Double-Walled carbon nanotubes (CNTs) can be used in various fields including additives in polymers, catalysts, electron field emitters for cathode ray lighting elements, flat panel display, gas-discharge tubes in telecom networks, electromagnetic-wave absorption and shielding, energy conversion, lithium-battery anodes, hydrogen storage, nanotube composites (by filling or coating); Nanoprobes for STM, AFM, and EFM tips, nanolithography, nanoelectrodes, drug delivery sensors, reinforcements in composites, supercapacitor.