Solid Oxide Fuel Cell: Oxide Ion and Proton Conductions

Abstract

“Hydrogen” (hydrogen molecule) has attracted much industrial interest as future energy resource. Fuel cell is the efficient system that produces the electric energy from hydrogen molecule. Solid oxide fuel cell has been much expected, due to high efficiency of power generation. Solid oxide fuel cell is classified into oxide ion conducing type and proton conducting type. In oxide ion conducting type, oxide ion migrates through oxygen vacancy. Oxide ion forms covalent bonding with counter cations. Oxide ion conductivity can be controlled by changing dopant. In proton conducting type, proton forms covalent bonding with oxygen atoms. In diagonal path, OH and OHO bonds are alternately formed. During proton conduction, the proton pumping is combined. It implies that proton is pumped towards the square centre through OH conduction. The conflict with oxide ion conduction during proton conduction is also discussed. Finally, the mismatch of the calculated activation energy with AC impedance measurement is mentioned.