The Application Of Flexible Conductive Polymers/Nanofibrous Textile Electrodes In Supercapacitor

Supercapacitors?SC?are able to store more energy and possesses higher energy density when compared with traditional capacitors,and besides,the rapid charge-discharge ability as well as long cycling life are also the superiorities of SC in comparison with secondary batteries.Furthermore,SC is an environmentally friendly energy storage device.All advantages mentioned above make SC a new research hotspots.However,with the upgrade of technology and products,the previous rigid electrodes could not meet the requirements of modern new products gradually.Flexible electrodes can be widely applied in wearable devices or some special conditions due to their foldable and bendable properties.As a result,flexible electrodes have much more applied potential and market values.This study is mainly in-situ polymerizing conductive polymers��polyaniline?PANI?and polypyrrole?PPy?on the three-dimensional flexible substrates PVA-co-PE nanofibers/PET non-woven?NFs/PET?through chemical oxidation,which produces conductive composites used as flexible electrodes of SC.These electrodes are characterized for their morphologies,chemical structures and conductivities.Also,the electrochemical properties of these electrodes and the symmetrical SC devices composed of them have been tested.Besides,the influences of amounts of NFs and morphologies of PPy on electrochemical performances for electrodes have been investigated.The amounts of NFs on substrates of PANI electrodes are 0,4.0,5.4 and 7.1 g m^-2,in which the electrode containing 5.4 g m^-2 NFs?designated as PANI/NFs/PET-5.4?has superior conductivity and electrochemical performances whose Csc reaches a value of 1.47 F cm^-2(503F g^-1)when Sv is 1 mV s^-1 and Csd is 1.58 F cm^-2(543 F g^-1)when Id is 1.0 mA cm^-2.The symmetrical SC device composed of PANI/NFs/PET-5.4 has a Rc of 76% after 2500 cycles at5 mA cm^-2.The all-solid symmetric device assembled by PANI/NFs/PET-5.4 obtains a maximum Csd of 0.146 F cm^-2 during the 6000 cycles at Id of 6 mA cm^-2,and still maintains0.131 F cm^-2 at last.As for PPy electrodes,the differences of them are PPy structures with nanowires orirregular agglomerate shapes and if there are NFs on the substrates.Above them,the electrode with PPy nanowires and NFs?designated as NW-PPy/NFs/PET?obtains the best performances.For this electrode,the Csc reaches a value of 323 F g^-1 when Sv is 5 m V s^-1 and Csd is 420 F g^-1 when Id is 2 A g^-1.And the Rc of symmetrical SC devices composed of four electrodes respectively are all higher than 61% after 500 cycles at 0.25 A g^-1.For the all-solid NW-PPy/NFs/PET symmetric device,the highest Csd during the 6000 cycles is 82 F g^-1 at Id of1 A g^-1,and ultimately,Rc still maintains 65.8%.