Electric Field Assisted Reduction Of Graphene Oxide Film And Its Electrochemical Performances

Graphene itself has outstanding electrical,optical,mechanical and thermal properties,and has a wide range of applications in the fields of energy,electronic devices,catalysis and batteries.The preparation of large-scale,low-cost,and high-quality graphene materials is a key prerequisite for realizing its application.The graphene oxide（GO）reduction method effectively restores its electronic structure and removes oxygen-containing groups by reducing GO.It has the advantages of low-cost,convenient operation and simple process.It is recognized as one of the most potential methods for large-scale production of reduced graphene oxide（r GO）.Traditional GO reduction mainly includes thermal reduction and chemical reduction.The former requires a high temperature above 1000°C and an inert environment,and the cost of reduction is relatively high;the latter requires the help of various chemical reducing agents,which have the disadvantages of being highly toxic and unfriendly to the environment..Therefore,it is of great significance to explore a simple,efficient,low-cost and environmentally friendly reduction GO method for the application of r GO.In this paper,we proposed a new method of GO reduction method-electric field assisted reduction,through the electric field assisted reduction of the GO film to obtain the r GO film,and the influence factors such as voltage,current and reduction time in the process of reduction were studied;secondly,GO was composited with nano-TiO₂ and Mo S₂ nanosheets by ultrasonic composite method,and the TiO₂/r GO composite film and Mo S₂/r GO composite film were obtained after electric field assisted reduction.At the same time,the phase structure,microscopic morphology and element composition of the composite film were characterized,and its electrochemical performance was tested.The main findings are as following:A stable GO dispersion was prepared by ultrasonic dispersion of graphite oxide,and a GO film was obtained by vacuum filtration,and then an electric field assisted reduction was performed on it under N₂ conditions to obtain an r GO film.The sheet resistance of the film was characterized by the four-probe method,the influence of different reduction process parameters on the r GO film was discussed,and the samples were characterized by XRD,SEM,XPS,and Raman.The study confirmed that GO was successfully reduced to r GO through an electric field assisted reduction,and part of the functional groups on the lamellae were successfully removed.The optimal reduction process parameters were determined to be:reduction voltage of 50 V,current limit value of 250 m A,and current limit duration of 30 s.The electrochemical performance of the r GO film was tested,and the results showed that the specific capacitance of the reduced r GO film under the conditions of 1 A g^-1 current density under the optimal process parameters was 101 F g^-1,which was compared with the r GO film without an electric field(The specific capacitance value was 43 F g^-1),the performance was greatly improved.Nano-TiO₂ dispersion was prepared by ball milling technique,then,the TiO₂/GO composite film was obtained by ultrasonic composite method and GO dispersion solution,finally,the TiO₂/r GO composite film was obtained by electric field assisted reduction method.The structure and morphology of the TiO₂/r GO composite film were analyzed,and the impact of different TiO₂ composite amounts on the electrochemical performance of the TiO₂/r GO film samples was further discussed.The results showed that the TiO₂/r GO composite film was successfully prepared by the electric field assisted reduction,and the nano-TiO₂was uniformly dispersed between the layers of the r GO film.The electrochemical performance of TiO₂/r GO composite film was tested.The results showed that when the composite volume of nano-TiO₂was 2 m L,the specific capacitance of the composite film was 155 F g^-1,and the specific capacitance of the composite film kept 83.6%of the initial capacitance after 1000 cycles of charge and discharge under the condition of current density of 5 A g^-1.The MoS₂ nanosheet dispersion was successfully prepared by ball milling,then ultrasonic and centrifugation,and then composited with GO by ultrasonic,Mo S₂/GO composite films were prepared by vacuum filtration,and finally Mo S₂/r GO composite films were obtained by electric field assisted reduction method.Mo S₂/r GO composite film.XRD,SEM,XPS and other analyses were performed on the Mo S₂/r GO composite films prepared under different Mo S₂nanosheet composite amounts,and their electrochemical properties were further discussed.The results showed that the Mo S₂/GO composite film was successfully reduced by electric field assisted reduction to obtain the Mo S₂/r GO composite film,and the addition of Mo S₂ nanosheets acted as a"separator"to avoid the close stacking of r GO.Through the analysis and discussion of the electrochemical performance of Mo S₂/r GO composite films prepared under different Mo S₂ nanosheet composite amounts,the results showed that when the composite volume of Mo S₂ nanosheets was 3 m L,the specific capacitance of the obtained Mo S₂/r GO composite film reached 144.5 F g^-1,and the specific capacitance was 86.4%of the initial capacitance after 1000cycles of charge and discharge under the condition of current density of 5 A g^-1.