Pore electrodes

Amatniek, E., 1958, Measurement of bioelectric potentials with microelectrodes and neutralized input capacity amplifiers, Trans. IRE., PGME 10 3-14. 

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Curtis, D. R., 1964, Microelectrophoresis, in Physical Techniques in Biological Research, Vol. 5 (W. L. Nastuk, ed.). Academic Press, New York. 

DeFelice, L. F. and Firth, D. R., 1971, Spontaneous voltage fluctuations in glass micro-electrodes, Trans. IEEE, 18 339-351. 

Ferris, C. D., 1971, Electrode artifact in microelectrode systems, Proc. 8th Ann. RMBS, Ft. Collins, Colorado, pp. 27-32. 

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Current and Potential Distribution in a Conical Pore Electrode.394... 

Weidner JW, Fedkiw PS (1991) Effect of Ohmic, mass-transfer, and kinetic resistances on linear-sweep voltammetry in a cylindrical-pore electrode. J Electrochem Soc 138 2514-2526... 

Zhao, H., Li, L., Fan, H. J. et al. 2012. Exocytosis of SH-SY5Y single cell with different shapes cultured on ITO micro-pore electrode. Mol. Cell. Biochem. 363 309-313. 

Impedance plots - Fig. 19.4 shows experimental impedance plots (complex plane representation) obtained for both the as-deposited and the honeycomb diamond electrodes at 0.4 V. The plots for the pore types, 60 x 500 nm (Fig. 19.4c), 70 x 750 nm (not shown), and 400 nm x 3 mm (Fig. 19.4d), exhibit two distinct domains a high frequency domain, where the impedance behavior is that expected for a cylindrical pore electrode, with a characteristic linear portion at a 45° angle, and a low frequency domain, where the behavior is... 

The plant incorporating the air cathode electrolyzer must include a high performance air scmbbing system to eliminate carbon dioxide from the air. Failure to remove CO2 adequately results in the precipitation of sodium carbonate in the pores of the cathode this, in turn, affects the transport of oxygen and hydroxide within the electrode. Left unchecked, the accumulation of sodium carbonate will cause premature failure of the cathodes. 

Ion Removal and Metal Oxide Electrodes. The ethylenediamine ( )-functional silane, shown in Table 3 (No. 5), has been studied extensively as a sdylating agent on siUca gel to preconcentrate polyvalent anions and cations from dilute aqueous solutions (26,27). Numerous other chelate-functional silanes have been immobilized on siUca gel, controUed-pore glass, and fiber glass for removal of metal ions from solution (28,29). 

The other type of nickel electrode involves constmctions in which the active material is deposited in situ. This includes the sintered-type electrode in which nickel hydroxide is chemically or electrochemically deposited in the pores of a 80—90% porous sintered nickel substrate that may also contain a reinforcing grid. 

Eor the negative electrolyte, cadmium nitrate solution (density 1.8 g/mL) is used in the procedure described above. Because a small (3 —4 g/L) amount of free nitric acid is desirable in the impregnation solution, the addition of a corrosion inhibitor prevents excessive contamination of the solution with nickel from the sintered mass (see Corrosion and corrosion inhibitorsCorrosion and corrosion control). In most appHcations for sintered nickel electrodes the optimum positive electrode performance is achieved when one-third to one-half of the pore volume is filled with active material. The negative electrode optimum has one-half of its pore volume filled with active material. 

Considerable increases in the capacity density of the electrodes have been achieved through the use of high-density / -Ni(OH)2 with a uniform particle size, a narrow range of pore sizes, and a high tapping density (1.9-2.0gem"3) [15, 16]. 

In the older battery literature the term separator is frequently used very loosely, to include all nonmetallic solid components between the electrodes, such as supporting structures for active materials (tubes, gauntlets, glass mats), spacers, and separators in a narrow sense. In this section, only the last of these, the indispensable separating components in secondary cells, will be termed separators , distinguished from the others by their microscopically small pores, i.e., with a mean diameter significantly below 0.1 mm. 

Pores generally are not of a hose-like configuration of constant diameter, in a straight-line direction from one electrode to the other. In practice, separators pores are formed as void between fibers (Fig. 1),... 

Typical pore size distributions result in mean pore diameters of around 15 //m. Even long and intensive efforts did not succeed in decreasing this value decisively in order to enable production of micropo-rous pocketing material resistant to penetration [65, 66], In practice PVC separators prove themselves in starter batteries in climatically warmer areas, where the battery life is however noticeably reduced because of increased corrosion rates at elevated temperature and vibration due to the road condition. The failure modes are similar for all leaf separator versions shedding of positive active mass fills the mud room at the bottom of the container and leads to bottom shorts there, unless — which is the normal case — the grids of the positive electrodes are totally corroded beforehand. 

The prime requirements for the separators in alkaline storage batteries are on the one hand to maintain durably the distance between the electrodes, and on the other to permit the ionic current flow in as unhindered a manner as possible. Since the electrolyte participates only indirectly in the electrochemical reactions, and serves mainly as ion-transport medium, no excess of electrolyte is required, i.e., the electrodes can be spaced closely together in order not to suffer unnecessary power loss through additional electrolyte resistance. The separator is generally flat, without ribs. It has to be sufficiently absorbent and it also has to retain the electrolyte by capillary forces. The porosity should be at a maximum to keep the electrical resistance low (see Sec. 9.1.2.3) the pore size is governed by the risk of electronic shorts. For systems where the electrode substance... 

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