Hisaaki Gyoten

Development of film-shaped thermoelectric materials for thermoelectric modules

Film-shaped thermoelectric materials have been prepared for thermoelectric modules for cooling or electricity generation. Flash evaporation and casting are adopted for preparing film-shaped p-, n-type (Bi,Sb)2(Te,Se)3 materials. The chemical characteristics and the thermoelectric properties of these samples have been investigated. By controlling the preparation temperature or selecting the impurities, film-shaped thermoelectric materials, comparable in properties with bulk-shaped sintered materials, are obtained. The thermoelectric power factor of the n-type (6-7Â [mu]m) film sample, prepared by the flash evaporation method, is 30Â [mu]WÂ cm-1K2. In addition, that of the p-type (0.5-0.7Â [mu]m) film sample , prepared by the casting method with added impurities, is 40Â [mu]WÂ cm-1K2.

Effect of Electrolyte Polymer Acidity on Platinum Degradation in MEAs

We fabricated MEAs having the EW200 or EW1000 electrolyte in the catalyst layer. The potential cycle test (square-wave potential cycling between 0.6-1.0 V with a pulse width of 3 s) was performed for these MEAs to evaluate the ECA change from CVs. It was revealed that the ECA decrease of the EW200 MEA was 1.6 times faster than that of the EW1000 MEA. It was revealed that the onset shift of the platinum oxidation potential, caused by the sulfonic acid group adsorption [6], depended on the electrolyte EW. The shifts were 0.7 V and 0.8 V for the EW1000 MEA and the EW200 MEA, respectively. These differences would presumably affecte on the ECA change rate.