Conductive particles

Instead of electrically conductive additives, thermally conductive additives have also been used to construct thermally conductive tapes used for heat management [ 132]. A particular example of an electrical conductive tape is a z-axis conductive construction shown in Fig. 17. In this case, the conductive particles make contact in the z-direction of the tape without doing so with neighboring particles in the... 

A lithium anode mixed with conductive particles of Cu or Ni was studied by Saito et al. they obtained an improvement in the cycling efficiency (Fig.6) [80]. Their idea is based on the recombination of dead lithium and formation of many active sites for deposition. 

The main notion of the percolation theory is the so-called percolation threshold Cp — minimal concentration of conducting particles C at which a continuous conducting chain of macroscopic length appears in the system. To determine this magnitude the Monte-Carlo method or the calculation of expansion coefficients of Cp by powers of C is used for different lattices in the knots of which the conducting par-... 

The equipment is branded as the AQA total and uses a special three-dimensional electrode to produce specific current-voltage impulses to the electrically conductive particles, resulting in a local displacement of the hardness-carbon dioxide equilibrium. 

During the last year a bipolar particular cell has been described (Fleischmann et al., 1971d). The cell shown in Fig. 18 consists of a packed bed of mixed conducting and non-conducting particles a d.c. potential is applied between two feeder electrodes situated at the ends... 

Fig. 18. Bipolar particulate cell. conducting particles, o non-conducting glass beads.

The concept of a fluidized bed consisting of electrically conducting particles as a statistically continuous electrode was first discussed by Le Goff et al. (Lie). Interesting similarities with heat-transfer studies in fluidized beds may be exploited to advantage by use of the limiting current method. 

The conductive particles in the volume of electrode make a so-called chain structures. As it is seen from the model, the electrical circuit assumes interconnection of the active mass particles in the solid phase of the electrode, while the external collector consists of a long chain of resistors. 

In accordance with this model, the current path is made through the contact resistance external collector - volume collectors (Rki), then goes through many other resistances, such as bulk resistance of the conductive particles (Rvi) and the contact resistance between the conductive particles in the volume of the electrode (Rci) at the end, there is contact resistance between the conductive particles and active mass particles (Rmi). 

Figure 2. Charging of a conducting particle with diameter D making contact with a conducting wall in the presence of an electric field E.

The model is most vulnerable in the way it accounts for the number of particles that collide with the electrode [50, 115], In the model, the mass transfer of particles to the cathode is considered to be proportional to the mass transfer of ions. This greatly oversimplifies the behavior of particles in the vicinity of an interface. Another difficulty with the model stems from the reduction of the surface-bound ions. Since charge transfer cannot take place across the non-conducting particle-electrolyte interface, reduction is only possible if the ion resides in the inner Helmholtz layer [116]. Therefore, the assumption that a certain fraction of the adsorbed ions has to be reduced, implies that metal has grown around the particle to cover an identical fraction of the surface. Especially for large particles, it is difficult to see how such a particle, embedded over a substantial fraction of its diameter, could return to the plating bath. Moreover, the parameter itr, that determines the position of the codeposition maximum, is an artificial concept. This does not imply that the bend in the polarisation curve that marks the position of itr is illusionary. As will be seen later on, in the case of copper, the bend coincides with the point of zero-charge of the electrode. 

The Coulter method of sizing and counting is based on measurable changes in electrical resistance produced by non-conductive particles suspended in an electrolyte. 

The presence of insulating films over the surface of charged conducting particles would tend to have relatively little effect, since the charges would... 

From the above discussion it is apparent that while charge can cause particles to come together, it cannot be a significant factor in determining the force of adhesion with conductive particles. With perfect insulators, very high charge levels (corresponding to ps > 100 V/micron) can result in an effective force of adhesion. 

The technique is suitable for the analysis of non-conducting particles and for conducting particles when electrical double layers confer a suitable degree of electrical insulation. This is also discussed in Section 5.2.2. 

Note 6 Electric conductance of a nonconducting polymer can be achieved by dispersing conducting particles (e.g., metal, carbon black) in the polymer. The resulting materials are referred to as conducting polymer composites or solid polymer-electrolyte composites. 

The electrical conductivity of two-phase, incompatible polymer blends containing carbon black has been shown to depend on the relative affinity of the conductive particles to each of the polymer components in the blend, the concentration of carbon black in the filler-rich phase, and the structural continuity of this phase [82]. Hence, by judicious manipulation of the phase microstructure, these three-phase filled composites can exhibit double percolation behaviour. 

When gaseous odor molecules are absorbed by the polymer, the electrical conductivity of the polymer changes. Different gases affect conductivity in different ways. Other sensor coatings are polymers containing conductive particles of silver or graphite. 

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