Microstructure Evolution and Performance Enhancement of Sintered Aluminum Foils for Aluminum Electrolytic Capacitors

Sintered foils are currently being considered as a promising material for anode foils in capacitors due to their high specific capacitance and anti-buckling performance, which meet the requirements for capacitor winding. In this article, sintered foils with added starch were produced using a protective atmosphere sintering process. The effect of starch addition in the range of 0–50 vol% on the specific capacitance and anti-buckling performance of the sintered foils was evaluated. Scanning electron microscope (SEM) analysis confirmed the formation of the pores in the sintered foils due to the addition of starch. These pores play a crucial role in improving the specific capacitance and enhancing the anti-buckling performance of the sintered foils. However, excessive amounts of starch can have a negative impact on the specific capacitance of the sintered foils which initially decreased, then increased, and finally decreased with increasing starch content. On the other hand, the anti-buckling performance increased with increasing starch content. At 30 vol% starch addition, a high specific capacitance of 0.886 μ F/cm 2 and an anti-buckling performance of more than 120 times were obtained, meeting the requirements for anode foils in aluminum electrolytic capacitors. The specific capacitance of the sintered foils was predicted using the close-packed packing model, which can help establish a powder metallurgy method for preparing anode foil materials with high specific capacitance and anti-buckling performance for aluminum electrolytic capacitors. Graphical Abstract