ETEM Techniques for Development of Energy Related New Materials
Abstract: Recently, various power sources, such as fuel cells, rechargeable batteries, capacitors, have been developed and put into practical use. These power sources employ the chemically synthesized nanomaterials. Since the fine structures of these nanomaterials are closely related to their performance，it is essential to analyze the structures in detail. TEM is one of the most powerful and useful tools in the studies of these nanomaterials. However, most of these nanomaterials are extremely sensitive to the electron beam irradiation and easily change their structures as soon as the electron dose exceeds the limit. Therefore the highest attention must be paid in the structural characterization of these nanomaterials using TEM. In this paper, an example of the structure analyses of a chemically synthesized Pt/CB electrocatalyst for the polymer electrolyte fuel cell (PEFC) using TEM and the observation conditions for minimizing the electron beam irradiation damage are reported. In addition, in situ TEM observation of the degradation process of the Pt/CB electrocatalyst in the highly-humidified and not-humidified air atmospheres are reported as an application of ETEM technique. An ETEM based on a conventional analytical TEM and a specimen heating holder employed a gas injector were used in the study.
Key words: Environmental TEM, in situ observation, gas reaction, composite nanomaterials, electron irradiation damage