Ultra-high-voltage capacitor based on aluminum electrolytic–electrochemical hybrid electrodes

Low working voltage hinders the wide application of a single electrochemical capacitor, while the rapidly developing industry of electronic components urgently needs a kind of device combining the advantages of high voltage and energy capacity. This work successfully prepared a flexible packaging aluminum electrolytic–electrochemical hybrid capacitor with high working voltage and capacitance, using aluminum electrolytic capacitor anode foil as anode and activated carbon composite electrodes as cathode. The results show that the working voltage reaches 105 V. The single capacitance reaches 580 μF at a current of 100 mA cm⁻², which is double than that of the traditional aluminum electrolytic capacitors at the same size. The hybrid capacitor exhibits superior energy storage density and rapid charge–discharge capacity. The gravimetric energy density and volume energy density for the hybrid capacitor is 0.49 J g⁻¹ and 0.62 J cm⁻³, respectively. It also exhibits excellent cycling performance without obvious capacitance capacity fading. The increase in the energy density of the hybrid capacitor is mainly due to the use of aluminum electrolytic capacitor materials for the anode and the use of electrochemical capacitor material for the cathode, which increases the operating voltage and the specific capacitance.