You can make your own lithium-ion batteries if you have a source ... [Bill Porter] put together a quick tutorial where he makes a 14.4V 2.2 AH battery for about $10. He picked up a set of cable ...
The UniPal Plus is a universal battery charger which claims to be capable of charging "practically all" 3.6/3.7 or 7.2/7.4v Lithium-Ion batteries and can charge over 300 different camera batteries.