Nickel hydrogen, secondary

Nickel-hydrogen secondary batteries (still under development, limited use in satellites)... 

There are two major types of household batteries (a) Primary batteries are those that cannot be reused. They include alkaline/manganese, carbon-zinc, mercuric oxide, zinc-air, silver oxide, and other types of button batteries, (b) Secondary batteries are those that can be reused secondary batteries (rechargeable) include lead-acid, nickel-cadmium, and potentially nickel-hydrogen. 

Nickel—hydrogen batteries offer long cycle life that exceeds that of other maintenance-free secondary battery systems and accordingly makes it suitable for many space applications. Three types of separator materials have been used for aerospace Ni—H2 cells— asbestos (fuel-cell-grade asbestos paper), Zircar (untreated knit ZYK-15 Zircar cloth),and nylon. 

The curves displayed in Figure 9 summarize the results obtained for the nickel-hydrogen complex. The DFT energy curve for the EE-approach (upper left) resembles that resulhng from our SCF calculations (Fig. 6, lower left), with again a minimum around 1.2 A, except that now the curve shows more structure, with a secondary minimum around 3.2 A. The bond length of Ha (curve below) does not show any increase for this secondary minimum (physisorption), but for the main minimum it reaches a maximum that is much larger than in the SCT calculations (Fig. 7, lower left),... 

The nickel-based systems have traditionally included the following systems -nickel-iron (Ni/Fe), nickel-cadmium (NiCd), nickel metal hydrides (NiMH), nickel hydrogen (Ni/H2), and nickel-zinc (Ni/Zn). Of these, the metal hydride chemistry has been the most successful in the secondary battery market. AU nickel systems are based on the use of a nickel oxide active material (undergoing one valence change from charge to discharge or vice-versa). The electrodes can be pocket type, sintered type, fibrous type, foam type, pasted type, or plastic roll-bonded type. All systems use an alkaline electrolyte, KOH. 

The vented-type battery needs to perform water addition in which water consumed by electrolysis is periodically added. However, in recent years, the vented-type nickel-cadmium secondary battery which has reduced the water addition frequency is produced commercially for trains and the like. The battery controls the electrolysis of the water under float charging by using the pasted-type cadmium electrode which has a high hydrogen overpotential characteristic for the negative electrode. 

A nickel-cadmium secondary battery with the type of the gas recombination by catalyst in which oxygen and hydrogen gas generated in the end of charging are made to react and return to water by providing a catalyst to the vent valve is used partly. 

Nickel/cadmium batteries (line 8 in Table 1.1) have been in technical use nearly as long as lead-acid batteries. They belong to a whole family of secondary batteries that are based on aqueous, but alkaline electrolyte, usually diluted potassium hydroxide. Nickel/cadmium, nickel/hydrogen, and nickel/metal hydride batteries are the most important members of this group. A further common feature of these battery systems is that they employ the nickel-hydroxide electrode as the positive one. Some of their basic features will be described in the following. 

In battery systems based on aqueous electrolyte, water decomposition, which occurs above a cell voltage of 1.23 V, is such an unavoidable secondary reaction. But under certain conditions the resulting water loss can be avoided, and the system is used as a sealed one, as achieved with sealed nickel/cadmium, nickel/hydrogen, and nickel/metal hydride batteries. In lead-acid batteries corrosion is an additional unwanted secondary reaction with the consequence that lead-acid batteries cannot be made virtually sealed, but must have a valve, and a certain water loss cannot be prevented. 

As with the primary battery systems, significant performance improvements have been made with the older secondary battery systems, and a number of newer types, such as the silver-zinc, the nickel-zinc, nickel-hydrogen, and lithium ion batteries, and the high-temperature system, have been introduced into commercial use or are under advanced development. Much of the development work on new systems has been supported by the need for high-performance batteries for portable consumer electronic applications and electric vehicles. Figure 22.1 illustrates the advances achieved in and the projections of the performance of rechargeable batteries for portable applications. 

Of the conventional secondary systems, the nickel-iron and the vented pocket-type nickel-cadmium batteries are best with regard to cycle life and total lifetime. The nickel-hydrogen battery developed mainly for aerospace applications, has demonstrated very long cycle life under shallow depth of discharge. The lead-acid batteries do not match the performance of the best alkaline batteries. The pasted cells have the shortest life of the lead-acid cells the best cycle life is obtained with the tubular design, and the Plante design has the best lifetime. 

The most expensive of the conventional-type secondary batteries are the silver batteries. Their higher cost and low cycle life have limited their use to special applications, mostly in the military and space applications, which require their high energy density. The nickel-hydrogen system is more expensive due to its pressurized design and a relatively limited production. However, their excellent cycle life under conditions of shallow discharge make them attractive for aerospace applications. The cost of cylindrical lithium ion batteries has been decreasing rapidly as production rates have increased and has recently been stated to be S1.22/Wh. ... 

Nickel-hydrogen and silver-hydrogen secondary batteries 19/15... 

SAFT Socidte des Accumulateurs, Fixes et de Trac-lion, 156 Avenue de Metz, 93230 Romainville Secondary batteries, nickel-hydrogen, cuprous chloride, nickel-cadmium, lithium-manganese dioxide thermal cells, nickel-metal hydride secondary, sodium-nickel chloride secondary. See also SAFT (UK) and SAFT (US). (Chloride Alkad is now part of SAFT). 

Yardney Electric Corporation, Power Sources Division, 3850 Olive Street, Denver 80207, Colorado Secondary batteries, nickel-hydrogen, silver-zinc, silver—cadmium, nickel-zinc. 

P-Phenylethylamine is conveniently prepared by the hydrogenation under pressure of benzyl cyanide with Raney nickel catalyst (see Section VI,5) in the presence of either a saturated solution of dry ammonia in anhydrous methyl alcohol or of liquid ammonia the latter are added to suppress the formation of the secondary amine, di- P phenylethylamine ... 

Reduction. Most ketones are readily reduced to the corresponding secondary alcohol by a variety of hydrogenation processes. The most commonly used catalysts are palladium, platinum, and nickel For example, 4-methyl-2-pentanol (methyl isobutyl carbinol) is commercially produced by the catalytic reduction of 4-methyl-2-pentanone (methyl isobutyl ketone) over nickel. 

---