US Patent 7189476 - Rechargeable batteries using metal encapsulating nanotubes

http://www.freepatentsonline.com/7189476.pdf

Conventional rechargeable lithium cells have problems related to dendrite growth on the anodes during cycling. This patent proposes metal encapsulating carbon nanotubes as a material to achieve improved capacity and reversibility. Claim 1 reads:

1. A rechargeable lithium cell incorporating an anode, a reversible cathode, and an electrolyte, said anode comprising carbon nanotubes, characterized in that the nanotubes contain within them a metal or a metalloid selected from the group consisting of aluminum, tin, metallic alloys containing aluminum or tin, or silicon, that can form alloys reversibly with lithium over a range of compositions wherein the metal or metalloid is inside said nanotubes.