Preparation And Performance Evaluation Of Flexible Supercapacitors

With the rapid development of wearable smart electronic energy storage devices,research on flexible supercapacitors as electric energy sources has become more and more important.For self-healing and stretchable flexible supercapacitors,the self-repairing ability is particularly important for restoring the mechanical integrity and electrochemical performance of the flexible supercapacitor when it is deformed or stretched.At the same time,superhydrophobicity has attracted strong attention from the scientific community due to its excellent properties such as self-cleaning.Therefore,the integration of self-healing,super-hydrophobic multi-function into energy storage devices will provide a new idea for the research of energy storage devices.Therefore,this paper designed an ingenious preparation method and successfully constructed a self-repairing,super-hydrophobic integrated flexible supercapacitor.The specific research is as follows:（1）According to the superhydrophobic theory,the superhydrophobic phenomenon in nature is analyzed,and from this phenomenon,it is concluded that in order to obtain a superhydrophobic surface,it is essential to construct a certain degree of surface microstructure.In order to avoid the displacement and delamination during the deformation of the assembled multilayer structure,as well as the influence of hydrogel swelling and dehydration,the flexible supercapacitor has controllable surface wettability and hydrophobicity.Therefore,this paper combines the flexible supercapacitor with the supercapacitor.The hydrophobic coating technology is combined to prepare a super-hydrophobic,self-repairing integrated flexible supercapacitor.With PVA/HNO₃ hydrogel as the electrolyte material,self-healing ability can be realized without freezing/thawing process.Graphene and carbon nanotubes are used as electrode materials,and after surface modification,a hydrophobic suspension composed of graphene and multi-walled carbon nanotubes is sprayed onto both sides of the hydrogel electrolyte to construct superhydrophobic electrodes.This idea of preparing electrodes and capacitors paves the way for further research on flexible energy storage devices.（2）This paper studies the application of nickel-cobalt-carbon synergy in superhydrophobic flexible supercapacitors.The binder-free carbon-nickel-cobalt electrode also exhibits excellent capacitance performance,and the assembled flexible supercapacitor exhibits excellent self-repair capability and cycle stability.The elongation at break of the solid hydrogel is 400%at the highest stress of 1870KPa.Reflects the excellent stretch rate of flexible supercapacitors.After 2000 cycles at room temperature,the capacitance reached a capacitance retention rate of 75.4%.After 2000cycles in water,the capacitance retention rate reached 72.4%,which fully reflects the excellent superhydrophobic ability and stable electrical Chemical properties.After 20cycles of interruption/repair process,the specific capacitance retention rate can still be maintained at 85.3%,reflecting the excellent self-repairing ability.These advantages make flexible supercapacitors have broad application prospects in the field of flexible electronic devices.Therefore,superhydrophobic flexible supercapacitors can be used as the next generation of superhydrophobic flexible self-repairing electrochemical energy storage devices.