Study On Preparation And Performance Of Aramid Fiber Elastic Capacitors

Flexible/wearable portable electronic products are the development direction of electronic components in the future.Among them,the flexible capacitor,as the most basic electronic device,is the cornerstone of flexible electronic products.Therefore,it is very important to develop flexible electrochemical capacitors with excellent mechanical and electrochemical properties.This paper aims to develop a flexible aramid fiber-based elastic capacitor with high mechanical properties and stable electrochemical performance.With the technical goals of high elasticity,high tensile strength and light weight,three aramid fiber-based elastic capacitors with different woven structures were designed:KF/Ag-TE-KF/Ag,KF/Ag-FE-KF/Ag,KF/Ag-KF-KF/Ag structure.Through mechanical performance test,elastic performance test and liquid absorption test,it is found that the tensile strength of the KF/Ag-KF-KF/Ag elastic capacitor rope structure is 114.8 N,and the specific strength is 1.849×10⁴ N·m·kg^-1,although The mechanical properties are less than the other two structures,but it has good elasticity,light weight,strong liquid absorption capacity,and strong deformation ability,which can meet the 75%deformation requirements of human body movement.KOH/PVA and C₈H₂₁NO/PVA gel electrolytes were prepared,and their morphology and structure were characterized by SEM,FT-IR,and Raman,and the environmental stability was explored.It was found that their weights decreased by13.97%and 8.24%before and after 24 hours.And TG characterization found that the water loss of KOH/PVA is about 45%higher than that of C₈H₂₁NO/PVA,which proves that the environmental stability of C₈H₂₁NO/PVA gel electrolyte is better;the two electrolytes are applied to the elastic capacitor cord and stretched.The test found that the loads used to break the two ropes were 112.3 N and 115.3 N,respectively.It can be seen that the two gel electrolytes basi cally have no effect on the mechanical properties of the capacitor rope.Activated carbon materials of different compositions were selected to conduct assembly and electrical performance tests on the capacitors.The morphology of the activated carbon material was characterized by SEM,and the aramid fiber-based elastic capacitor was assembled together with the gel electrolyte.After testing,it is found that when the ratio of activated carbon:PVDF:acetylene black is 8:1:1,the electrochemical performance of the aramid fiber elastic capacitor is the best,and the specific capacitance can reach 0.924 m F·cm^-1.The electrochemical stability of the aramid fiber-based elastic capacitor was systematically studied,and it was found that the capacitance retention rate of the aramid fiber-based elastic capacitor can reach 92.18%when the CV test cycle is 1000 cycles;when bending at different angles,the capacitance performance is almost no change;after bending 500 times,the capacitance retention rate is 82.19%;when the tensile deformation becomes75%,the capacitance retention rate is 79.45%.In general,aramid fiber-based elastic capacitors exhibit good flexibility and good electrochemical stability.Based on the aramid fiber-based elastic capacitor,a bridge rectifier circuit was designed to rectify and filter the alternating current signal,and the function verification of the elastic capacitor was realized.