers a promising alternative for the next generation of rechargeable batteries since these organic batteries are excelling in charging speed and cycling stability. This review provides a comprehensive overview of these systems and discusses the numerous classes of organic, polymer-based active materials as well as auxiliary components of the battery, like additives or electrolytes. Moreover, a definition of important cell characteristics and an introduction to selected characterization techniques is provided, completed by the discussion of potential socio-economic impacts.

Carbon Nanotube−Inorganic Hybrids

Abstract: 3.1.1. Covalent Interactions 1355 3.1.2. Noncovalent Interactions 1356 3.1.3. π-π Stacking 1356 3.1.4. Electrostatic Interactions 1357 3.2. In Situ Synthesis Directly on the CNT Surface 1358 3.2.1. Electrochemical Techniques 1358 3.2.2. Sol-Gel Process 1361 3.2.3. Hydrothermal and Aerosol Techniques 1363 3.2.4. Gas-Phase Deposition 1364 3.3. Comparison of Synthesis Techniques 1368 4. Properties and Potential Applications of CNT-Inorganic Hybrids 1368