Electrode design

Fig. 11. Types of (a) collecting plate and (b) discharge electrode designs.

These multidimensional analyses do not necessarily predict overall generator performance or operating characteristics significantly more accurately than do the qua si-one-dimensional analyses, which are more economical to mn. Thus the latter are used for general channel design calculations, and the more sophisticated codes mainly to deal with more detailed aspects of channel operation. For example, current concentrations at electrode edges can be predicted by use of the more sophisticated codes. This allows appropriate electrode design for the condition. 

Conductive-Induction Machines Electrostatic separators exploiting the principle of conductive induction will generally use the follovv -ing electrode designs ... 

The Sony cell is rapidly outstripping all other batteries for such uses as laptop computers, especially since the electrode design has overcome danger of fire which held back earlier versions of the battery. It has an energy density of >200 watt-... 

The focused current system employs the guarded electrode design shown in Figure 4-274. 

The electrodes designed for permanent installation on deep-water structures must be protected from damage but must also correctly view the protected structure. Thus electrodes must be closely placed to the structure to avoid the incorporation of an IR element in the potential measured, but must not create a protection shadow which could cause a false indication of the protection level. 

But all these are problems which can be overcome by appropriate catalyst-electrode design and by appropriate choice of the solid electrolyte and thus of the promoting species. 

Aqueous, alkaline fuel cells, as used by NASA for supplemental power in spacecraft, are intolerant to C02 in the oxidant. The strongly alkaline electrolyte acts as an efficient scrubber for any C02, even down to the ppm level, but the resultant carbonate alters the performance unacceptably. This behavior was recognized as early as the mid 1960 s as a way to control space cabin C02 levels and recover and recycle the chemically bound oxygen. While these devices had been built and operated at bench scale before 1970, the first comprehensive analysis of their electrochemistry was put forth in a series of papers in 1974 [27]. The system comprises a bipolar array of fuel cells through whose cathode chamber COz-containing air is passed. The electrolyte, aqueous Cs2C03, is immobilized in a thin (0.25 0.75 mm) membrane. The electrodes are nickel-based fuel cell electrodes, designed to be hydrophobic with PTFE. 

Good accuracy and precision were obtained in connection to 100 pL blood samples. A wide range of amperometric enzyme electrodes, differing in the electrode design or material, membrane composition, or immobilization approach have since been described. 

Porous flow-through electrode design (coulometric or amperometric). 

The porous hydrophobic film of previous electrode designs has now been substituted with a new layer based on a mixture of particles of hydrophobic carbon and PTFE binder. This mixture is very similar in composition to the catalytic layer. This particular modification provides several advantages ... 

Fig. 18.5 Specialised BiChlor mesh electrode design incorporating spider current distributors.

Another feature that minimises resistance is the choice of electrode mesh. ICI ETB carried out extensive trials of different electrode designs including different types of mesh. The designs were computer-modelled and tested to find the optimum combi-... 

The American partners in this large effort95 have reported, separately, on the novel electrode designs for administering this electrochemotherapy electrical pulses permeabilize, or... 

Armaou and Christofides (1999) present a two-electrode design for the deposition of 500-A films on an 8-cm wafer, which sits on top of the lower electrode, as shown in Fig. 10.4-2. The reactor is fed with 10% SiEE (silane) in He at 1 torr through a showerhead. An RF power source, at 13.56 MHz frequency, is used to generate the plasma, which is transported by convection and diffusion to the surface of the wafer where reaction occurs to deposit amorphous silicon. Electrical heating elements are positioned below the wafer and along the walls to achieve a uniform temperature of the plasma and wafer at 500 K. 

Figure 4.11 A solid-state electrode showing a first-order response. An electrode designed to measure the activity of silver ions uses a crystalline membrane of silver sulphide. An equilibrium between the mobile silver ions of the membrane and the silver ions in the solutions results in the development of a potential difference across the membrane.

A CV voltammogram can be recorded under either a dynamic or a steady state depending on the electrode design and solution convection mode. In a stationary solution with a conventional disk electrode, if the scan rate is sufficiently high to ensure a non-steady state, the current will respond differently to the forward and backward potential scan. Figure 63 shows a typical CV for a reversible reduction.1... 

The primary focus of ongoing research is to improve the performance of the cell and lower its cost. The principal areas of development are improving cell membranes, handling the CO in the fuel stream, and refining electrode design. There has been an effort to incorporate system requirements into the fuel cell stack in order to simplify the overall system. This work has included a move toward operation with zero humidification at ambient pressure and direct fuel use. 

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