A life-cycle energy analysis of single wall carbon nanotubes produced through laser vaporization

Due to their unique electrical, thermal, and mechanical properties, single wall carbon nanotubes (SWCNTs) have attracted considerable interest for use in a number of applications such as lithium ion batteries, fuel cells, and conductive wiring. However, the energy required to synthesize and purify SWCNTs in the manufacturing phase must be considered in order to fully realize the benefits in the use phase, and gain a life-cycle understanding. The laser vaporization process consists of production of the raw SWCNT material, refluxing in acid to reduce metal content, and a final burn to remove amorphous carbon content. Each step introduces electrical and material inputs that can be adjusted to affect the yield and material properties. Various manufacturing techniques exist for SWCNTs and each results in materials of differing purity (mass fraction of SWCNTs), chirality, diameter, and length distributions. While manufacturing energies for some of these other SWCNT production techniques have been reported, a systematic analysis of the laser vaporization processes energy consumption from each step is lacking, and can be used to address and reduce the areas of greatest energy use.