Synthesis And Characterization Of Tailorable Or Electrochromic Flexible Electrodes And Supercapacitors

Supercapacitors,as a new kind of efficient energy storage devices between traditional electrochemical batteries and conventional capacitors,have attracted increasing attention because of their high power density,fast charging and discharging rates,long cycle life and safety.With the further development of science and technology,convenient,intelligent wearable electronic products began to spread,and the traditional supercapacitors are unable to meet the application requirements of these electronic products due to the lack of flexibility and their large volume.Flexible solid state supercapacitors have become the current research hot spots because of their good flexibility,portability and own the potential to achieve diverse integrated functions.However,the key technical problem of flexible solid supercapacitors is the poor energy storage and mechanical properties of electrode materials.In this paper,based on the capacitive materials such as carbon nanotubes(CNT),polypyrrole(PPy),MnO2 and WO3,flexible electrodes and supercapacitor with tailorable and electrochromic characteristics have been designed and constructed.The main contents and conclusions are summarized as follows:1.The PPy nanoparticles were synthesized by a facile chemical polymerization reaction,and the freestanding CNT-PPy flexible hybrid electrode was obtained by vacuum filtration method.Finally,tailorable flexible supercapacitors were assembled.The as-synthesized CNT-PPy electrode displays an excellent electrochemical performance(596.9 mF·cm-2 at 4.0 mA·cm-2).Flexible symmetric supercapacitor based on the CNT-PPy hybrid electrode showed remarkable flexibility and tailorability,with no significant decay under bending state.In addition,when these supercapacitors are cut down by half of their size,the capacitance retention was ~50%,suggesting that the tailoring process can hardly affect their performance.2.The MnO2 nanowires(NWs)were synthesized by hydrothermal method and the flexible tailorable supercapacitor based on CNT-MnO2 NWs was prepared.The CNT-MnO2 hybrid electrode has a specific capacitance of 135.1 mF·cm-2 when the current density is 2.0 mA·cm-2.In addition,the flexible tailorable supercapacitor based on CNT-MnO2 NWs also has excellent electrochemical performance,cycling stability,flexibility and tailorability.3.The WO3 based flexible electrochromic supercapacitor electrodes were designed and prepared by physical vapor deposition process and employing novel silver nanowire based flexible transparent conducting substrates.The as-prepared electrode exhibits great electrochemical performances(138.2 F·g-1 at 10.0 mV·s-1).Furthermore,this electrode shows high coloration efficiency(80.2 cm2·C-1)and fast response speed(coloring in 1.7 s and bleaching in 1.0 s).