Voltaic cells commercial

Voltaic cells are found in many aspects of our life, as convenient and reliable sources of electrical energy, the battery. Batteries convert stored chemical energy to an electrical current to power a wide array of different commercial appliances radios, portable televisions and computers, flashlights, a host of other useful devices. 

A voltaic cell (a) is converted to an electrolytic cell (b) by attaching a battery with a voltage sufficiently large to reverse the reaction. This process underlies commercially available rechargeable batteries. 

Table 21.1 lists the voltages of some commercial and natural voltaic cells. Next, we ll see how to measure cell potential. 

An electrochemical cell can be defined as two conductors or electrodes, usually metallic, immersed in the same electrolyte solution, or in two different electrolyte solutions which are in electrical contact. Electrochemical cells are classed into two groups. A galvanic (sometimes, voltaic) cell is one in which electrochemical reactions occur spontaneously when the two electrodes are connected by a conductor. These cells are often employed to convert chemical energy into electrical energy. Many types are of commercial Importance, such as the lead-acid battery, flashlight batteries, and various fuel cells. An electrolytic cell is one in which chemical reactions are... 

Investigations of non-aqueous electrolyte solutions for application in photo-electrochemical liquid junction cells have only just begun and no predictions concerning their use in commercial cells can be made at present. The better-developed solid-state technologies have resulted in three lines of approach, based on different photovoltaic materials. These were described recently by Johnston in his monograph Solar Voltaic Cells as established technologies for different... 

Although any spontaneous redox reaction can serve as the basis for a voltaic cell, making a commercial battery that has specific performance characteristics can require considerable ingenuity. The substances oxidized at the anode and reduced by the cathode determine the voltage, and the usable life of the battery depends on the quantities of these substances packaged in the battery. Usually a barrier analogous to the porous barrier of Figure 20.6 separates the anode and cathode half-cells. 

Counting Electrons Coulometry and Faraday s Law of Electrolysis 21-7 Commercial Applications of Electrolytic Cells Voltaic or Galvanic Cells 21-8 The Construction of Simple Voltaic Cells... 

Table 21.1 lists the voltages of some commercial and natural voltaic cells. 

The next several sections describe battery cells, or voltaic cells (also called galvanic cells). These are a kind of electrochemical cell. An electrochemical cell is a system consisting of electrodes that dip into an electrolyte and in which a chemical reaction either uses or generates an electric current. A voltaic, or galvanic, cell is an electrochemical cell in which a spontaneous reaction generates an electric current. An electrolytic cell is an electrochemical cell in which an electric current drives an otherwise nonspontaneous reaction. In the next sections, we will discuss the basic principles behind voltaic cells and then explore some of their commercial uses. 

Voltaic cells are used commercially as portable energy sources (batteries). In addition, the basic principle of the... 

Solar voltaic cells based on crystalline silicon have operated with a 30% efficiency for experimental cells and 15-20% for commercial units available in 2008, at a cost of around 15 cents/kWh, compared to 4-7 cents/kWh for fossil fuel-fired power plants and 6-9 cents for those fired by biomass. Costs of photovoltaic electricity have shown a continuous downward trend. Part of the high cost in the past has resulted from the fact that the silicon used in the cells must be cut as small wafers from silicon crystals for mounting on the cell surfaces. Significant advances in costs and technology are being made with thin-fllm photovoltaics, which use an amorphous silicon alloy. These cells are only about half as efficient as those made with crystalline silicon, but cost only about 25% as much. A newer approach to the design and construction of amorphous silicon film photovoltaic devices... 

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