Preparation of AgNWs@NiO–Co3O4 dopant material for an activated carbon thin-film electrode of pseudocapacitors

In this study, AgNWs@NiO–Co3O4 nanocomposites were synthesized through the hydrothermal method and used as dopant materials for activated carbon-based supercapacitors. Self-synthesized one-dimensional silver nanowires (AgNWs) with a diameter of 500 nm were used to grow NiO and Co3O4 on the AgNWs surface. The morphology and composition of the AgNWs@NiO–Co3O4 nanocomposite material were analyzed. The experimental results revealed that doping of AgNWs@NiO–Co3O4 nanocomposites can effectively increase the specific capacitance of supercapacitor. An ultrasonic spray coating was used to greatly reduce the weight of thin films, which were then employed to produce lightweight thin-film electrodes that induced the reaction with the electrolyte. The electrodes achieved a maximum specific capacitance of 706.95 F/g when activated carbon and AgNWs@NiO–Co3O4 nanocomposites were mixed at a 10:1 ratio. Moreover, the charge transfer resistance decreased from 1.5 to 0.3 Ω. Even after 5000 cycles of charge and discharge tests, 92.81% of the capacitance was retained, which was higher than the capacitance of 65.19% retained in an undoped sample. These results demonstrated that the activated carbon thin-film electrode doped with AgNWs@NiO–Co3O4 nanocomposites can effectively improve the capacitance and stability of the capacitor.