a lithium ion battery is disclosed in which the negative electrode material comprises carbon nanostructures having no dimension greater than 2 μm . the battery has a high reversible capacity of the order of 400 mah / g to 500 mah / g which can be maintained over a long cycle - life . the carbon nanostructures may be mixed with graphite to improve conductivity . the carbon nanostructues may be synthesized using an afi template material followed by calcination .