Comparative analysis of separator materials for aluminum electrolytic capacitors: Tencel fiber outperforms Sisal and PPTA

Separators play a significant role in isolating the anode foil and cathode foil in capacitors to prevent short circuiting of the two poles resulting from contact. The physical and electrical properties of the separator have a decisive influence on the performance of the capacitor. Herein, we present an investigation and analysis of the physical and electrical properties of separators composed of cellulose fibers (Tencel), high-performance synthetic fibers (Poly-phenylene terephthalamide, abbreviated as PPTA), and those made of natural plant fibers (Sisal). Also, these separators were studied and compared under different beating degree conditions. The results indicate that the tightness of all three types of fibers gradually increases as the degree of raw fibrillation rises, leading to a gradual decrease in both the electrolyte absorption and the air permeability. The experimental results show that the overall performance of the capacitor using Tencel fiber separator is superior, the dielectric loss factor (1.01 ×1011 Ω·cm) is 87.5% lower than that of Sisal fiber separator, the capacitance (403.62 μF) is 1.4% higher than that of Sisal fiber separator, the absorption height (38 mm/10 min) is 90% higher than that of Sisal fiber separator, the leakage current (4.3 μA) is 10.4% lower than that of Sisal fiber 10.4% lower than Sisal fiber separator, equivalent series resistance (ESR) value (0.14 mΩ) 17.6% lower than Sisal fiber separator, and the best performance stability. Therefore, these results indicate that Tencel fiber can replace Sisal fiber as a better separator material for aluminium electrolytic capacitors.