Study of the H₂O/Al₂O₃ Interface and the Acting Mechanism of Water in the Working Electrolyte

Using a working electrolyte containing mixed solvents of ethylene glycol and N,N-dimethylformamide, this paper presents a study of the reactions on the H₂O/Al₂O₃ interface with sum frequency vibrational spectroscopy and the effects of different water content on the performance of the working electrolyte and an aluminum electrolytic capacitor and summarizes the rules of the variations in the performance parameters of the working electrolyte and aluminum electrolytic capacitor with respect to the water content. The results demonstrate that, when the water content is increased from 2.5 to 15%, the conductivity of the working electrolyte increased by 930 μS/cm, and the sparking voltage decreased by 27 V. Also, the increased water content causes lower oxidation efficiency and lower thermal stability. The leakage current of the aluminum electrolytic capacitor after high-temperature storage increases with an increase in the water content, and the attenuation rate of capacitor’s the low-temperature capacitance decreases with an increase in the water content.