An ultra-low loss and excellent high-frequency performance chip aluminum solid electrolytic capacitor with electropolymerization PEDOT cathode

The rapid advancement of artificial intelligence (AI) technology is creating new requirements for supply voltage stability and power conversion efficiency, necessitating electrolytic capacitors with conductive polymer cathode films. A study examines how different doping anions, pH levels, and current densities affect the constant-current electropolymerization of poly(3,4-ethylenedioxythiophene) (PEDOT) on poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) substrates. Highly doped PEDOT films with smooth surfaces and a conductivity of 313 S cm⁻¹ are obtained at pH 2 and 0.5 mA cm⁻² using dodecyl benzene sulfonate (DBS⁻) as a doping anion. A PEDOT:PSS conductive substrate is created on the dielectric surface of anodized aluminum foil. Low current density and then high current density electropolymerization of PEDOT cathodes on substrate allow for more efficient capacitors with high capacitance and low leakage current. Based on this, the chip capacitor is obtained with a capacitance of 80 μF cm⁻² level, a loss of 0.65 % at 100 Hz, an equivalent series resistance (ESR) of 4.16 mΩ at 100 kHz, and a leakage current of 0.8 μA at 16 V. This work is significant for the research of ultra-low loss and ESR chip aluminum solid electrolytic capacitors.