Porous NiO/Ag composite film for electrochemical capacitor application

A highly porous NiO/Ag composite film is prepared by the combination of chemical bath deposition and silver mirror reaction. The as-prepared NiO/Ag composite film has an interconnecting reticular morphology made up of NiO flakes with highly dispersed Ag nanoparticles of about 6 nm. The pseudocapacitive behavior of the NiO/Ag composite film is investigated by cyclic voltammograms (CV) and galvanostatic charge-discharge tests in 1 M KOH. The NiO/Ag composite film exhibits weaker polarization, higher specific capacitance and better cycling performance as compared to the unmodified porous NiO film. The specific capacitance of the porous NiO/Ag composite film is 330 F g−1 at 2 A g−1 and 281 F g−1 at 40 A g−1, respectively, much higher than that of the unmodified porous NiO film (261 F g−1 at 2 A g−1 and 191 F g−1 at 40 A g−1). The enhancement of pseudocapacitive properties is due to highly dispersed Ag nanoparticles in the composite film, which improves the electric conductivity of the film electrode.