Preparation And Properties Of Polymer Based Hydrogels For Supercapacitors

In recent years,with the increasing pursuit of portable,thin,and intelligent electronic products,the research interest in flexible supercapacitors has continued to increase.Providing more flexible,thinner,and more stable physical materials is an indispensable requirement for the development of diversified flexible supercapacitors.Hydrogel polyelectrolyte is a kind of green,pollution-free and low-cost electrolyte,whose form is between solid and liquid electrolyte.It has higher ionic conductivity than pure solid electrolyte and higher safety performance than liquid electrolyte.Therefore,we select hydrogel polyelectrolyte as the research object in this research,and prepare the electrolyte with high ion conductivity by formulating a reasonable production formula.The specific research contents are as follows:（1）Using 2-acrylamido-2-methylpropanesulfonic acid（AMPS）and hydroxyethyl methacrylate（HEMA）as monomers,PAMPS/PHEMA hydrogel polyelectrolytes are prepared by copolymerization.Subsequently,a series of electrochemical performance tests has been carried out on the supercapacitor assembled by this electrolyte.The results show that the excellent network structure and unique hydrogel properties of electrolyte could provide a reliable support for ion transport and migration,and the excellent performance is no less than that of the water electrolyte.Among them,the electrochemical performance of H₂SO₄ electrolyte is the best,the mass ratio capacitance of device has reached 139.8 F/g at 0.1 A/g.（2）In order to further improve the ionic conductivity of hydrogel electrolyte,PEDOT has been introduced into the PAMPS/PHEMA hydrogel polyelectrolyte system by in-situ polymerization.Afterwards,the electrochemical performance of the supercapacitor assembled by PAMPS/PHEMA/PEDOT has been tested.The capacitance of the supercapacitor could reach 140.5 F/g at 5 mv/s,which is 88.8%higher than the PAMPS/PHEMA hydrogel polyelectrolyte.These results tell that PEDOT has been doped to PAMPS/PHEMA by in-situ polymerization can effectively optimize the electrochemical performance of hydrogel polyelectrolyte.（3）In order to explore the application value of electrolyte in flexible supercapacitors,flexible supercapacitors are assembled with PAMPS/PHEMA/PEDOT hydrogel as electrolyte,nickel foam as current collector,activated carbon as active material,and their electrochemical stability tests are conducted.The results show that the flexible device can maintain the electrochemical performance of 84.5%and 74.4%in the normal state under the deformation of 90°and 180°,indicating that the gel electrolyte has good bending resistance and folding resistance.In addition,the widening voltage window test and destructive test are carried out on the flexible supercapacitor.The voltage window can reach 2 V,and the output voltage can be basically kept unchanged after cutting.The experimental results show that the flexible supercapacitor energy storage device assembled with the gel electrolyte has certain practical application prospects.