A feasibility study of scaling-up the electrolytic production of carbon nanotubes in molten salts

The feasibility of scaling-up the electrolytic production of carbon nanotubes in molten salts has been investigated with the aid of electron microscopy (TEM and SEM). Using molten LiCl as the electrolyte and commercial graphite as both cathode and anode materials, carbon nanomaterials, including nanotubes, were prepared by constant voltage electrolysis. The cell was more than 20 times as large as that used in previous work. The nanotube concentration in the final product increased with cell voltage (including iR drop) from 1 vol.% at 4.0 V to 35 vol.% at 8.4 V. Under desired conditions, the charge and energy consumption for the cathode erosion was 0.28 Ah/g and 4.1 Wh/g, of which 60-70 wt.% were for producing nanomaterials (nanotubes: > 30 vol.%). When adding 1 wt.% SnCl2 to the electrolyte, partial and fully filled nanotubes were obtained with the nanomaterials containing up to 20 wt.% Sri. Preliminary results from applying the product as the electrode in lithium ion batteries are reported. (C) 2002 Elsevier Science Ltd. All rights reserved.