Material and energy intensity of fullerene production.

Fullerenes are increasingly being used in medical, environmental, and electronic applications due to their unique structural and electronic properties. However, the energy and environmental impacts associated with their commercial-scale production have not yet been fully investigated. In this work, the life cycle embodied energy of C(60) and C(70) fullerenes has been quantified from cradle-to-gate, including the relative contributions from synthesis, separation, purification, and functionalization processes, representing a more comprehensive scope than used in previous fullerene life cycle studies.

Enhanced capacity and rate capability of carbon nanotube based anodes with titanium contacts for lithium ion batteries.

Carbon nanotubes are being considered for adoption in lithium ion batteries as both a current collector support for high-capacity active materials (replacing traditional metal foils) and as free-standing electrodes where they simultaneously store lithium ions. The necessity to establish good electrical contact to these novel electrode designs is critical for success. In this work, application of nickel and titanium as both separable and thin film electrical contacts to free-standing single-wall carbon nanotube (SWCNT) electrodes is shown to dramatically enhance both the reversible lithium ion capacity and rate capability in comparison with stainless steel.

Multi-walled carbon nanotube paper anodes for lithium ion batteries.

The lithium ion capacity has been measured for multi-walled carbon nanotubes (MWCNTs) synthesized by injection chemical vapor deposition (CVD) using a cyclopentadienyl iron dicarbonyl dimer catalyst. The high quality of the as-synthesized MWCNTs has enabled free-standing electrodes to be fabricated independent of polymeric binder or copper support. Galvanostatic cycling of these electrodes demonstrates excellent reversibility and coulombic efficiency (> 97% after cycle 3) using propylene carbonate based electrolytes, with no evidence for material degradation.

Effects of carrier gas dynamics on single wall carbon nanotube chiral distributions during laser vaporization synthesis.

We report on the utility of modifying the carrier gas dynamics during laser vaporization synthesis to alter the single wall carbon nanotube (SWNT) chiral distribution. SWNTs produced from an Alexandrite laser using conventional Ni/Co catalysts demonstrate marked differences in chiral distributions due to effects of helium gas and reactor chamber pressure, in comparison to conventional subambient pressures and argon gas. Optical absorption and Raman spectroscopies confirm that the SWNT diameter distribution decreases under higher pressure and with helium gas as opposed to argon.

Purity assessment of single-wall carbon nanotubes, using optical absorption spectroscopy.

A demand currently exists for a method of assessing the purity of single-wall carbon nanotubes (SWNTs), which will allow for meaningful material comparisons. An established metric and protocol will enable accurate and reproducible purity claims to be substantiated. In the present work, the ability to accurately quantify the mass fraction of SWNTs in the carbonaceous portion of a given sample is demonstrated, using optical absorption spectroscopy on both laser and arc discharge-generated SWNT-N,N-dimethylacetamide (DMA) dispersions.