Research Of Preparation Of Self-Assembled Graphene-Based Capacitors Based On Laser Etching Superhydrophobic/Hydrophilic Composite Surface

The performance of graphene based planar interdigital electrode is excellent,but the preparation method is complex,so it is very important to develop a technology of rapid preparation of graphene based planar interdigital electrode for the development of micro capacitor.In this paper,the composite interdigital patterns of superhydrophobic（SH）and superhydrophilic（SHL）were fabricated on the surface of rigid and flexible substrates by laser direct writing patterning technology.The interdigital patterns of graphene ink were controlled by controlling the structural changes of different wettability surfaces.A kind of planar micro capacitor was prepared,and the electrochemical performance of the micro device was tested through the electrochemical workstation.The main research work includes:A superhydrophobic/superhydrophilic composite surface was prepared by using infrared nanosecond laser surface etching and stearic acid solution modification on alumina substrate.The rigid all solid state planar micro capacitor assembly was obtained by coating aqueous graphene solution and solid polyvinyl alcohol sulfuric acid gel electrolyte.The test results show that the area specific capacitance of the micro super capacitor with rigid substrate can reach 5.5 m Fcm^-2 at the voltage scanning rate of 5 m V s^-1,and has a good capacitance retention rate of～88.5%after 4500 cycles.The superhydrophobic and superhydrophilic mixed surfaces were obtained by picosecond laser etching for polyimide flexible films.The flexible solid state capacitors were obtained by coating aqueous graphene solution and solid polyvinyl alcohol sulfuric acid gel electrolyte.The test results show that the area specific capacitance of the micro super capacitor on the flexible substrate can reach 7.67 m Fcm^-2 at the voltage scanning rate of 5 m V s^-1,which is better than the performance of the micro capacitor on the rigid substrate.After 5000 cycles,the capacitor retention rate is～90.1%,which shows better cycle stability than the micro capacitor on the rigid substrate.The research results in this paper show the advantages of laser rapid preparation of planar micro capacitors with ultra-fine interdigital electrodes.This kind of graphene based micro capacitor can be used for micro/nano scale power supply,and can also be used to integrate many small electronic devices,which has great potential in the field of on-chip systems.