[Wikipedia excerpt: ‘….An alkaline battery (IEC code: L) is a type of primary battery which derives its energy from the reaction between zinc metal and manganese dioxide. Compared with zinc-carbon batteries of the Leclanché cell or zinc chloride types, alkaline batteries have a higher energy density and longer shelf life, yet provide the same voltage. The alkaline battery gets its name because it has an alkaline electrolyte of potassium hydroxide instead of the acidic ammonium chloride or zinc chloride electrolyte of the zinc-carbon batteries. Other battery systems also use alkaline electrolytes, but they use different active materials for the electrodes….Alkaline batteries account for 80% of manufactured batteries in the US and over 10 billion individual units produced worldwide. In Japan alkaline batteries account for 46% of all primary battery sales. In Switzerland alkaline batteries account for 68%, in the UK 60% and in the EU 47% of all battery sales including secondary types. Alkaline batteries contain zinc and manganese dioxide (Health codes 1), which can be toxic in higher concentrations. However, compared to other battery types, the toxicity of alkaline batteries is moderate. Alkaline batteries are used in many household items such as MP3 players, CD players, digital cameras, toys, flashlights, and radios….Batteries with alkaline (rather than acid) electrolyte were first developed by Waldemar Jungner in 1899, and, working independently, Thomas Edison in 1901. The modern alkaline dry battery using the zinc/manganese dioxide chemistry was invented by the Canadian engineer Lewis Urry in the 1950s in Canada already before he started working for Union Carbide’s Eveready Battery division in Cleveland, OH, building on earlier work by Edison. On October 9, 1957, Urry, Karl Kordesch, and P.A. Marsal filed US patent (2,960,558) for the alkaline battery. It was granted in 1960 and was assigned to the Union Carbide Corporation…When introduced in the late 1960s, the zinc electrode of alkaline batteries (in common with the then ubiquitous carbon-zinc cells) had a surface film of mercury amalgam. Its purpose was to control electrolytic action at impurity sites, which would reduce shelf life and promote leakage. With reductions in mercury content being mandated by various legislatures, it became necessary to greatly improve the purity and consistency of the zinc….…Alkaline batteries are manufactured in standardized cylindrical forms interchangeable with zinc-carbon batteries, and in button forms. Several individual cells may be interconnected to form a true “battery”, such as those sold for use with flashlights and the 9 volt transistor-radio battery….A cylindrical cell is contained in a drawn stainless steel can, which is the cathode connection. The positive electrode mixture is a compressed paste of manganese dioxide with carbon powder added for increased conductivity. The paste may be pressed into the can or deposited as pre-molded rings. The hollow center of the cathode is lined with a separator, which prevents contact of the electrode materials and short-circuiting of the cell. The separator is made of a non-woven layer of cellulose or a synthetic polymer. The separator must conduct ions and remain stable in the highly alkaline electrolyte solution….The negative electrode is composed of a dispersion of zinc powder in a gel containing the potassium hydroxide electrolyte. The zinc powder provides more surface area for chemical reactions to take place, compared to a metal can. This lowers the internal resistance of the cell. To prevent gassing of the cell at the end of its life, more manganese dioxide is used than required to react with all the zinc. Also, plastic-made gasket is usually added to increase leakage resistance….The cell is then wrapped in aluminium foil, a plastic film, or rarely, ……..’ ].