Multi-functioning Supercapacitor Graphene Aerogel And Its Electric Field Sensing Mechanism

Compared with traditional batteries,the supercapacitors have attracted much attention due to their high power density,fast charge and discharge speed,and long-cycle stability.With the development of science and technology,the single function of energy storage is no longer meeting the requirement for supercapacitors,and research on multi-functional supercapacitors is inevitable for smart application.Among many supercapacitor electrodes,graphene aerogel has become a research hotspot to develop multi-performance supercapacitors,due to its features ultralight,high specific surface area,and high elasticity.The combination of conductive polymers and graphene aerogels can achieve their both advantages,thereby the multi-functions of self-repair,anti-vibration,and electric field sensing can be obtained for supercapacitor electrode,while ensuring the high energy density and long cycle life.The research of multi-functional graphene aerogel materials provides new ideas for expanding the application field of supercapacitors.Therefore,it is of great significance to study multi-functional graphene aerogels for coupling multiple properties on one electronic device.The specific research contents of this thesis are as follows:?1?A composite graphene aerogel?PrGOA-1?was prepared by a simple transfer method using the principle of self-assembly,and its preparation process,microstructure,and element distribution were analyzed.The composite graphene aerogel was prepared with a 490 nm thick zinc precursor and a mixed solution of Graphene oxide and Poly?3,4-ethylenedioxythiophene?:Poly?styrene sulfonate?with mass ratio of 1:1.The aerogel is ultra-thin with only 100?m thickness,and it has strong adsorption capacity.The graphene aerogel forms a two-dimensional film constisuted of three-dimensional porous composite structure.The two-dimensional graphene structure facilitates electron transport.The three-dimensional porous structure is beneficial to the contact area between the electrode material and the electrolyte,thereby the electrochemical performance of PrGOA-1 electrode was improved.?2?By constructing an experimental device,the multi-functional of PrGOA-1 and its coupling relationship were studied.The multi-function of graphene aerogel electrodes was tested by three electrode systems,water drop repair,cantilever vibration,and substrate replacement.The measured surface capacitance of the PrGOA-1 electrode was 190 mF cm^-2,and the capacitance retention rate was 98.7%after 10000 charge-discharge cycle tests.After the electrode is damaged,only 9 s is needed repair by the repair method with water droplet,and the electrochemical performance of the electrode remains unchanged after 8 damage/repair cycles.It is observed that the electrode stability is good after the electrode has been tested for 4000 vibrations.After changing the roughness and material and different conductive substrates,the electrochemical performance of the PrGOA-1 electrode remains unchanged,which shows the excellent machinability of the electrode.?3?Based on the symmetrical device structure,a solid-state electric field sensing device was prepared.This device can sensitively sense the electric field intensity in the range of1100 V m^-119000 V m^-1 and generate the corresponding response current.The distance between the electronic device and the electric field generator was changed to further investigate the relationship between the response current and the electric field strength,which showed a good linear relationship,indicating that the device can be used as an electric field sensor to sense the electric field strength.The finite element simulation method is used to study the working mechanism of the electric field sensing device.The simulation results reveal that the ion concentration in electrolyte inside the device change under different external electric fields,and different electric field intensities of simulated electric field sensing devices can be attributed to the increased active sites on the surface of graphene aerogels.By integrating amplifiers,power supplies,digital displays and other devices,a simple electric field sensing verification equipment is prepared.Under different electric field strengths,the device shows the corresponding indicator,which verifies the potential application of electric field sensing function.