Method of making a textured electrolyte sheet for a fuel cell device

A method of making a sintered electrolyte sheet, said method comprising the steps of:

• (a) providing a green slip on a patterned polymer carrier with at least 0.5 micrometer surface variations, said slip containing a volatile material, said volatile material comprising:
• (i) at least one binder, or at least one binder precursor capable of forming a binder;
• and
• (ii) at least one plasticizer;
• such that the ratio of binder to plasticizer by weight is 1 to 3.5;
• (b) spreading said slip on said patterned polymer carrier to form a corresponding textured surface on green electrolyte sheet, thereby forming textured green electrolyte sheet having at least one textured surface, said textured green electrolyte sheet having an average thickness of less than 100 microns;
• (c) at least partially evaporating said material from the said textured green electrolyte sheet;
• (d) sintering the textured green electrolyte sheet to provide a sintered electrolyte sheet with substantially non-porous body, the non porous body having a textured surface with multiple indentations therein, wherein the thickest part of the sintered electrolyte sheet is at least 0.5 micrometers greater than the thinnest part of the sintered electrolyte sheet and the average thickness of said electrolyte sheet is less than 100 microns.

A method of making an electrolyte sheet, said method comprising the steps of:

• (a) providing a green slip on a patterned polymer carrier, said slip containing a volatile material, said volatile material comprising:
• (i) at least one binder, or at least one binder precursor capable of forming a binder;
• and
• (ii) at least one plasticizer;
• such that the ratio of binder to plasticizer by weight is 1 to 3.5;
• (b) spreading said slip on said patterned polymer carrier to form a green electrolyte sheet having thickness variations and an average thickness of less than 100 microns;
• (c) at least partially evaporating said material;
• (d) sintering the green electrolyte sheet to provide an electrolyte sheet with (i) substantially non-porous body and the average thickness of is less than 100 microns and (ii) indentations or grooves such that the thickest part of the electrolyte sheet is 0.5 to 6 micrometers greater than the thinnest part of the electrolyte sheet and the indentations or grooves have depth to width ratio between 1:1 and 6:1.