CARBON NANOTUBULE MEMBRANES FOR ELECTROCHEMICAL ENERGY-STORAGE AND PRODUCTION

Ensembles of aligned and monodisperse tubules of graphitic carbon can be prepared by a templating method(1-4) that involves the chemical-vap our deposition of carbon within the pores of alumina membranes(5-7). T ubules with diameters as small as 20 nm have been prepared in this way (7,8). The carbon comprising these tubules can be transformed from a d isordered material to very highly ordered graphite(5). Here we show th at template-synthesized carbon tubules can be fabricated as free-stand ing nanoporous carbon membranes, and that narrower, highly ordered gra phitic carbon nanotubes can be prepared within the membrane's tubules. Both the outer and the inner tubules are electrochemically active for intercalation of lithium ions, suggesting possible applications in li thium-ion batteries(9,10). The membranes can also be filled with nanop articles of electrocatalytic metals and alloys. Such catalyst-loaded m embranes can be used to electrocatalyse O-2 reduction and methanol oxi dation, two reactions of importance to fuel-cell technology.