Patent ID: 7033690

Claim:
A solid oxide fuel cell comprising an air electrode layer, a fuel electrode layer, and a solid electrolyte layer interposed between said air electrode layer and said fuel electrode layer, wherein said solid electrolyte layer comprises a first electrolyte layer which is made of a lanthanide-gallate oxide and has a first ionic transference number and a first total electric conductivity, and a second electrolyte layer which is made of a lanthanide-gallate oxide and has a second ionic transference number smaller than said first ionic transference number and a second total electric conductivity larger than said first total electric conductivity; said air electrode layer is laminated onto one side of said solid electrolyte layer; said fuel electrode layer is laminated onto the other side of said solid electrolyte layer; said first and second electrolyte layers are made of a compound represented by general formula (1): Ln 1−a A a Ga 1−(b+c) B b Co c O 3 , wherein Ln is lanthanide rare earth metals; wherein A is one or more kinds of Sr, Ca, and Ba; B is one or more kinds of Mg, Al, and In; a is in the range from 0.05 to 0.3; b is in the range from 0 to 0.3; c is in the range from 0 to 0.2; and (b+c) is in the range from 0.025 to 0.3; an amount of Co in said first electrolyte layer is 0%≦Co≦80% with respect to an amount of Co in said second electrolyte layer; and a thickness of said second electrolyte layer is larger than a thickness of said first electrolyte layer.