Author: admin
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Growth of Nuclei
Early Growth of NucleiIn this section, we examine initial growth of deposits from distinct nuclei. The distinguishing factor in early growth is that the nuclei are far enough apart to behave independently. Under such conditions, the total deposition current can be estimated by summing the contributions from the individual nuclei. Here we consider both kinetically…
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Nucleation Rates
Above we treated the thermodynamics associated with stable cluster formation. We now turn our attention to the rate at which nuclei are formed. In doing this, we restrict ourselves to the classical expressions for the nucleation rate attributed to Volmer and Weber, noting that similar expressions can be derived from atomistic theory. Please refer to…
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Formation of Stable Nuclei
The formation of new sites or nuclei from which deposition may occur is called nucleation, and it is a critical aspect of electrodeposition. The number and type of nuclei strongly influence the morphology of the deposit. Both the growth rate of the deposit and the rate of nucleation increase with increasing overpotential. If the nucleation…
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Electrodeposition Fundamentals
To this point, we have treated electrodeposition in a macroscopic way. However, deposit morphology and properties vary dramatically with the conditions under which the deposition takes place as illustrated in Figure 13.2, where current density is varied. In order to understand these different morphologies, we need to explore the fundamental processes that take place during…
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Faraday’s Law and Deposit Thickness
An important aspect of electrodeposition is that the total amount deposited is directly related to the amount of charge passed in carrying out the desired reaction, and hence to the thickness of the plated layer. The mass of the deposit is (13.1)where Q is the charge passed due to the plating reaction. Assuming that the…
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Overview
Electrodeposition is a shortened form of “electrolytic deposition,” which is the use of an electrolytic cell to deposit metal(s) or other material(s) on the target electrode. Therefore, like other electrolytic processes, electrodeposition consumes power to produce the desired product. For the moment, we focus our discussion on the electroplating of metals from aqueous solutions. Figure…
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Fuel-Cell Hybrid Systems for Vehicles
An alternative to the ICE is a fuel-cell power source, typically operating with hydrogen as the fuel. A key advantage is that emissions of carbon are eliminated as well as criteria pollutants. There are a few important distinctions to be made for fuel-cell hybrids. First, the fuel cell, like the battery, generates DC electrical power;…
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Batteries for Full-Hybrid Electric Vehicles
In this section, we are interested in hybrids where energy can be recovered during braking and where energy from the RESS can be used to propel the vehicle (so-called full hybrids). Full-hybrid vehicles span a range of architectures, including both the parallel and series architectures discussed previously. They have many advantages over a start–stop hybrid,…
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Start–Stop Hybrid
As we consider the energy storage requirements for the start–stop hybrid, it is important to know the power required as a function of time. The intended driving schedule and many of the specifics for the vehicle are not needed for design of the energy storage system for this type of hybrid, since the RESS does…
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Hybrid Vehicle Architectures
There are many architectures used in hybrid systems. We will not attempt to cover them extensively; rather, our objective is to review some typical architectures and to provide a broad overview of terminology. In subsequent sections, we will explore in more detail electrochemical devices for energy storage for specific hybrid architectures. Because there are many…