Alkaline Manganese-Zinc Batteries

Compared with the Leclanche batteries, the alkaline manganese-zinc batteries (often labeled simply as alkaline batteries ) offer better performance at high discharge currents and lower temperatures and a better shelf life. They are more expensive than the Leclanche batteries, but their cost per unit of energy is competitive while sufficient raw materials for a mass production of these batteries are available. Their capacity at 

The active material of the cathode (6) is pressed into the inner surface of a steel can (2). A separator (3) of unwoven plastic fabric and/or cellophane is inserted into the can, which contains the electrolyte and prevents internal shortings. A petal-shaped brass current collector is in the central part of the cell. The space between the separator and the current collector is filled with the anode paste (7), which consists of the alkaline solution gelled with carboxymethyl cellulose (CMC) and zinc powder. An additional amount of pure electrolyte (9) is inside the current collector. To provide exchangeability with conventional cylindrical cells, the upper side of the cell has a bulge (1) that serves as the positive terminal. The bottom (13) serves as the negative terminal. To improve internal contact a pressure spring (12) is often used. The can is inserted into a metal jacket (4) with the insulator (5). 

Alkaline batteries are used in many household items. This includes MP3 players, CD players, digital cameras, pagers, toys, lights, and radios, to name a few. The most widespread production and application have cylindrical alkaline batteries which now can be found literally in every household. To provide interchangeability their size is standardized with that of Leclanche batteries. Most commonly the following sizes are used  

2 Rechai eable Alkaline Manganese-Zinc Batteries 

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From the 1960s onward, alkaline manganese-zinc batteries started to be produced. They have appreciably better electrical performance parameters but do not differ in their operating features from the Leclanche batteries, are produced in identical sizes, and can be used interchangeably with them. Thus, a gradual changeover occurred and the phase-out of the older system is now almost complete. 

Figure 2.2. Schematic of an alkaline manganese-zinc battery.

In batteries with metallic container one terminal must be electrically insulated from it. In low-temperature batteries for this purpose rubber or plastic gaskets are used, which provide a sufficient effective sealing of joints. But in sealed batteries with an alkaline electrolyte solution (e.g., in cylindrical alkaline manganese-zinc batteries), after some time the alkaline solution begins to creep around most sealing gaskets and then forms on the outside white patches of alkali carbonates. 

K. Kordesch et al., Rechaigeable Alkaline Zinc-Manganese Dioxide Batteries and T. Messing et al., Improved Components for Rechaigeable Alkaline Manganese-Zinc Batteries, 36th Power Sources Conference, Palisades Institute for Research Services, Inc., New York, 1994. 

The initial voltage of an alkaline-manganese dioxide battery is about 1,5 V. Alkaline-manganese batteries use a concentrated alkaline aqueous solution (typically in the range of 30-45 % potassium hydroxide) for electrolyte. In this concentrated electrolyte, the zinc electrode reaction proceeds, but if the concentration of the alkaline solution is low, then the zinc tends to passivate. 

Mn02 is used for the same purpose as the cathode active material in lithium-manganese dioxide (Li - Mn02) batteries it has been used for a long time in zinc-carbon and alkaline-manganese dioxide batteries, which are aqueous-electrolyte systems. 

Alkaline manganese dioxide batteries have been around since 1959. They are usually known as alkaline batteries. They are a variation of Leclanche s cells. They use an electrolyte produced manganese dioxide as cathode (to improve its purity and increase the capacity of the cell), powdered zinc as anode (to provide a larger surface area for the reaction), and a highly... 

The term primary battery is used to describe any single use battery system. These include, amongst others, alkaline-manganese, zinc-carbon, lithium, mercuric oxide and zinc-air chemistries. Primary batteries are lightweight and convenient, relatively inexpensive and eonsequently are used by households throughout the world to power portable electrical and electronic devices, radios, torches, toys and a whole host of other every day appliances. 

FIGURE 3.15 Discharge characteristics of a 9-volt battery subjected to a 100 ms pulse (smoke detector pulse tests) (a) zinc-carbon battery (b) and (c) zinc/alkaline/ manganese dioxide battery. 

Increases in the energy density of primary hatteries has tapered off during the past decade as the existing battery systems have matured and the development of new higher energy batteries is limited by the lack of new and/or untried battery materials and chemistries. Nevertheless, advances have been made in other important performance characteristics, such as power density, shelf life and safety. Examples of these recent developments are the high power zinc/alkaline/manganese dioxide batteries for portable consumer electronics, the improvement of the zinc/air battery and the introduction of new lithium batteries. 

TABLE 8.10 ANSI Standards for Zinc-Carbon and Alkaline-Manganese Dioxide Batteries... 

Zinc-carbon batteries Alkaline-manganese dioxide batteries... 

Miniature button-type batteries, using the same zinc/alkaline-manganese dioxide chemistry as cylindrical cells, compete with other miniature battery systems such as mercuric oxide, silver oxide, and zinc/air. Table 10.2 shows the major advantages and disadvantages of miniature alkaline-manganese dioxide batteries in comparison to other miniature batteries. 

Li/FeS 1.5 Replacement for conventional zinc-carbon and alkaline-manganese dioxide batteries higher power capability than conventional batteries and better low-temperature performance and storability. Currently available in AA size as a direct replacement for alkaline-manganese... 

Li/FeS2 batteries are now manufactured in a cylindrical configuration. These batteries have better high-drain and low-temperature performance than the zinc/alkaline-manganese dioxide batteries. The performance of these two systems on constant-current discharge at various discharge rates, in the AA size, is compared in Fig. 14.76. 

RECHARGEABLE ZINC/ALKALINE/ MANGANESE DIOXIDE BATTERIES... 

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