A thin tubular self-supporting electrode for solid oxide electrolyte electrochemical cells

Claim 1

A method of making a self-supporting air electrode tube characterized by the steps: (1) dry-mixing MnO₂, CaCO₃ and La₂O₃ powder in an amount effective to provide a calcium-doped LaMnO₂ material after calcining; (2) pressing the powder into a shape; (3) calcining the pressed shape at a temperature of from 1,300°C to 1,700°C; (4) crushing the calcined shape to provide calcined particles of calcium-doped LaMnO₃ having a particle size range of from 0.1 micrometer to 105 micrometers; (5) mixing the calcined particles with a decomposable cohesion agent, a decomposable pore-forming agent, and a water-soluble binder, to provide a formable composition, where the calcined particles constitute from 90 weight% to 95 weight% of the composition; (6) forming the composition into a thin tubular shape; and (7) heating the tube at from 1,300°C to 1,700°C to vaporize the binder, cohesion agent, and pore-forming agent and provide a consolidated, sintered tube of calcium-doped LaMnO₃ having a density of from 60% to 85% of theoretical density and a Coefficient of Thermal Expansion of from 10.2 X 10⁻⁶°C to 10.8 X 10⁻⁶°C.