Zinc-manganese dioxide battery

Water is not used in the reaction. Therefore, these cells have a very high capacity, exceeding that of zinc—manganese dioxide batteries (Table 2). 

The button cells that provide the energy for watches, electronic calculators, hearing aids, and pacemakers are commonly alkaline systems of the silver oxide-zinc or mercuric oxide-zinc variety. These alkaline systems provide a vei y high energy density, approximately four times greater than that of the alkaline zinc-manganese dioxide battery. 

J K. Kordesch, W. Harer, Y. Sharma, R. Uji, K. Tomantschger, D. Freeman, Rechargeable, alkaline zinc manganese dioxide batteries, 33rd Int. Power Sources Svmp., Cherry Hill, NJ, June 13-16,1988, 440 51. 

K. Kordesch, S. Yuwei, Technology process of rechargeable alkaline zinc manganese dioxide batteries in Battery Bimonthly, 1995, 25, (Di-anchi Support Human Light Industry Research Institute). 

From the 1960s onward, alkaline zinc-manganese dioxide batteries started to be produced. They have appreciably better electrical performance parameters (see Section 19.4.3) but do not differ from Leclanche batteries in their operating features, are produced in identical sizes, and can be used interchangeably with them. Thus, a gradual changeover occurred and phaseout of the older system is now almost complete. 

Another example for reactions with the insertion of protons is the cathodic reduction of manganese dioxide, which occnrs dnring discharge of the positive electrodes in zinc-manganese dioxide batteries. This reaction can be formulated as... 

Only a few of the thousands of proprosed battery systems have been commercialized. A set of criteria can be established to characterize reactions suitable for use in selecting chemical systems for commercial battery development. Very few combinations can meet all of the criteria for a general purpose power supply. The fact that two of the major battery systems introduced more than 100 years ago, lead acid (rechargeable) and zinc—manganese dioxide (primary), are still the major systems in their category is indicative of the selection process for chemical reactions that can serve the battery marketplace. 

Cadmium, along with nickel, forms a nickel-cadmium alloy used to manufacture nicad batteries that are shaped the same as regular small dry-cell batteries. However, a major difference is that the nicads can be recharged numerous times whereas the common dry cells cannot. A minor difference between the two types of cells is that nicads produce 1.4 volts, and regular carbon-zinc-manganese dioxide dry-cell batteries produce 1.5 volts. 

The manufacture of secondary batteries based on aqueous electrolytes forms a major part of the world electrochemical industry. Of this sector, the lead-acid system (and in particular SLI power sources), as described in the last chapter, is by far the most important component, but secondary alkaline cells form a significant and distinct commercial market. They are more expensive, but are particularly suited for consumer products which have relatively low capacity requirements. They are also used where good low temperature characteristics, robustness and low maintenance are important, such as in aircraft applications. Until recently the secondary alkaline industry has been dominated by the cadmium-nickel oxide ( nickel-cadmium ) cell, but two new systems are making major inroads, and may eventually displace the cadmium-nickel oxide cell - at least in the sealed cell market. These are the so-called nickel-metal hydride cell and the rechargeable zinc-manganese dioxide cell. There are also a group of important but more specialized alkaline cell systems which are in use or are under further development for traction, submarine and other applications. 

Primary alkaline cells use sodium hydroxide or potassium hydroxide as tlie electrolyte. They can be made using a variety of chemistries and physical constructions. The alkaline cells of the 1990s are mostly of the limited electrolyte, dry cell type. Most primary alkaline cells are made sing zinc as the anode material a variety of cathode materials can be used. Primary alkaline cells are commonly divided into tW o classes, based on type of construction the larger, cylindrically shaped batteries, and the miniature, button-type cells. Cylindrical alkaline batteries are mainly produced using zinc-manganese dioxide chemistry, although some cylindrical zinc-mercury oxide cells are made. 

Zinc-Manganese Dioxide Batteries. The combination of a zinc anode and manganese dioxide cathode, which is the dominant chemistry in large cylindrical alkaline cells, is used in some miniature alkaline cells as well. Overall, this type of cell does not account for a huge share of the miniature cell market. It is used in cases where an economical power source is wanted and where the devices can tolerate the sloping discharge curve shown in Figure 2. 

Leclanche cells are the least expensive primary batteries. The first zinc-manganese dioxide cell was developed by Georges Leclanche in 1866. He developed the primary battery with an ammonium chloride and zinc chloride electrolyte, and with a natural Mn02 and carbon (usually acetylene black) cathode inserted into a zinc can. His name is still associated with this chemistry today. The battery reactions are given in Equation 10.1. 

The mode of presentation here will be to describe the more important batteries of the late 1990s according to three divisions. First, one sees three batteries (lead-acid, nickel-cadmium, and zinc-manganese dioxide) which, in various forms, have been in... 

Zinc-Manganese Dioxide. In 1866 Leclanche invented a galvanic cell in which the reduction of Mn02 is the cathodic reaction in the cell s discharge. The corresponding anodic dissolution reaction is the oxidation of zinc. The Leclanche cell is a (so-called) dry cell, i.e., the ammonium electrolyte is immobilized in the form of a paste. There are three forms of the zinc-manganese dioxide batteries ... 

K. Kordesch, Primary batteries - alkaline manganese dioxide/zinc batteries, in Comprehensive Treatise of Electrochemistry. Vol. 3, J. O M. Bockris, B. E. Conway, E. Yeager and R. E. White, editors. Plenum Press, New York, 1981, pp. 219-232. 

Figure 5. Performance of D-size zinc-manganese dioxide primary systems under 2.25 Q continuous test a) standard Leclanche cell (natural ore), b) high-power Leclanche cell (electrolytic MnOa), c) zinc chloride cell, d) alkaline manganese cell [1] (by permission of Arnold C.A. Vincent, B. Scrosati, Modern Batteries. An Introduction to Electrochemical Power Sources, 2nd edition, Edward Arnold, London, 1997).

Fig. 18. Dischaige curves for miniature zinc—silver oxide batteries (-), and zinc—manganese dioxide batteries (—) (21).

These batteries are the most widely used, also by virtue of their low cost. The anode is high-purity Zn and the cathode is battery-grade manganese dioxide. The electrolyte may be either a solution of ammonium chloride (Leclanche cell) or zinc chloride. The overall cell reaction may be written, in simplified form, as ... 

Alkaline cells use the same zinc-manganese dioxide couple as Leclanche cells. However, the ammonium chloride electrolyte is replaced with a solution of about 30 wt% potassium hydroxide (KOH) to improve ionic conductivity. The ceU reactions are identical to those above, but the battery construction is rather different (Figure 9.7). The negative material is zinc powder, and the anode (negative terminal) is a brass pin. The positive component is a mixture of Mn02 and carbon powder that surrounds the anode. A porous cylindrical barrier separates these components. The positive terminal (cathode) is the container, which is a nickel-plated steel can. 

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