Electrophoretic Deposition Of Hierarchical Micro/Nanostructure Composite Electrodes Based On Carbon Fiber

In this paper,carbon nanotubes(CNT)/carbon nanofibers(CNF)/carbon fibers(CF)composite electrodes as well as nickel oxide(NiO)/carbon nanotubes(CNT)/carbon nanofibers(CNF)/nickel foam composite electrodes were prepared via electrophoretic deposition.Preparation conditions,surface morphology and electrochemical properties of the electrodes were studied.Carbon nanotubes were firstly purified by mixed acid to form a uniform dispersion state in ethanol.Carbon nanofibers were treated in the same way,followed with an addition of metal salt ions in convenient for electrophoretic deposition.Carbon fibers were desized by soxhlet extraction,which removed the sizing agent and increased the electrical conductivity of carbon fibers.SEM and electrochemical analysis indicated that the optimal conditions to prepare CNT/CF electrodes were 20 V/5 min.Then we introduced carbon nanofibers to prepare CNT/CNF/CF composite electrodes.SEM showed a scaffold-structure of the nanofibers in the surface of carbon fibers,which increased the surface area of deposited carbon nanotubes and led to an enhancement of the specific capacitance.Electrochemical measurements revealed that the maximum specific capacitance of CNT/CNF/CF electrodes reached up to 176.4 F·g-1,which increased 114%compared with CNT/CF electrodes.We further prepared NiO/CNT/nickel foam electrodes via electrophoretic deposition.By introducing CNF before CNT deposition,we prepared NiO/CNT/CNF/nickel foam electrodes with a hierarchical structure.SEM&TEM measurements showed that CNT formed a porous network on the electrodes,and CNF could further increase the surface area of the network.The final NiO/CNT/CNF/nickel foam electrodes exhibited the highest specific capacitance of 1372.0 F g-1 at 5 A·g-1,which increased 27.4%compared with NiO/CNT/nickel foam electrodes.