The Preparation Of Cotton-based Carbon Nanotubes/Polypyrrole Electrode And Its Electrochemical Properties

Electrochemical capacitor is a novel storage between conventional capacitors and batteriesdevice, electrode material is a key factor influencing the performance of supercapacitor. The fiberhas the incomparable characteristics of large specific surface with other sheet materials, the fabricis used as a carrier of the energy storage unit, forming a light battery electrodes andelectrochemical capacitor, through assembling the conductive nano-structure material on thesurface.Most research focus on the fabric-based functional materials because of its flexible andcollapsible.The present study about electrochemical capacitors mainly focus on the preparation andmodulation of structure and properties for high performance porous electrode materials,one of themost important way to improve the capacity of electrode is to find porous materials as compositeelectrode carrier of active materials, including high surface area carbon materials (such asactivated carbon, carbon nanotubes and graphene) and conductive polymers (such as polyaniline,polypyrrole, polythiophene and its derivatives, etc.).The main technical difficulties including thecombination between two kinds of electrode active materials with different properties and itsadhesion on a flexible substrate.At present, the solution impregnation with several times isapplied. This method is easy to cause the surface functional layer off because of its inter-facialadhesion is weak;Another common method is adding the electrode active material to adhesive,then coated on the surface of fabric, which may increase the overall electrode material resistance,and is not conducive to the formation of porous structure at the same time.This thesis prepared different structures of CNT/PPY nano structure of sedimentary layer in alarge area of cotton fabric (Ctn) substrate by template polymerization, interfacial polymerizationand pulse electrodeposition in-situ technique respectively,formed with a variety of flexibleelectrode material of energy storage performance.Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), X ray diffraction (XRD) wasused to characterize the structure and morphology,studying volt ampere characteristic curve,constant current charge discharge curves, electrochemical impedance spectra about itselectrochemical performance.The results showed that:With twelve sodium dodecyl benzene sulfonate (SDBS) and sixteen alkyl three methylammonium bromide (CTAB) as a soft template to prepare m-Ctn/PPY,and then use two stepand one step template polymerization to prepare m-Ctn/CNT/PPY, sheet resistance were59.8±12.9Ω/sq and144.6±21.7Ω/sq,and the specific capacitance were377±34.3F/g and238.7±31.0F/g, respectively. The two step polymerization formed folds like PPY covering on the surfaceof the fabric; In one step polymerization, PPY grow along the nanotube to form PPY nanowires.Afull charge and discharge time of m-Ctn/PPY is less than300s, while j-Ctn/CNT/PPY is up to500s,After1000cycles of charge and discharge, the capacitance of m-Ctn/PPY decreased by33%, while the j-Ctn/CNT/PPY decreased by8.1%.The j-Ctn/PPY j-Ctn/CNT/PPY made by self-designed interface polymerization have, theresistance of198.2±35.6Ω/sq and107.4±18.3Ω/sq, the specific capacitance were180.9±70.4F/g and285.45±51.4F/g,respectively.Besides, j-Ctn/PPY have the "Coral" structure,j-Ctn/CNT/PPY obtained coral and flower PPY nanowires according to CNT add into the oil orwater phase,respectively.This three-dimensional structure has good reversibility in the chargedischarge cycle.A full charge and discharge time of j-Ctn/PPY is less than200s, whilej-Ctn/CNT/PPY can reach more than800s.After200cycles of charge and discharge, thecapacitance of j-Ctn/PPY decreased by36.8%, while the j-Ctn/CNT/PPY edecreased by6.9%.Pulse electrodeposition prepared d-Ctn/CNT/PPY have the sheet resistance and specificcapacitance of1241.5±186.2Ω/sq and170.0±16.2F/g, with cauliflower like struture.a fullcharge and discharge time of d-Ctn/CNT/PPY is about200s, after1000cycles of charge anddischarge, the capacitance decreased by8.5%.