The Preparation And Properties Of Three-Dimensional Nanoporous Gold Based Electrodes For Flexible Au-Solid-State Supercapacitors

With the continuous development of social economy and science and technology,energy and environmental issues have become issues that must be faced in the development of human society.As a new type of environmentally friendly energy storage equipment,supercapacitors have a greater energy density than traditional capacitors and a higher power density than batteries,which has huge market potential in the energy field.For supercapacitors,the electrode material is the key to determine its performance.Therefore,finding a high-performance electrode material has become a hot research topic.Among them,polypyrrole(PPy)has received wide attention for its easy synthesis,good performance,low price,and environmental friendliness.However,due to its poor cycle performance and low electrical conductivity,polypyrrole has been shackled in practical applications.Therefore,it may be considered to select a suitable material and polypyrrole compound,so as to improve its conductivity and stability.Nanoporous gold(NPG),as a new type of nanomaterial,has a unique three-dimensional nano-continuous pore structure.At the same time,it has high electrical conductivity,large specific surface area and good stability.It is the best choice for electrode material collectors.In this thesis,NPG is used as the current collector,graphene oxide(r GO)and PPy or carbon quantum dots(CQDs)and PPy are used as the active materials.At the same time,the prepared composite material is assembled into an all-solid flexible supercapacitor,and its electrochemical performance is studied.The main research contents are as follows:(1)Electrochemical polymerization method was used to electrochemically deposit the reduced r GO and PPy onto NPG,and the graphene oxide-polypyrrole/nanoporous gold(r GO-PPy/NPG)composite electrode material was prepared.Scanning electron microscopy(SEM)and transmission electron microscopy(TEM)analysis of the microscopic morphology shows that the composite active material is deposited along the NPG skeleton,forming a three-dimensional interconnected porous network structure.Using electrochemical workstation,the electrochemical performance of r GO-PPy/NPG composite electrode material was studied by cyclic voltammetry,constant current charge and discharge and AC impedance spectroscopy.The results showed that when the current density was 0.25 m A/cm~2,r GO-PPy/NPG composite electrode material can have an area specific capacitance of 215m F/cm~2,an energy density of 238.8 m Wh/cm~3,and a power density of 2.2W/cm~3;r GO-PPy/NPG composite electrode material passes through at a scan rate of 100 m V/s after 2000 cycles of testing,it can still maintain 91%of the maximum capacitance.(2)Carbon quantum dots(CQDs)were prepared by hydrothermal method,and a mixed solution of CQDs and PPy was electrochemically deposited on NPG as substrate,and carbon quantum dots-polypyrrole/nanoporous gold(CQDs-PPy/NPG)with different deposition times were prepared composite electrode material,and tested and compared its performance.The results show that the composite electrode material has the best performance when the deposition time is 10 minutes.By characterizing the microscopic morphology of the material,it can be seen that the material is a double-layer nanoporous structure.The electrochemical performance of the material was tested using an electrochemical workstation.The results show that when the current density is 1A/g,the mass specific capacitance of the CQDs-PPy/NPG composite electrode material can be up to 755 F/g,and the energy density is 108.8 Wh/kg,power density is 10 k W/kg;under the condition of sweep speed of 100 m V/s,CQDs-PPy/NPG composite electrode material can still maintain 90.5%of the maximum capacitance after 5000 cycles.