Preparation Of Polyaniline Conductive Hydrogel And Its Application In Flexible Electrodes

Flexible supercapacitors have broad application prospects in portable and wearable electronics（such as curved,smart watches,laptops and electronic skins）due to their good electrochemical properties（high power density,high charge-discharge rate,wide operating temperature range,low maintenance consumption,long cycle life）and excellent mechanical properties.As an important component of supercapacitors,flexible electrodes affect the performance of flexible supercapacitors.The traditional strategy for preparing flexible electrodes is to prepare fiber-supported paper-like supported flexible electrodes（such as transferring or covering electrochemically active materials on elastic rubber fibers,cotton cloth,etc.）,but it is difficult to withstand large deformations,and the preparation process is complicated and difficult to scale application.This paper focuses on the problem that most flexible electrodes cannot withstand large deformation at present,by preparing a three-dimensional network structure hydrogel electrode,the electrode has good electrochemical performance and excellent mechanical properties,so that the flexible electrode can be better used in flexible electronics and in wearable devices.It mainly includes the following aspects:（1）Polyacrylamide is used as a flexible substrate,and graphene oxide is added to improve the electrochemical performance of the electrode,and the second is to stabilize the conductive material polyaniline,so that it has better electrochemical performance.Sodium is used to disperse graphene oxide and improve mechanical properties.A two-step method was used to prepare polyacrylamide-graphene oxide-polyaniline composite hydrogel electrodes.The electrochemical properties of the electrodes were tested by cyclic voltammetry,galvanostatic charge-discharge method and electrochemical impedance method.The effect of different graphene oxide content on the capacitance was investigated.Experiments show that the area specific capacitance of PGPH₃ can reach 100.57 m F cm^-2 at 5 m A cm^-2,and PGPH₃ has good cycling stability.After 1000 cycles of GCD at 5 m A cm^-2,it still maintains the initial capacitance.75.54%,which proves that the combined action of graphene oxide and polyaniline can effectively improve the electrochemical performance of the electrode.In addition,PGPH₃ also has good mechanical properties with an elongation at break of 352%.In addition,the prepared hydrogel can monitor a wide range of joint activities and subtle muscle activities,so it also has good application prospects in flexible sensors.（2）Porous flexible substrates were prepared with STD as pore-forming agent,PA as dopant and cross-linking agent,and aniline was polymerized into polyaniline by in-situ polymerization to form PASH flexible electrodes,which were electrochemically tested.The effects of pore-forming agent content and the number of freezing cycles on the electrochemical performance were investigated.The experiment was prepared by the freezing cycle method,and the crystallization and extrusion during freezing process can make the hydrogel form a network structure.Phytic acid can interact with polyaniline to cross-link polyaniline.STD can be used as a pore-forming agent to increase growth sites for polyaniline.Increasing the number of freezing cycles can make the pore size more obvious,thereby improving the electrochemical performance.Experiments show that when the STD content is 15w%and the number of freezing cycles is 2,the specific capacitance reaches a maximum of 501.34 m F cm^-2(1 m A cm^-2),and 77.3%of the initial capacitance is maintained after 1000 GCD cycles,indicating a good cycle.stability.At the same time,the mechanical properties are excellent,the elongation at break reaches 815%,and the tensile strength reaches 0.61 MPa,which can lift the 100 g weights without damaging itself.This illustrates its potential and broad application prospects in flexible sensor.