Thursday, March 20, 2008
Bamboo-like Carbon Nanotubes in Lithium Ion Batteries
The test cell with B-CNTs as anode material shows low reversible capacity of 135 mAh g^(-1) and very low initial cycle efficiency of 17.3%, which indicates that so-prepared B-CNTs is not suitable for anode material in lithium ion batteries. However, the EIS spectra prove that B-CNTs is better electric conductive additive than MWCNTs and traditional carbon black (CB). The electric resistance of the electrode is decreased around 20 Ohm when B-CNTs is used instead of CB. The cycle stability is also enhanced, thus B-CNTs is promising electric conductive additive in electrode for lithium ion batteries.
Source: Journal of Power Sources (2008), article in press.
Manganese oxide/carbon nanotube composite for rechargeable lithium battery cathode
Source: Materials Letters (2008), article in press.
Highly stable SWCNT/DNA hybrids
Researchers have removed the unwrapped double-stranded DNA (dsDNA) from the dsDNA-solubilized single-wall carbon nanotube (SWCNT) aqueous solutions to obtain size-separated DNA/SWCNT hybrids (fr1-fr4). By using the re-injection procedure of the size-exclusion chromatography SEC-HPLC, researchers have discovered that, at the SEC chromatograph level, the fractionated dsDNA/SWCNT hybrids are highly stable without desorption from the hybrids to the unbound dsDNA for at least one month. The interaction of single-strand DNA (ssDNA) and SWCNTs is expected to be stronger than that of dsDNA and SWCNTs. Therefore, isolated ssDNA/SWCNTs hybrids should have similar stability. The present finding is important not only in the fundamental analysis of dsDNA/SWCNT hybrids, but also for their applications especially in biological areas.
Source: Chemical Physics Letters (2008), article in press
Binding nanoparticles covalently onto carbon nanotubes
The strategy employed is quite generic and applicable to a variety of nanoparticles. More work is under way to extend this method to attach other nanoparticles (e.g. semiconductor nanoparticles, electrical nanoparticles, bio-nanoparticles, etc.) on the CNTs by choosing different kinds of surface functional groups and surface charges. Therefore, the covalent binding process can be regarded as a general approach to effective functionalization of carbon nanotubes with various nanoparticles for a wide range of potential applications, including in advanced sensing, nanoelectronics, chemical sensing, field-emission displays, nanotribology, cell adhesion/biorecognition investigations, and catalytic systems.
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