Chemical energy commercial batteries

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. 

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... 

During the operation of a galvanic cell a chemical reaction occurs at each electrode, and it is the energy of these reactions that provides the electrical energy of the cell. If there is an overall chemical reaction, the cell is referred to as a chemical cell. In some cells, however, there is no resultant chemical reaction, but there is a change in energy due to the transfer of solute from one concentration to another such cells are called concentration cells. Most, if not all, practical commercial batteries are chemical cells. 

Electrochemistry is the study of processes by which chemical energy is converted to electrical energy and vice versa. This branch of chemistry has numerous applications in today s increasingly technological world, such as for batteries, electronic components, and commercial electroplating. 

Mechanical and Chemical Stability. The materials must maintain their mechanical properties and their chemical structure, composition, and surface over the course of time and temperature as much as possible. This characteristic relates to the essential reliability characteristic of energy on demand. Initially, commercial systems were derived from materials as they are found in nature. Today, synthetic materials can be produced with long life and excellent stability. When placed in a battery, the reactants or active masses and cell components must be stable over time in the operating environment. In this respect it should be noted that, typically, batteries reach the consumer 9 months after their original assembly. Mechanical and chemical stability limitations arise from reaction with the electrolyte, irreversible phase changes and corrosion, isolation of active materials, and local, poor conductivity of materials in the discharged state, etc. 

Figures 30 and 31 refer to the excellent performance of this battery type (see Figure 31, high cell voltage of 3 V, ten times better mass-related energy content than for the lead-acid accumulator) such cells have not been commercialized up to now. This is not because of the problems to maintain the temperature—this is achieved by the waste heat—it is because the danger of crack formation and resulting catastrophic local chemical reactions that led to the fact that investigations with respect to electrotraction have been essentially abandoned.

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