Galvanic cell A device in which chemical

Galvanic cell A device in which chemical energy from a spontaneous redox reaction is changed to electrical energy that can be utilized for power. 

We now have covered all the essential characteristics of a galvanic cell, a device in which chemical energy is changed to electrical energy. (The opposite process, electrolysis, will be considered in Section 11.7.)... 

Galvanic cell a device in which chemical energy is converted spontaneously to electrical energy by means of oxidation-reduction reaction. 

Electrochemistry is the area of chemistry concerned with the interconversion of chemical and electrical energy. Chemical energy is converted to electrical energy in a galvanic cell, a device in which a spontaneous redox reaction is used to produce an electric current. Electrical energy is converted to chemical energy in an electrolytic cell, a cell in which an electric current drives a nonspontaneous reaction. It s convenient to separate cell reactions into half-reactions because oxidation and reduction occur at separate electrodes. The electrode at which oxidation occurs is called the anode, and the electrode at which reduction occurs is called the cathode. 

To understand the basic principles of operation of an energy conversion or storage device it is important to know what an electrochemical cell is. Basically, it is a device in which a chemical reaction either generates or is caused by an electric current. A galvanic cell is an electrochemical cell in which a spontaneous chemical reaction is used to generate an electric current. An electrolytic cell, in turn, is an electrochemical cell in which a reaction is driven in its nonspontaneous direction by an externally applied electric current. There are three types of galvanic cell the primary, the secondary, and the fuel cell [5,6]. 

Fuel cells, like batteries, are a variety of galvanic cells, that is, devices in which two or more electrodes (electronic conductor) are in contact with an electrolyte (ionie conductors). Another variety of galvanic cells are electrolyzers in which electric current is used to generate chemicals in a process that is the opposite of those oceurring in fuel cells and involving the conversion of electrical to chemical energy. 

In some instances, however, pai t of the chemical energy bound in relatively high-enthalpy compounds can be converted directly to electricity as these reactants are converted to produc ts of lower enthalpy (galvanic action). A process in the opposite direc tion also is possible for some systems an elec tric current can be absorbed as the increased chemical energy of the higher-enthalpy compounds (electrolytic action). The devices in which electrochemical energy conversion processes occur are called cells. 

A galvanic cell, also called a voltaic cell, is a device that converts chemical energy to electrical energy. The key to this invention is to prevent the reactants in a redox reaction from coming into direct contact with each other. Instead, electrons flow from one reactant to the other through an external circuit, which is a circuit outside the reaction vessel. This flow of electrons through the external circuit is an electric current. 

Fuel cells (FCs) are electrochemical devices that directly convert fuel energy into electricity without the need for a thermal cycle. They are essentially galvanic cells in which the electrodes only collect and convey electrical charges, but (unlike in the Volta pile and all other electric cells and batteries) they do not participate in the electrochemical reaction, since they are chemically and electrochemically inert conductors (amorphous carbon, sintered nickel oxide, etc.). 

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