Graphite fiber electrodes

Knecht, L.A. Guthrie, E.J. Jorgenson, J.W. On-column electrochemical detector with a single graphite fiber electrode for open-tubular liquid chromatography. Anal. Chem. 1984, 56, 479 82. 

The proper way to do such experiments is to introduce the compound by iontophoresis, and a series of excellent studies by Armstrong-James, Millar, and Kruk has illustrated this (Armstrong-James et aL, 1980a Kruk et aL, 1980 Millar et aL, 1981). These studies precisely quantify amounts of iontophoresed NE, DA, and 5-HT by electrochemical detection at graphite-fiber electrodes in an adjacent multibarrel pipette arrangement. These studies were carried out by linear sweep voltammetry using very high potential sweep rates (ca. 100 V/sec). 

The electroreduction of oxygen in alkali occurs readily at carbon electrodes. Currently used electrodes are a graphite fiber trickle-bed/perforated bipole reactor, operated at U.B.C (University of British Columbia) [210,211] a com-... 

Carbon fiber or graphite fiber materials, available, for example, as felt, clothes, or paper, and so on, are state of the art for realizing conductive diffusion zones in fuel cells but also they can be used as electrodes. They attain a very high porosity (free space volume up to 80%) and a surprisingly good elasticity. 

In order to extend the effective electrode area in principle three-dimensional electrodes are possible, for example, by using a packed particle bed, a sintered or foamed metal, or a graphite fiber felt. But the depth of the working electrode volume usually is only small (it is dependent on the ratio of the electrode and electrolyte conductivity, for example, [45]). 

Crasto, A.S., Own, S.H. and Subramanian, R.V. (1988). The influence of the interphase on composite properties Poly(cthylene-co-acrylic acid) and poly(methyl vinyl ether-co-maleic anhydride) electrode-posited on graphite fibers. Polym. Composites 9, 78-92. 

The optical anisotropy observed in most carbon materials reflects the ordered stacking of graphite-like microcrystalline units that has been recognized to be essential in determining their properties. Pitch-based carbon fiber, electrode and metallurgical cokes, and carbons for nuclear reactors are characterized by their anisotropic texture since this structural factor is fundamentally related to their mechanical, thermal, electronic, and chemical properties (1-5) ... 

Carbon fiber electrode - Edison produced the first carbon fibers by carbonization of cotton threads in 1879. Today polyacrylonitrile (as well as Rayon and various other organic precursors) is the most common precursor for carbon fiber formation [i]. Carbonization of polyacrylonitrile is carried out at 1500 °C to give highly electrically conducting fibers with 5-10 pm diameter. Fibers carbonized at up to 2500 °C are more graphitic with a carbon content of >99%. Carbon fiber-based materials have found many applications due to their exceptionally high tensile strength. In electrochemistry carbon fiber -> micro electrodes are very important in analytical detection [ii] and for in vivo electrochemical studies [iii]. Carbon fiber textiles are employed in - carbon felt electrodes. 

Whenever a new material is discovered, the focus quickly shifts from fundamental research to the more applied aspects. Fullerenes and carbon nanotubes are no different in that respect. In the case of fullerenes thousands of new materials are synthesized, but a market-suitable product is not yet available. Perhaps the carbon nanotubes are closer to applications. Graphite fibers have proven to be very useful and nanotubes are at the very least, an extreme in the spectrum of the graphite fiber size scale. They retain many of the favorable properties of graphite and add to them new properties related to their nanoscopic size, as pointed out above. Directions that appear to have some promise involve different properties. Nanotube lamps and displays are already looming on the horizon. Also, nanotube films may be used as electrodes in solid state heterostructures [182]. 

Yamaguchi, K., Suzuki, J., Saito, M., Sekine, K., and Takamura, T., Stable charge/discharge of Li at a graphitized carbon fiber electrode in a pure PC electrolyte and the initial charging loss, J. Power Sources, 91, 159, 2001. 

Electrode materials Pt. platinum PG. pyrographite AC, active carbon GC. glasslike carbon CF. carbon fiber. CCEs, ceramic carbon electrodes CPE. carbon (graphite) paste electrode Soim e-. Refs. 12, 201. and 206-221... 

Sathe N, Botte GG (2006) Assessment of coal and graphite electrolysis on carbon fiber electrodes. J Power Sources 161 513-523... 

Fig. 25. Single graphite fiber EC detector orKnechtei ai (1984). (A)Cell inlet, (B) capillary column, (C) graphite fiber inserted into capillary, (D) epoxy, (E) wo ng electrode sheath (glass tube), (F) mercury electrical contact, (G) O ring, (H) outer cell body (glass tubeX and (I) Ag/AgCI tefeience/auxiliary eketrode.

G R Stafford, G L Cahen and G E Stoner, Graphite fiber-polymer matrix composites as electrolysis electrodes , J Electrochem Soc 1991 138(2) 425-430. 

Highly oriented carbon fibers ( graphite fibers ) are a very convenient starting material for preparation of microelectrodes, namely because of their mechanical stability, high electronic conductivity and good biological compatibility. Preparation of encapsulated microdisc electrodes with diameter up to 1 /xm will be discussed. 

Figure 7.10 Capacitance of PPy/graphite fiber composite electrode in 1 M KCl at a 10 mV/s sweep rate. Reprinted with permission from Ref. 200. Copyright 2002 Elsevier Science B.V.

Park J. H., Ko J. M., Parka 0. 0., and Kim D. W., Capacitance properties of graphite/polypyrrole composite electrode prepared by chemical polymerization of pyrrole on graphite fiber, J. Power Sources, 2002, 105,20-25. 

The well-known fact that the rate of electrochemical reactions is proportional to the surface area of the electrode makes ICP electrospun fibers ideal candidates as electrode materials in other small electrochemical devices such as supercapacitors and batteries. The small diameter of the fibers makes it possible for ions to rapidly diffuse between the center of the fiber and the surrounding electrolyte, which should lead to enhanced performance of electrochemical devices constructed from these electrospun fibers. Although no energy storage devices have so far been fabricated that utilize ICP electrospun fiber electrodes, there have been reports of using graphitized polyacrylonitrile electrospun fibers as the electrode material for fabricating carbon-based supercapacitors [186]. 

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