Pre-crystallized interface anodization: a novel strategy for energy-efficient fabrication of high-performance...

Due to the rapid development of emerging fields such as electric vehicles and artificial intelligence, the market has set new requirements for the performance and pricing of aluminum electrolytic capacitors. This paper presents the Pre-Crystallized Interface Anodization (PCIA) method, which incorporates a pretreatment sequence of boiling-heat treatment- boiling-phosphoric acid treatments. The method generates additional crystalline aluminum oxide at the interface between hydrated aluminum oxide and aluminum oxide through pretreatment. The dense oxide film inhibits the hydration that occurs at the interface during anodization, reducing defects and improving the performance of the oxide film. The additional aluminum oxide and hydrated aluminum also helps to reduce the energy consumption during the anodizing process, lowering the electricity consumption of the process. Compared with aluminum foils anodized by the traditional process, those treated under optimized PCIA conditions exhibit a reduction in electricity consumption of up to 25.1%, along with an increase in the product of specific capacitance and withstanding voltage (CV value) of up to 13.0%, and a significant reduction in losses. The preheat treatment anodizing method accomplishes the performance enhancement and cost reduction of aluminum electrolytic capacitors through uncomplicated treatment, which is a new anodizing method with broad prospects.