Sintering large area ceramic films

A process for making a sintered lithium-stuffed garnet thin film, wherein the method comprises:

• (a) providing a green film comprising lithium-stuffed garnet powder and a binder;
• (b) providing a first setter and a second setter, wherein the first setter and second setter each comprise at least 5 atomic % lithium (Li) per setter;
• (c) placing the green film between and in contact with the first setter and the second setter;
• (d) losing contact between the green film and the second setter, wherein the second setter is within 2 cm of the green film but not in contact with the green film;
• and
• (e) heating the green film to at least 900° C.

An apparatus comprising

• a bottom setter;
• a top setter;
• and
• a green film between the bottom setter and the top setter;
• wherein the green film contacts the bottom setter but does not contact the top setter.