Design And Flexible Construction Of High Performance Supercapacitors Electrode Materials

With the rapid development of light,flexible and wearable electronic devices,supercapacitors have become a new type of energy storage device.Supercapacitors have the incomparable superiority compared with other power storage device,mainly due to high power density,fast charge and discharge rate,flexibility,light weight,low cost and environmental friendliness.The composition and structure of electrode material directly determine the energy storage performance of supercapacitor.Traditional flexible supercapacitors are made by mixing active materials,conductive agents and adhesives,and then coating them on foam nickel.The disordered dispersion of the conductive agents and adhesives in the active materials will reduce the effective specific surface area,ion transport capacity,material lifetime,capacitance,and energy density ration.In order to solve the problem mentioned above,this article investigated the modification and complex method of the carbon electrode materials and metal oxide electrode materials of the supercapacitor.The research mainly focuses on three aspects:?1?The micro nano structure design of the electrode material can increase the effective specific surface area and specific capacitance;?2?Adding the conductive phase to enhance the ion transmission capacity;?3?Choosing the appropriate combination method to increase the binding force between the active material and the collector.The content of this research is as follows:Self-made nano-Ag was used as a conductive material,SDS was used as a dispersant,and ethanol and deionized water were used as a solvent to prepared a nano-Ag paste that can be used for direct writing.When the heat treatment temperature was 90°C and the heat treatment time was 2 hours,its resistivity can reach 6.8×10^-4?·cm,so it can be used as the conductive film layer of carbon material flexible electrodes.The Ag and CNTs were coated on the paper-based fiber network by direct writing to improve the specific surface area of the electrode material,and this fiber network can be used to prepare a flexible Ag/CNT composite electrode.The electrochemical performance of Ag/CNT flexible electrode and its possibility to be used as flexible supercapacitor electrode were analyzed and studied.The experimental results show that the by doping of Ag conductive phase the resistivity of electrode can be 5.1×10^-4?·cm,which was 25.1%less than the Ag electrode,and 98.2%less than the CNT electrode.TiO₂ nanotubes with large surface area were prepared on flexible titanium foil by anodic oxidation.Since anodization was an in-situ synthesis,the TiO₂ nanotubes have good bonding properties with titanium foils.After N-ion Implantation,the surface morphology of TiO₂nanotubes obviously changed.When the implantation dose of N-ion was 10.0×10¹77 ions·cm^-2,needle structure appeared at the top of the nanotubes.TiN-based compounds produced by N-ion doping can greatly improve the conductivity of TiO₂ and its resistivity was 0.00246?·cm..Compared to unmodified samples,the resistivity was reduced by 5 orders of magnitude.The modified electrode showing high capacitance of 24822.7 m F·cm^-33 at the current density of 0.05m A.When the current density increases from 0.05 to 0.5 mA·cm^-2,the specific capacitance retention rate was 70.0%.After the scanning rate of cyclic voltammetry test was increased from10 to 100 mV/s,the specific capacitance retention rate was 71.7%,which means that our TiO₂/TiN electrode hasgreat rate performance.The TiO₂/TiN electrode has a high charge transfer ability,and its Rct value was 7.731?·cm².To further verify the addition of the conductive phase can improve the electrode activity of the supercapacitor,we injected Ag ions into TiO₂ nanotube arrays by metal vapor vacuum arc implantation to prepare the flexible The Ag amount were facilely controlled via adjusting ion implantation parameters.When Ag ion implantation dose was 5.0×10¹77 ions·cm^-2,the top of TiO₂ nanotubes showed an island-like continuous network structure.Compared with different doses of Ti O₂/Ag,the dose of 5.0×10¹77 ions·cm^-22 electrodes exhibited much higher electrode capacity and greatly enhanced activity towards the pure TiO₂ nanotubes.Compared with unmodified samples,its resistivity after Ag-ion implantation was 21.6?·cm which was 95.8%reduced.The modified electrode showing high capacitance of 9324.6 mF·cm^-33 at the current density of 0.05 m A.When the current density increases from 0.05 to 0.5 mA·cm^-2,the specific capacitance retention rate was 54.0%.After the scanning rate of cyclic voltammetry test was increased from 10 to 100 mV/s,the specific capacitance retention rate was 69.5%,which means that our TiO₂/Ag electrode has great rate performance.The TiO₂/Ag electrode has a high charge transfer ability,and its Rct value was 74.79?·cm².