Research On Planar On-chip Micro-supercapacitors Based On Graphene Oxide By Two-step Reduction

The rapid development of portable electronic devices has greatly stimulated the demand of today’s society for electrochemical energy storage devices that have both miniaturization and high energy density and power density.Planar On-chip Micro-supercapacitors have good power and energy storage characteristics at the same time,which can satisfy microelectronic devices for high charging and discharging speeds and high energy storage.Therefore,it is becoming a new frontier research direction in the field of energy storage device research.Based on the self-assembly method of graphene oxide thin film produced by the gas-liquid interface,this paper prepared two methods by two-step reduction method,namely,continuous operation of normal temperature hydroiodic acid reduction and high temperature thermal annealing reduction.Two-step Reduced Graphene Oxide film.AFM,XPS,XRD and four-probe results show that the film is very thin,only about 3 nm,and the carbon-to-oxygen atomic ratio of the film reaches 34.84,and the reduction peak position and interlayer distance are 26.2°and3.39?,respectively.The film was reduced very effectively,and finally the film obtained high conductivity of 2037.5 S cm^-1.In this paper,a miniature supercapacitor based on a two-step reduction graphene oxide planar sheet was prepared.For the first time,the width of the interdigitated electrode and the gap distance were reduced to the order of 100（both8μm）based on the photolithography method.The test results show that the device has very good rate performance,the scan rate can range from 0.01 V s^-1 to 10000 V s^-1,and the cyclic voltammetry curve has always been more standard during the change from low to high sweep speed.Rectangle.At an ultra-high sweep speed of10,000 V s^-1,the device power density is 12.18 W cm^-3,the energy density at 0.01 V s^-1 is 40.97 m Wh cm^-3,and the volume capacitor is as high as 294.97 F cm^-3.The response time constantτ0 is as low as 2.16μs.In addition,the planar on-chip miniature supercapacitors have good cycle stability.At a high sweep speed of 5000V s^-1,the capacitance retention rate after 10,000 cycles is as high as 97.3%.In order to further explore the effects of specific surface area and ion transmission distance on device performance,three planar micro supercapacitors（referred to as wide gaps of 8μm,40μm,and 200μm,respectively）were designed and prepared,and their electrochemical performances were investigated.test.The results show that with the reduction of the magnitude of the width,the ion transmission distance is shortened,and the relative surface area has been greatly improved,which has greatly improved the performance of all aspects of the supercapacitor,especially the energy has finally been achieved The simultaneous increase of density and power density proves that it is very meaningful to continue to reduce the finger and gap width,and to increase the amount of interpolation index at the same time.