Yes, Its True, With Sony’s New PSP Battery you can Play Games for 11 Hours, Recently Sony Japan has announced their PSP battery pack which has 2200mAH which is a K more from the standard 1200mAH. Unforchunatly This new fat battery will be compatible only with the new PSP-2000 only.
You can get it in Japan from 19th of March for ¥5500 ($50USD).