Kenji Tamamitsu

Highly clear and transparent nanoemulsion preparation under surfactant-free conditions using tandem acoustic emulsification.

A new technique for the preparation of a highly clear and transparent emulsified aqueous solution containing immiscible monomer droplets with diameters of a few tens of nanometres under surfactant-free conditions using tandem acoustic emulsification is described. Highly conductive transparent polymer films were successfully prepared from such an emulsified solution.

Capacitor Properties and Pore Structure of Single- and Double-Walled Carbon Nanotubes

The correlation between capacitance and the structure of carbon nanotubes (CNTs) was revealed. The electrochemical behaviors of single- and double-walled CNTs were characteristic due to the electrochemical doping mechanism of semiconducting nanotubes, which are amphoteric and can be doped by both donors and acceptors. The capacitance and the sheet conductance of CNTs, as capacitor electrodes were dependent on their porous and electronic structure. High specific capacitance was obtained for uncapped single-walled CNTs having inner micropores with a diameter of < 1 nm.

High-Voltage Asymmetric Electrochemical Capacitor Based on Polyfluorene Nanocomposite and Activated Carbon

An asymmetric electrochemical capacitor based on polyfluorene/carbon nanocomposite as positive electrode and activated carbon as negative electrode with nonaqueous electrolyte of 1 M tetraethylammonium tetrafluoroborate/propylene carbonate was investigated. From a galvanostatic charge-discharge test, the asymmetric capacitor test cell exhibited cell voltage as high as 3.2 V because of the high redox potential of the positive electrode (∼ 1.1 V vs Ag/Ag + ). Specific capacitance obtained for the test cell was 34 F g -1 (per electrode mass). The maximum energy density of the test cell was 47 Wh kg -1 (per electrode mass), which was two times higher than that of typical double-layer capacitors based on activated carbon/activated carbon electrodes.

Advanced hybrid capacitor with lithium titanium oxide for automobile

We have developed a next generation capacitor named Nano-hybrid capacitor (NBC), which uses a completely new lithium titanium oxide (LTO)-based negative electrode material comprising of nano-crystalline LTO grafted onto carbon nano-fibers (nano-LTO/CNF composite). The nano-LTO/CNF composite is simply prepared by using “Nano-hybrid technique”. The NBC has realized higher energy performance than electric double layer capacitor (EDLC) as a conventional capacitor, maintaining a good power performance as high as the EDLC.