Solid oxide fuel cell having composition gradient between electrode and electrolyte

Abstract

A solid oxide fuel cell and method of making same is disclosed. An electrolyte layer of an oxide ion conductor material that may be specified by La1−aAaGa1−(b+c)BbCocO3 and an air electrode layer of an electron conductor material that may be specified by La1−dAdCoO3 are laminated, preferably with an intermediate layer of an electron and ion mixed conductor material that may be specified by La1−eAeGa1−(f+g)BfCogO3 interposed therebetween. The laminate may be sintered to integrate the layers, and may then subjected to a heat treatment to cause elements to diffuse through an interface between adjoining layers. The composition in each interface is thus continuously changed. Here, A may be at least one element selected from the group consisting of Sr and Ca, B may be at least one element selected from the group consisting of Mg, Al, and In, and 0.05≦a≦0.3, 0≦b, e≦0.3, 0≦c≦0.15, b+c≦0.3, 0≦d≦0.5, 0≦f≦0.15, 0.15<g≦0.3, and f+g≦0.3. The cell is free from cracks, distortion, delamination, and the increase in interface resistance under thermal stress during sintering is reduced. In addition, an increase in the reaction area in an air electrode results in an improved cell efficiency.

Dependencies are inferred from the claim text.