Composition and performance of electrolyte for wide-temperature aluminum electrolytic capacitors

Wide temperature electrolyte is one of the core materials of aluminum electrolytic capacitors. In this review, we systematically compare the temperature resistance of different series of electrolytes and explores the change rule of each component of electrolyte solvent, solute, and additives on the performance of aluminum electrolytic capacitors. Current literature reports that the highest applicable temperature of aluminum electrolytic capacitors is up to 135 °C and the lowest applicable temperature is up to −55 °C. Conductive polymers with high-boiling point substances as additives are conducive to improving the high-temperature resistance of electrolyte performance. Low melting point substances such as sulfoxides and ethylamines are beneficial in reducing the melting point of the electrolyte, so that the electrolyte can work at lower temperatures. Reasonable use of anti-corrosion, agents, hydrogen eliminators, hydration-proofing agents, and stabilizers can extend the service life of capacitors. Phosphoric acid, hypophosphite, and phosphate can be used as both hydration-proofing and stabilizing agents, which play a vital role in prolonging the life of capacitors. This paper provides ideas and suggestions for the research of wide-temperature electrolytes for aluminum electrolytic capacitors.