Manganese dioxide cathodes

Chemistry. The alkaline cell derives its power from the reduction of the manganese dioxide cathode and the oxidation of the zinc anode. The reactions... 

The independent comparative testing of the experimental samples of the internally-made power sources of IGIC 1142 size and the Toshiba s L43 (both size designations stand for similar cell sizes) were carried out. It was shown that power sources containing manganese dioxide cathode obtained... 

The name Leclanche cell is given to the familiar primary system consisting of a zinc anode, manganese dioxide cathode and an electrolyte of ammonium chloride and zinc chloride dissolved in water. The alternative designation zinc-carbon ceir is broader and includes the so-called zinc chloride system which, due to a different electrolyte composition, is characterized by a different discharge mechanism. The Leclanche cell may be written as... 

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. 

Zn(OH)2 is soluble in the alkaline solution as [Zn(OH)3]- until the solution is saturated with K[Zn(OH)3]. In addition Zn(OH)2 can be dehydrated to ZnO. An enhanced power density (when compared with the - Leclanche cell) is accomplished by using particulate zinc (flakes) soaked with the alkaline electrolyte solution. This anode cannot be used as a cell vessel like in the Leclanche cell. Instead it is mounted in the core of the cell surrounded by the separator the manganese dioxide cathode is pressed on the inside of the nickel-plated steel can used as battery container. In order to limit self-discharge by corrosion of zinc in early cells mercury was added, which coated the zinc effectively and suppressed hydrogen evolution because of the extremely low exchange current density... 

Leclanche cell — Primary cell (-> Leclanche 1866) containing a manganese dioxide cathode in an aqueous electrolyte solution of NF14C1 (20 wt %) in a zinc beaker used as anode (negative electrode, negative mass). Gelatin is added to enhance the viscosity of the electrolyte solution. Electrode reactions are... 

Zinc perchlorate and magnesium perchlorate can be used as electrolytes in aqueous -> zinc and primary - magnesium batteries. For example, zinc perchlorate is used as an electrolyte in dry cells comprising zinc anodes and manganese dioxide cathodes. 

Ledanche cell (battery) one of the earliest practical non-rechargeable batteries (Georges-Lionel Leclanche, 1866). It uses a zinc anode (negative electrode) and a manganese dioxide cathode (positive electrode) with ammonium chloride solution as electrolyte. The initially liquid electrolyte... 

Lithium batteries with a manganese dioxide cathode are also used when reduction in size and weight is important, such as for powering 35 mm flash cameras. The lithium-manganese dioxide cell and reaction may be written as ... 

Leclanche s cells have been around for more than 100 years. They are also known as zinc/carbon cells or dry cells. They use a chemically produced manganese dioxide cathode (positive electrode), a zinc (foil or sheet) anode (negative electrode), and an aqueous electrolyte. Typical electrolyte mixtures include ammonium chloride and zinc chloride dissolved in water. The electrodes are separated by a cereal paste wet with electrolyte or a starch or polymer-coated absorbent kraft paper. The reactions... 

Manganese dioxide cathode with some metal impurities. 

Limiting the amount of metallic zinc in the anode formulation prevents deep discharge of the manganese dioxide cathode which was one of the most important problems with earlier constructions. A physical restriction of the cathode and the use of modified manganese dioxide containing lattice stabilizers contributed to the improvement of cycle life [11,12,13]. 

The first metal/air cell mentioned in the literature was a zinc/air cell constructed by Smee in 1840 [11]. In 1878, Maich [12], modified a Leclanch6 cell by replacing the conventional manganese dioxide cathode by a mixture of platinum and carbon powder. Ever since the work of Maich, various metals have been studied for use in this type of system in different applications. Among others, zinc, iron and aluminium have been considered to electric vehicles applications. It is, however, in the field of electric vehicles that most of the research has been conducted. 

The conducting polymer is roughly 1000 times more conductive than the traditionally used manganese dioxide cathode material and it penetrates more effectively into the porous metal-oxide anode structures, creating more robust capacitor structures. 

Alkaline cells are available worldwide in a variety of sizes and shapes. The term alkaline ceU is used to describe the specific cell containing zinc aUoy powder anode, nanostmc-tured electrolytic manganese dioxide cathode, and concentrated potassium hydroxide (KOH) electrolyte. The construction of the D-size cell is given in Fig. 1 and is typical of the constmc-tions of all alkaline cylindrical cells from the... 

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