Research Of Planar On-chip Micro-Supercapacitors Based On Reduced Graphene Oxide

Electronic products are becoming lighter,thinner and smaller,resulting in a huge demand for energy storage.As a new energy storage device,planar micro-supercapacitor?MSCs?has high performance,and it can integrate with micro-nano devices to provide effective charge energy.Graphene oxide?GO?films with different parameters?spin-coating rates and layers?were prepared by spin-coating method.Reduced Graphene Oxide?RGO?films were prepared by HI reduction.The results of AFM,XPS,XRD and four-probe measurements show that the prepared RGO film is 6 nm,has high conductivity(649.77 S cm^-1),and C/O ratio is 8.02 when the spin coating?one layer?rate(2500 r min^-1)is high.RGO-MSCs with different electrode widths were fabricated by the process of lithography and etching,and electrochemical performance was tested.The results show that the specific surface area increases with the narrowing of the ratio of finger width to gap and the narrowing of the equal ratio,thus the transmission speed of electrons and ions are increased.With the decrease of the ratio of finger width to gap or the narrowing of equal ratio,the time constant decreases obviously,but due to the partial breakage of the interdigital structure during the preparation of the interdigital electrode,the longer ion transport path in the gel electrolyte may lead to greater equivalent resistance.After 10000 cycles,the capacitance of RGO-MSCs with different finger width and gap ratio kept above 92.81%,while that of RGO-MSCs with constant ratio narrowing was kept above 84.67%.RGO-MSCs with serial/parallel configurations and corresponding single cell were fabricated by the process photolithography and etching,and electrochemical performance was tested.The results show that all the configurations keep nearly symmetrical rectangular shape and instantaneous response when the voltage reversal occurs,forming an effective double layer with good charge transfer between the two electrodes,and having a small capacitive behavior of Faraday reaction.The MSCs with designed series configuration have better electrochemical performance than the MSCs with series single cell,and its working potential is twice that of MSCs with series single cell.The designed parallel structure may result in the capacitance of the MSCs with parallel configuration being more than two times higher than that of the MSCs with single parallel cell.At the scanning rate of 10 V s^-1,the capacitance of MSCs with all configurations remained above 94.2%after 10000 cycles.