Design And Preparation Of Stretchable Self-healing Conductive Hydrogels For Energy Storage Devices

Emerging wearable electronic devices have a broad application prospect in the fields of human-computer interaction,artificial intelligence and health monitoring systems due to their good compatibility with human organs and excellent self-healing ability after damage.To meet the demands of future wearable electronic devices,it is critical to develop stretchable self-healing supercapacitors（SCs）.Current SCs mainly achieve stretchability through structural design.The complicated process and the wavy structure are not conducive to the integration of subsequent wearable devices.In addition,they commonly exhibit no self-healing ability or suffer limited self-healing efficiency.To solve the above problems,it is essential to exploring novel electrode and electrolyte materials.In this context,we took conductive hydrogels（CHs）as the research object and developed highly stretchable and self-healing CHs-based electrodes and electrolyte materials through multiple non-dynamic covalent bond interactions.Using the resultant CHs-based electrodes and electrolyte materials,high-performance SCs were then constructed.As the electrodes and electrolyte possessed excellent mechanical stretchability and self-healing ability,the subsequent assembled SCs also exhibited comparatively high stretchability and self-healing capability,which laid a foundation for the development of future flexible wearable electronics.The main contents of this dissertation are as follows:（1）A stretchable self-healing PAA-DMAPS-Fe³⁺hydrogel electrolyte was prepared by covalent cross-linking and dynamic non-covalent bonding.The as-prepared hydrogel electrolyte could not only endure tensile strain of 2095%and quickly self-heal at room temperature but also demonstrate excellent electrical conductivity.Based on the developed hydrogel electrolyte,an all-in-one supercapacitor was constructed,which required no additional substrate material,thus simplifying the assembly procedure and reducing the cost.In addition,the interlocking structure between the electrode and electrolyte of the SC,on the one hand,decreased the interfacial resistance and improved the areal specific capacitance(up to 109 m F cm^-2);on the other hand,enhanced the mechanical flexibility and stability.Under bending and twisting state,the areal specific capacitance of the SC could still reach 97 m F cm^-2 and 94 m F cm^-2,respectively.More importantly,the SC also showed superior intrinsic stretchability and moderate self-repair ability.The SCs based on the stretchable self-healing electrolytes provide feasible technical proposal for the development of high-performance energy storage devices for flexible wearable electronics.（2）By introducing stretchable self-healing hydrogel skeleton into the conductive phase of PEDOT:PSS,the synergistic regulation of mechanical stretchability,self-healing ability and electrical conductivity of PEDOT:PSS hydrogel was realized,and a conductive hydrogel electrode material with excellent comprehensive performance was developed.The maximum tensile strain of the hydrogel electrode was as high as 1086%,which still maintained 628%after self-healing from fracture,indicating superior self-healing capability.Besides,the electrical conductivity could reach2.5 S m^-1.The excellent comprehensive properties are among the best.Furthermore,wearable supercapacitors and flexible sensors were constructed based on the developed conductive PEDOT:PSS hydrogel.The excellent comprehensive performance of the conductive polymer hydrogel electrode enables it to be widely used in the fields of wearable supercapacitors,implantable sensors,electronic skin,etc.,which lays a foundation for the development of flexible wearable electronics.