Solution Jet Spinning Of Nanofiber Yarns And Their Application In Supercapacitors

With the appearance of smart wearable devices,yarn-shaped supercapacitors has attracted more and more attention because of its good flexibility,light quality,simple process and easy integration with garment.In recent years,the development of oriented nanofiber yarns and its application in yarn-shaped supercapacitors has achieved results.But it is still difficult to realize industrial production.Solution blown is a method to realize the industrialization of nanofiber yarns.Based on the typical solution blown device,the preparation system of nanofiber yarn was obtained by adding collection and twisting device.The PAN nanofiber（PAN NFs）yarn was prepared by self-made spinning device,and the feasibility of solution blown device was explored.In order to improve the mechanical and electrical properties of the yarn,carbon fiber bundle（CFs）was used as the core yarn to prepare the PAN NFs/CFs core-spun yarn.PPy/PAN NFs/CFs yarn electrode was obtained by in-situ polymerization.The yarn forming process and the synthesis process of polypyrrole were explored.The basic properties and electrochemical properties of the electrode material were tested and analyzed.The main research contents and conclusions are as follows:（1）Preparation of PAN NFs yarns with different mass fractions（6%,8%,10%,12%and 15%）PAN solution by a self-made solution blown device.The morphology and structure of nanofiber yarn were characterized by scanning electron microscope.The orientation of the 10%-PAN NFs was the best and its fineness was uniform,the spinning effect was the best,.（2）The electrochemical performance of the PPy/PAN NFs yarn electrode were studied by grafting PPy on the PAN NFs yarn by in-situ polymerization.The areal capacitance of PPy/PAN NFs yarn electrode was 571.8 m F cm^-2,and the yarn-shaped supercapacitor was 208.8 m F cm^-2,the cycle retention rate was 63%after 2000 cycles.（3）In order to improve the mechanical and electrical properties of the yarn electrode,using CFs as core yarn to prepare PAN NFs/CFs.The effect of yarn structure and polymerization time on the electrochemical properties of yarn electrode were studied.The results showed that 1 h-PPy/10%-PAN NFs/CFs performance best and the areal specific capacitance was 649 m F cm^-2.（4）1h-PPy/10%-PAN NFs/CFs was used as electrode to assemble yarn-shaped supercapacitors.When the gel electrolyte was PVA/Li Cl/H₃PO₄（6:3:3）,the areal specific capacitance of was 353 m F cm^-2,and the cycle stability was improved(10000^th,77%).And the energy density and power density were 24.74μWh cm^-2and127.23μW cm^-2,respectively.The specific capacitance had little change under different bending angles.