Toshihiko Saitoh

Degradation phenomena in the cathode of a solid oxide fuel cell with an alloy separator

A study is made of the cathode degradation phenomena in a solid oxide fuel cell that uses an alloy separator. Under the action of the discharge current, chromium diffuses from the alloy to the cathode and moves to the cathode/electrolyte interface. The cathode polarization increases in correlation with the intensity of chromium at the cathode/electrolyte interface. The increase in cathode polarization by the discharge current is due to chromium filling the pores at the cathode/electrolyte interface. This restricts diffusion of oxygen gas and decreases the number of electrode reaction sites. Chromium displacement at the cathode/electrolyte interface appears to be caused by the decrease in oxygen activity at the cathode/electrolyte interface.

A study of heat and material balances in an internal-reforming molten carbonate fuel cell

A study is made of the heat and material balances in internal-reforming, molten carbonate fuel cells. A 5 kW class, indirect internal-reforming molten carbonate fuel cell stack together with a 10 kW class, direct internal-reforming molten carbonate fuel cell stack have been assembled and tested to evaluate the performance, and to obtain basic data on the material and heat balances, in order to assist system design. The input and output heat flux of the stacks are obtained independently, and are in good agreement. Using these procedures, it will be possible to improve the design of internal-reforming, molten carbonate fuel cell systems for co-generation.

Surface treatment of alloy separator in a planar-type solid oxide fuel cell

Abstract In the process of improving the performance of planar-type solid oxide fuel cells it is found necessary to apply an appropriate surface treatment to the alloy separator that can diffuse chromium to the cathode. Cathode polarization shows a correlation with the intensity of the chromium. With heat treatment and polishing to remove the surface oxide layer, the amount of chromium diffusing from the alloy is suppressed and cell performance is raised. Accordingly, a 150 mm2 single cell has been operated stably for about 3000 h.

Ion conductive material for secondary battery

A secondary battery is comprised of a positive electrode having a material intercalating alkali earth metal ions reversibly, a negative electrode having a carbon composition intercalating those ions reversibly and an electrolyte having an organic solvent and a solute. The solute includes an alkali earth metal salt. The organic solvent is selected from a group comprising ethylene carbonate (EC), dimethyl carbonate (DMC) and vinylene carbonate (VC). The carbon composition is selected from a group comprising coke, refined coke with 99% or more purity, organic compound produced by calcined cellulose, graphite and glassy carbon.