Research On Flexible Supercapacitors Based On Redox Active Double Network Hydrogel Electrolyte

Excellent electrochemical and mechanical properties are the basic standards for the application of flexible supercapacitors in wearable electronic products.However,at present,the toughness and energy density of flexible supercapacitors are still low,which fundamentally restricts the development of wearable electronic products.Electrolytes are an important factor in determining the performance of supercapacitors.In recent years,because the water gel is rich in big hole structure,and has excellent mechanical properties such as high strength,good flexibility,many researchers have applied to the super capacitor,was prepared in toughness and high energy density of super capacitor at the same time,also solved the problem of easy in liquid electrolyte leakage,poor security problems,has received the widespread attention.In this paper,the dual-network hydrogels were firstly prepared and applied to flexible supercapacitors to study their electrochemical properties.Then,electroactive substances were introduced into the hydrogels to increase their capacitive storage capacity through REDOX reaction,and applied to flexible supercapacitors:?1?With ammonium persulfate as initiator,N,N'-methylene double acrylamide as crosslinking agent,and adding or sodium alginate and chitosan were prepared based on two kinds of polyacrylamide hydrogel double network,was studied by SEM,FTIR,two kinds of channel and chemical structure of the hydrogel,based on mechanics performance index,compares the two kinds of the performance of the hydrogel,in which sodium alginate/elongation at break of polyacrylamide hydrogel can reach 1500%,fracture strength of 265 KPa;Choose sodium alginate/polyacrylamide hydrogel microspheres,by soaking KCl electrolyte solution,water gel electrolyte was prepared,based on this,as the electrode with carbon paper,the preparation of the sandwich structure of flexible super capacitor,the cyclic voltammograms,constant current charge-discharge and ac impedance spectroscopy studies the performance of super capacitor,under the current density of 1 m A/cm²,the area of the super capacitor specific capacitance can be to 15.1 m F cm^-2,and under the dynamic forces,has the stable power output.?2?By REDOX active electrolyte enhanced supercapacitor energy density,soaked the hydrogel in containing KCl,iron ion,and in a solution of catechol,optimize the iron ion and the ratio of catechol,on the basis of maintaining mechanical properties of the hydrogel,Faraday reactivity,give water gel by SEM,FTIR,UV-Vis,electrochemical test and DFT theory simulation,discusses the REDOX active water gel electrolytes involved in energy storage reaction mechanism.On this basis,the paper as the electrode and carbon,assemble the sandwich structure of flexible super capacitor,electrochemical tests show that the super capacitor is as the nature of the electric double layer capacitor and battery hybrid supercapacitors,under the current density of 1 m A/cm²,the area of the super capacitor specific capacitance can be to189.1 m F cm^-2,the energy density of 32.71?Wh cm^-2,increased 11.5 times and 5times respectively,after the 5000 times charging and discharging cycle,capacitance,no obvious attenuation show excellent cycle stability.Under the action of a series of dynamic external forces including compression,torsion,hammering and cutting,the specific capacitance retention rate of the capacitor is above 95%,indicating that the whole supercapacitor has excellent flexibility.