Zinc–carbon batteries were the first commercial dry batteries, developed from the technology of the wet Leclanché cell. They made flashlights and other portable devices possible, because the battery provided a higher energy density at a lower cost than previously available cells. A zinc–carbon battery (or carbon zinc battery in U.S. English) is a that provides from the between (Zn) and (MnO2) in the presence of an The container of the zinc–carbon dry cell is a zinc can (anode). The bottom and sides of the can contains a paper separator layer which is impregnated with ammonium chloride () along with a to form an aqueous electrolyte paste. The. In a zinc–carbon dry cell, the outer zinc container is the negatively charged terminal. Ammonium chloride electrolyteThe zinc is by the, (Cl ) into ZnCl2, via the following Manufacturers recommend storage of zinc–carbon batteries at room temperature; storage at higher temperatures reduces the expected. Zinc–carbon batteries may be frozen without damage; manufacturers recommend that they be. By 1876, the wet was made with a compressed block of manganese dioxide. In 1886, patented a "dry" version by using a casing made of zinc sheet metal as the and a paste of (and later, powder). Zinc–carbon batteries have a lower per unit cost and are often used as power for appliances that consume little energy, like for television, clocks, and. Zinc-carbon batteries were in common use with hand-cranked phones,. The zinc-chloride cell, frequently referred to as a heavy-duty, extra-heavy-duty, super-heavy-duty, or super-extra-heavy-duty battery, is an improvement on the original zinc–carbon cell, using purer chemicals and giving a longer service life and steadier voltage.