Zinc-Manganese Dioxide

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

Alkaline cells offer the highest energy density (more energy per given volume) of any zinc-manganese dioxide cell, and the manufacturers continue to improve on performance. In 1998, Duracell intro-... 

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, L. Binder, W. Taucher, C. Faistauer, J. Daniel-lvad, The rechargeable alkaline-zinc manganese dioxide system, Power Source 14, (Eds. Attewell, T. Keily), Internatl Power Sources Committee, 1993. 

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). 

Soon it became evident that the zinc anode, working in both cases under capacity-limiting conditions, causes severe troubles too. Whereas in the zinc/air system the anode automatically limits the discharge (because access to oxygen from the air is practically unlimited), the anode limitation in zinc/manganese dioxide cells has another reason Kordesch and co-workers... 

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. 

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