You're right on all those accounts (5.5v, 0.22F). They are the same as the PRAM caps in many Macintosh iBooks. And the suckers leak like Amiga NiCds! If you iBook suddenly stopped turning on or turns on intermittently, this could be the reason!
I've found them for your price (around $2-3) at Jameco which is local to me. I might have an extra one. I'll look to see if I still have it and if you don't find any, let me know. Shipping in an envelope should do it. I also have some crystals in case you're looking for any. Let me know.
Edit: Doh! yes, of course they're caps. Not batteries. Tired...
