Cells secondary

Nickei-metal-hydride batteries have become popular as rechargeable cells. The design is quite similar to the Ni-Cd cell, but nickel-metal-hydride cells are less prone to memory effects during the life of the battery. Such advances in battery technology are driven by rising demand for portable electronic devices like digital cameras. 

Lead-add storage batteries account for 88% of all lead consumed annually in the United States. 

Although these equations do not show it explicitly, the electrolyte for this battery is sulfuric acid. We can infer this from the presence of hydrogen sulfate ions (HS04 ) in the equations sulfate ion is converted to HSO4 under the highly acidic conditions of the battery. Because of the importance of sulfuric acid in these batteries, they are sometimes referred to as lead-acid storage batteries. 

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Fuel cells involve use of gaseous reactants to produce electricity - most often H2-O2 within a porous electrode. Secondary cells are rechargeable. The most important systems are... 

PATTERIES - SECONDARY CELLS - OTTiER] (Vol 3) Iron-chromium-mckel alloys... 

These ZEV vehicles are envisioned to be electric battery vehicles (see Batteries, secondary cells-other). The California fleet average standards are to be met by spiling combinations of various classes of vehicles. Manufacturers must certify their new cars in one of the categories shown. The sales weighted average for a given year must then be at or below the standard shown in Table 8. 

Secondary Lead. The emphasis in technological development for the lead industry in the 1990s is on secondary or recycled lead. Recovery from scrap is an important source for the lead demands of the United States and the test of the world. In the United States, over 70% of the lead requirements are satisfied by recycled lead products. The ratio of secondary to primary lead increases with increasing lead consumption for batteries. WeU-organized collecting channels are requited for a stable future for lead (see BATTERIES, SECONDARY CELLS Recycling NONFERROUS METALS). 

Uses. Nickel nitrate is an intermediate in the manufacture of nickel catalysts, especially those that are sensitive to sulfur and therefore preclude the use of the less expensive nickel sulfate. Nickel nitrate also is an intermediate in loading active mass in nickel—alkaline batteries of the sintered plate type (see Batteries, SECONDARY cells). Typically, hot nickel nitrate symp is impregnated in the porous sintered nickel positive plates. Subsequendy, the plates are soaked in potassium hydroxide solution, whereupon nickel hydroxide [12054-48-7] precipitates within the pores of the plate. 

When nickel hydroxide is oxidized at the nickel electrode in alkaline storage batteries the black trivalent gelatinous nickel hydroxide oxide [12026-04-9], Ni(0H)0, is formed. In nickel battery technology, nickel hydroxide oxide is known as the nickel active mass (see Batteries, secondary cells). Nickel hydroxide nitrate [56171-41-6], Ni(0H)N02, and nickel chloride hydroxide [25965-88-2], NiCl(OH), are frequently mentioned as intermediates for the production of nickel powder in aqueous solution. The binding energies for these compounds have been studied (55). 

Cadmium hydroxide is the anode material of Ag—Cd and Ni—Cd rechargeable storage batteries (see Batteries, secondary cells). Cadmium sulfide, selenide, and especially teUuride find utiUty in solar cells (see Solarenergy). Cadmium sulfide, Hthopone, and sulfoselenide are used as colorants (orange, yellow, red) for plastics, glass, glazes, mbber, and fireworks (see Colorants for ceramics Colorants forplastics Pigments). 

The charging process should only be applied for secondary cells, because the electrochemical reactions are reversible, in contrast to primary cells. Charging of primary cells, may lead to electrochemical... 

The discharge rate C is defined by the discharge current and the nominal capacity of the secondary cell. It is equal to the reciprocal value of the discharging time ... 

In the older battery literature the term separator is frequently used very loosely, to include all nonmetallic solid components between the electrodes, such as supporting structures for active materials (tubes, gauntlets, glass mats), spacers, and separators in a narrow sense. In this section, only the last of these, the indispensable separating components in secondary cells, will be termed separators , distinguished from the others by their microscopically small pores, i.e., with a mean diameter significantly below 0.1 mm. 

Until about 1880 the lead-acid battery was exclusively then subject of scientific study. Possible commercial utilization lacked suitable charging processes secondary cells had to be charged by means of the primary cells already known at that time. 

Secondary cells are galvanic cells that must be charged before they can be used this type of cell is normally rechargeable. The batteries used in portable computers and automobiles are secondary cells. In the charging process, an external source of electricity reverses the spontaneous cell reaction and creates a nonequilibrium mixture of reactants. After charging, the cell can again produce electricity. 

Practical galvanic cells can be classified as primary cells (reactants are sealed inside in a charged state), secondary cells (can be recharged), and fuel cells. 

Xylan-type polysaccharides are the main hemicellulose components of secondary cell walls constituting about 20-30% of the biomass of dicotyl plants (hardwoods and herbaceous plants). In some tissues of monocotyl plants (grasses and cereals) xylans occur up to 50% [6j. Xylans are thus available in huge and replenishable amoimts as by-products from forestry, the agriculture, wood, and pulp and paper industries. Nowadays, xylans of some seaweed represent a novel biopolymer resource [4j. The diversity and complexity of xylans suggest that many useful by-products can be potentially produced and, therefore, these polysaccharides are considered as possible biopolymer raw materials for various exploitations. As a renewable resource, xylans are... 

Glucomannans (GM) and galactoglucomannans (GGM), common constituents of plant cell walls, are the major hemicellulosic components of the secondary cell walls of softwoods, whereas in the secondary cell walls of hardwoods they occur in minor amounts. They are suggested to be present together with xylan and fucogalactoxyloglucan in the primary cell walls of higher plants [192]. These polysaccharides were extensively studied in the 1960s [6,193]. 

As plant cells grow, they deposit new layers of cellulose external to the plasma membrane by exocytosis. The newest regions, which are laid down successively in three layers next to the plasma membrane, are termed the secondary cell wall. Because the latter varies in its chemical composition and structure at different locations around the cell, Golgi-derived vesicles must be guided by the cytoskeleton... 

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