Alt-BEAM Archive
Message #05205
To: "'beam@sgiblab.sgi.com'" beam@sgiblab.sgi.com
From: Wilf Rigter Wilf.Rigter@powertech.bc.ca
Date: Fri, 9 Jul 1999 13:04:18 -0700
Subject: [alt-beam] Re: Ultracapacitors
Tinkering with nonlinear systems >>> butterfly effect. For those who have
not heard of it before, the "butterfly effect" was accidentally discovered
(by whom?) and is used as an extreme example of the non-linear behaviour of
weather dynamics. It suggests that the effect of a butterfly flapping it's
wings in Japan could result in a tornado in the US midwest (just in case
you' were looking for someone to blame;) Discovering that we are surrounded
by chaotic systems led to a paradigm shift in our understanding of the
universe and is at least part of the reason that MarkT. is searching for
chaotic solutions for biomorphic systems.
enjoy
Wilf Rigter mailto:wilf.rigter@powertech.bc.ca
tel: (604)590-7493
fax: (604)590-3411
> -----Original Message-----
> From: John A. deVries II [SMTP:zozzles@lanl.gov]
> Sent: Friday, July 09, 1999 8:59 AM
> To: beam@sgiblab.sgi.com
> Subject: Ultracapacitors
>
> From the July 1999 "Reflections", a monthly publication of the Los Alamos
> National Laboratory
>
> Serendipitous discovery: From unexpected impurity to vital additive (by
> Todd Hanson)
>
> Over the past few years, the starting materials, or monomers, provided by
> John Ferrari's team at the University of Texas in Dallas for making
> conducting polymer active materials for ultracapacitors have been of the
> highest quality. The team's expertise in organic chemistry provided the
> foundation for the development of the ultracapacitor, yet it was an
> impurity in one batch of monomers that led to a breakthrough in
> ultracapacitor research.
>
> Last summer, Steven Shi of Electronic and Electrochemical Materials and
> Devices (MST-11) was fabricating an ultracapacitor using conducting
> polymer
> as the electrode active material. The polymer was electropolymerized from
> its monomer solution onto a carbon paper disk bonded to a current
> collector.
>
> Shi had used up one batch of the monomer and was starting with a fresh
> batch -- subsequently named the "April batch" - when the disk displayed a
> rusty red color rather than the usual black. Instead of discarding the
> material and starting over, Shi decided to investigate.
>
> He found that the rust-colored disk was significantly superior to the
> original black in terms of polymer morphology and material stability. The
> red material had a highly porous, open structure, with polymer grain size
> in the sub-micron range, while the black material showed a relatively
> compact structure with a polymer grain size in he range of several
> microns.
>
> The new morphology provided a large, effective, electrolyte-accessible
> polymer surface area, leading to fast charge/discharge dynamics. More
> surprisingly, the red material also helped extend the device cycle life in
> pulsed discharge mode from 100,000 cycles to 2.7 million cycles.
>
> Shi brought this discovery to the attention of principal investigator
> Shimson Gottesfel, also of MST-11, who suggested that Shi test subsequent
> batches. Using new batches of the monomer, the electrodeposited polymer
> returned to its ordinary black color, and the cycle life of the
> ultracapacitor dropped back to 100,000 cycles. It was clear that the
> April
> batch was an anomaly.
>
> Gottesfeld suggested that Ferraris re-analyze the April batch, and the
> Texas team confirmed that it contained a previously undiscovered
> component.
> The impurity had been hidden during the initial analysis beneath a large
> spike in the gas chromatography spectrum -- an analytical method used to
> determine the chemical components of complex mixtures. It was easy to
> miss.
>
> Using information gained from the analysis, Shi added the component to a
> solution of the pure monomer and electropolymerized the active material
> from that mixed solution. The resulting polymer showed the same superior
> properties as the April batch. Somehow, the impurity had improved the
> quality of the conducting polymer. The unexpected component has since
> been
> promoted from an impurity to a vital additive.
>
> Uncertain as to exactly what makes the new conduction polymer more robust
> -- either the second component strengthens the conducting polymer's
> bonding
> to the carbon or provides cross-linking in the polymer -- the Los Alamos
> researchers continue to investigate, aiming at further improvements in
> ultracapacitor technology.
>
>
> (copyright 1999 DOE/UC, yaddita, yaddita, yaddita)
>
> p.s. hey - YOU try typing "electropolymerized" a few times and see what
> happens to YOUR fingers!
>
>
> ---------------------------------------------------------------
> John A. deVries II
> zozzles@lanl.gov
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