Preparation And Research Of Graphene Based Aqueous Fiber Supercapacitor

With the rapid development of portable wearable electronic devices,flexible energy storage devices,especially fiber supercapacitors,have unique advantages in power density and mechanical properties,and have broad application prospects in the field of flexible electronics.According to the formula E=1/2CU²,under certain voltage conditions,high specific capacity plays a key role in the energy density of fiber supercapacitors.Therefore,research on fiber electrodes with high specific capacitance,high mass transfer characteristics and excellent mechanical properties is important for the development of fiber supercapacitors.Fiber supercapacitors with high energy density and high power density have important scientific significance.Graphene（rGO）has the advantages of large specific surface area,high electrical conductivity,high chemical stability and high tensile strength（130GPa）,which meets the requirements for the preparation of fiber supercapacitors.This article studies the preparation of fiber supercapacitors.The main contents and results are as follows:（1）Preparation and research of fiber supercapacitors based on rGO.The film twisting method,which is different from the traditional wet spinning or dry spinning,is used to study the influence of different precursors,reduction methods and electrolyte concentration on rGO fiber supercapacitors.Studies have shown that the graphene oxide（GO）fiber prepared from the 32 mesh graphite precursor has good mechanical properties.After HI chemical reduction,it is matched with 3 M H₂SO₄ electrolyte,showing a volume specific capacitance of 29.8 F cm^-3,and the measured The maximum breaking strength of the fiber can reach 36 MPa,and the breaking elongation is 7.5%.（2）Preparation and research of fiber supercapacitors based on PEDOT:PSS/rGO.By adjusting the content of PEDOT:PSS and using the film twisting method,the effect of the content of PEDOT:PSS on the capacity,rate performance and mechanical properties of the composite fiber supercapacitor was studied.Studies have shown that the addition of conductive polymer PEDOT:PSS can prevent the re-stacking of rGO sheets,and its good pseudocapacitance properties and mechanical properties provide additional specific capacitance and flexibility.When the content of PEDOT:PSS is 20wt.%,it has good rate performance.It has a volume-to-volume capacitance of135 F cm^-3 at a scanning speed of 2 m V s^-1.At this time,the capacity is 4.5times that of a pure rGO fiber supercapacitor.The capacity retention rate of10,000 cycles is 81.8%,and the maximum breaking strength of the fiber can reach 33.3 MPa,and the breaking elongation rate is 7.5%.（3）Preparation and research of fiber supercapacitors based on MXene/rGO.By adjusting the content of MXene and using the film twisting method,the effect of the content of MXene on the capacity,rate performance and mechanical properties of the composite fiber supercapacitor was studied.Studies have shown that the addition of MXene can break the capacity limit of PEDOT:PSS/rGO composite fiber electrode.When the MXene content reaches24 wt.%,the capacity is as high as 275 F cm^-3,which is 9 times that of pure rGO fiber,and it can still maintain 94%of the capacity after 10000 cycles.When the all-solid fiber supercapacitor assembled with PVA-H₂SO₄ gel as the electrolyte is bent at an angle of 180°,the electrochemical performance does not significantly decrease,and the maximum breaking strength of the fiber is21.9 MPa,and the corresponding maximum elongation is 2.7%.