Xenu's Battery in "Knight and Day"?

In James Mangold's action comedy,"Knight and Day", Tom Cruise plays Roy Miller, a government-trained killer. Roy has stolen the prototype of a battery so awesome that it can power a good-sized city indefinitely.

Now this sounds familiar. Where have I heard read/heard about a battery that would last forever. or an eternal battery?

Why L.Ron Hubbard's secret scripture from Scientology. The story of Xenu is covered in OT III, part of Scientology's secret "Advanced Technology" doctrines taught only to advanced members.

[Xenu] is now locked away in a mountain on one of the planets and kept in by a force-field powered by an eternal battery.

Uh-oh, Tom, you haven't been leaking Scientology secrets, just for a plot line, have you?

"I'm Not From This Planet" L.Ron Hubbard Remix
Hear about the eternal battery in L.Ron's story of Xenu [starts about 0:45] (in his own voice, naturally).