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The type of manganese dioxide

The type of manganese dioxide (MnO2) and its quantity used in dry cells are mainly responsible for cell capacity. Performance characteristics depend on individual crystal structure, varying degrees of hydration, and the activity of the manganese dioxide. Manganese dioxide potentials are additionally affected by the pH of the electrolyte. Most zinc–carbon batteries are cathode limited. Four different types of manganese dioxide are applied in dry cells: (NMD alpha- and beta-structure), activated manganese dioxide (AMD), chemically synthesized manganese dioxide (CMD, delta-structure), and electrolytic manganese dioxide (EMD, gamma-structure). Activated manganese dioxide is prepared by chemical treatment of natural ore (roasting, sulfuric acid treatment). The CMD type may be obtained either as a by-product of an oxidation process with potassium permanganate or by the thermal decomposition of other manganese compounds followed by oxidation. Electrolytic manganese dioxide is obtained by anodic oxidation of manganese sulfate in hot sulfuric acid. Although more expensive, EMD has the advantage of yielding higher cell capacity with improved rate capability (for heavy or industrial applications), and its polarization is significantly lower compared to other types. Manganese dioxide (MnO2) has been successfully used as inexpensive and abundant battery material since its introduction in zinc–carbon batteries (with ammonium chloride electrolyte) by G. L. Leclanché in 1866. Initially, naturally occurring MnO2 was used, followed by chemically synthesized manganese dioxide, substantially improving the performance of Leclanché batteries. Later, the more efficient electrochemically prepared manganese dioxide (EMD) was applied, enhancing cell capacity and rate capability. The pioneering work of Herbert resulted in the first commercialization of the alkaline manganese dioxide–zinc battery in 1952, comprising a potassium hydroxide (KOH) electrolyte. Further improvements (e.g., design change, powder zinc anodes) were achieved by Union Carbide Corp. from 1960 to 1970, leading to a more powerful alkaline cell. The alkaline MnO2–Zn battery has become today's predominant primary battery system, having several advantages over its acidic electrolyte counterpart. Moreover, the primary battery was further developed by K. Kordesch into a rechargeable alkaline battery system produced in 1994. If you are looking for high quality, high purity and cost-effective manganese dioxide, or if you require the latest price of manganese dioxide, please feel free to email contact mis-asia.

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