High energy density PbO2/activated carbon asymmetric electrochemical capacitor based on lead dioxide electrode with three-dimensional porous titanium substrate

•High-capacity 3D-Ti/PbO2 electrode is electrodeposited.•The 3D-Ti/PbO2 electrode has large electrochemical active surface area.•An AEC is developed by using 3D-Ti/PbO2 electrode as positive electrode.•The 3D-Ti/PbO2/AC AEC exhibits a high level of energy density.

A PbO2/AC asymmetric electrochemical capacitor (AEC) with energy density as high as 49.4 Wh kg−1, power density of 433.2 W kg−1 and specific capacitance of 135.2 F g−1 was fabricated with PbO2 electrodeposited on three-dimensional porous titanium (3D-Ti/PbO2) and activated carbon. The high electrochemical active surface of 3D-Ti/PbO2 resulted in high specific capacity making it suitable for use as positive electrode in PbO2/AC AEC. The fabricated AEC demonstrated good power performance with an energy density conservation of 30 Wh kg−1 at power density of 2078 W kg−1. The fabricated AEC also showed excellent cycling stability with capacitance retention of 99.2% after 1000 cycles.