Research On Construction And Performance Of Flexible Supercapacitor Based On Helical Carbon Nanotube

With the emergence of flexible intelligent wearable electronic products,it is urgent to develop the corresponding flexible energy storage devices.Traditional energy storage devices are difficult to meet the needs of flexible electronic devices.As a novel energy storage device,flexible supercapacitor（FSC）has attracted wide attention from researchers for its characteristics of high power density,high flexibility and high safety.Carbon nanomaterials,especially helical carbon nanotubes（HCNT）,have remarkable advantages in flexible device applications due to their high flexibility,special coiled structure and excellent photoelectric performance..Therefore,in order to prepare more flexible supercapacitor with higher capacity,this article uses HCNT as precursor,carbon composite material are designed through the nitrogen（N）doping,recombining reduced graphene oxide（RGO）and in-situ polymerize polyaniline（PANI）,the specific contents are as follows:（1）A flexible self-supporting carbon-based film with efficient electronic transmission network and good structural stability was constructed by solution self-assembly method,,which was directly used as the FSC electrode.The contact resistance of the composite material is reduced by using the special spring-like structure and mechanical interlock effect of HCNT.By taking advantage of good dispersion properties of GO,it acts as a unique two-dimensional carbon nanostructure template to facilitate the formation of microporous and mesoporous structures and further improve the mechanical and conductance characteristics of the electrode.The results showed that the GC2（RGO/HCNT=10:2）electrode showed good electrochemical characteristics,the specific capacitance generated 336 Fg^-1at the current density of 0.25Ag^-1,and the capacitance retention rate of 89.5%was shown for 3000 cycles of charging and discharging.Most importantly,flexible devices work at different bending angles,and their capacitance is almost unaffected.HCNT can be used as an ideal material for building flexible devices（2）N-doped RGO/HCNT composite electrode material（NGC）was synthesized by hydrothermal method.Urea was used as the dopant to improve the wetness and conductivity of the composite electrode and electrolyte.Combining the advantages of rich N active sites and high conductivity effectively improve the charge storage capacity of the electrode.The maximum specific capacitance of NGC after nitrogen doping is349 Fg^-1,with good cyclic stability(only 9.8%capacitance is lost after 3000charge/discharge cycles under 0.5Ag^-1).（3）PANI/RGO/HCNT carbon cloth composite electrode materials（PANI-GC2）was designed by in situ polymerization.the electrostatic interaction between-COO-group of RGO/HCNT with-NH-of PANI chain andπ-πinteraction of with carbon cloth as the driving force,the uniform stability of RGO/HCNT composites combining PANI form cellular structure,resulting in strengthening the compactness of PANI and GC2composites,the maximum capacity can reach 557.5 Fg^-1.The pseudocapacitance of PANI makes PANI-GC2 cycle stability excellent,After 3000 cyclic charge and discharge tests,it accounts for about 90.3%of the initial capacity.