The composition and structure of aluminum foil used for electrolysis are exquisite. For example, for anode foil, high purity is no longer required and is required to be as high as possible. In order to improve the initial corrosion point, mechanical strength, and performance of the dielectric oxide film, the foil should contain some impurities, and some alloy foils should be used.

Structurally, for low-voltage foils, a large proportion of cubic structures are not required, but for high-voltage foils, this structure is required to account for over 80% -90%. For cathode foil, in order to improve its specific capacity, alloy aluminum foil with irregular grain orientation and certain impurity content is required. The working electrolyte consists of three components: solvent, solute, and additive. For example, an electrolyte that has been used for a long time is composed of ethylene glycol, glycerol, boric acid, and ammonia.

With the development of Aluminum electrolytic capacitor, this electrolyte can no longer meet the requirements, so many new electrolytes have been produced to reduce the operating temperature range of the capacitor (such as -55 ℃ -125 ℃). The formula principles for these new electrolytes are:

① Mix two solvents to achieve complementarity.

② Two weak acids are used to provide the required two anionic groups.

③ Add alkali, such as organic amines, adjust the pH value and flash voltage of the electrolyte to change its resistivity.

④ Additives that improve the characteristics of electrolytes, such as phosphoric acid or its salts that prevent the hydration of alumina membranes, and dinitrobenzene that absorbs hydrogen gas. Ethylene oxide increases the flash voltage of the electrolyte.