Research On Performances Of Planar On-chip Micro-supercapacitors Based On Graphene Quantum Dots

At present,with the popularity of small electronic products and the increase in demand,the requirements for energy storage systems are also increasing,and the demand for new energy storage systems is also increasing.Among the energy storage system,planar on-chip micro-supercapacitors have many excellent characteristics,such as:shorter example transmission paths,larger specific capacitances,good security,and so on.As an important component of capacitors,electrode materials determine the performance of planar micro supercapacitors to a large extent.Graphene quantum dots?GQDs?are an ideal electrode material due to their advantages such as nanometer size,abundant edge defects,good electrical conductivity,high mobility,good chemical stability,and ease of functionalization.In this paper,nitrogen-oxygen co-doped graphene quantum dots films were prepared by modified liquid-air interface self-assembly method,planar on-chip micro-supercapacitors were prepared using GQDs films as electrodes.In this paper,2 mg/ml GQDs were used as electrode raw materials to prepare electrode films via modified liquid-air interface self-assembly.Then the electrode film was tested by atomic force microscope,X-ray photoelectron spectroscopy,Raman spectroscopy and Transmission Electron Microscope.The average particle size of the GQDs is 7.4 nm,the atomic ratio of carbon,oxygen,and nitrogen in the GQDs film with a thickness of 12 nm was 4.3:2.9:2.8.In this paper,planar on-chip micro-supercapacitors were prepared using GQDs thin electrode films and its electrochemical performance was calculated after the cyclic voltammetry test.For the cyclic voltammetry?CV?curve test of micro-supercapacitors,the scan rate range is 0.1 V s^-1to 10,000 V s^-1,the area capacitance and stack capacitance of the device were 4.1355?F cm^-2and 3.4463 F cm^-3at 0.1 V s^-1,and the energy density was 478.6458?Wh cm^-3.At a scan rate of10,000 V s^-1,the power density of the device is 43.6127 W cm^-3.The cycling stability of the device remained 98%after 10,000 cycles at a scan rate of 10,000 V s^-1.The electrochemical performance of GQDs-based on-chip micro-supercapacitors?GQDs-MSCs?was compared with the reduced graphene oxide-based on-chip micro-supercapacitors?RGO-MSCs?,both of them was prepared with the same preparation method and specifications,shows that GQDs-based planar supercapacitors have better electrochemical performance at high scan rates.The experiments in this paper show that the GQDs-MSCs prepared by modified liquid-air interface self-assembly have good application prospects.