NOVELTY - Powder comprises carbon nanostructures, at least a portion of the carbon nanostructures defining an internal cavity containing metallic lithium, a lithium compound, or an alloy between lithium and at least one other metal or metalloid.    USE - The powder is useful: as a component part of an anode for a lithium-ion rechargeable cell (claimed); and in electrode for lithium ion cells e.g. lithium-ion polymer cells.    ADVANTAGE - The powder exhibits improved mobility, modifying flow and agglomeration properties, electrical storage capacity, longer cell lifetime and density and reduces the charging capacity of the cell.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for:    (1) forming the powder comprising either (a) arranging a graphite electrode in contact with a molten salt in an electrolysis cell, where the molten salt comprises lithium, lithium salt, a salt of the other metal or metalloid, and a non-chloride silicon salt, (b) applying a cathodic potential to the graphite electrode such that metallic lithium reacts at the graphite electrode, silicon deposits at the graphite electrode and the graphite electrode disintegrates into the carbon nanostructures containing lithium, (c) collecting the nanostructures, and (d) removing salt from the nanostructures without removing lithium, or the step (a) as above per se, applying the cathodic potential to the graphite electrode such that the other metal or metalloid deposits at the graphite electrode and lithium reacts with the graphite electrode such that it disintegrates into the carbon nanostructures containing an alloy of lithium and the other metal or metalloid, and the steps (c) and (d) as above per se;    (2) forming an anode for a lithium-ion cell comprising coupling a powder to an electrical conductor, where the powder is formed by the method;    (3) the anode for the lithium-ion rechargeable cell comprising the powder produced by method coupled to the conductor; and    (4) a lithium-ion rechargeable cell comprising the anode or the anode formed using the method.