Pseudocapacitive properties of electrodeposited porous nanowall Co3O4 film

Abstract A porous nanowall Co 3 O 4 film is prepared by a facile cathodic electrodeposition. The as-prepared porous nanowall Co 3 O 4 film shows a net-like porous structure with huge porosity. The porous network is made up of free standing interconnected Co 3 O 4 nanoflakes with a thickness of 20 nm. As cathode material for pseudocapacitors, porous nanowall Co 3 O 4 film exhibits weaker polarization, higher electrochemical reactivity and better cycling performance as compared to the dense Co 3 O 4 film. The specific capacitance of porous nanowall Co 3 O 4 film is 325 F g −1 at 2 A g −1 and 247 F g −1 at 40 A g −1 , respectively, much higher than that of the dense Co 3 O 4 film (230 F g −1 at 2 A g −1 and 167 F g −1 at 40 A g −1 ). The better pseudocapacitive performances of the porous nanowall Co 3 O 4 film are attributed to its highly porous morphology, which provides large reaction surface and short ion diffusion paths, and relaxes the volume change caused by the reaction during the cycling process.