Fabrication And Properties Of Flexible Electrodes And Their Energy Storage Devices

Recently,flexible/wearable consumer electronics has aroused extensive attention because of its fascinating properties,such as light weight,portability,durability,bendability and wearability.As the fundamental building blocks to power electronics,energy-storage devices are essential for the startup and operation of electronic devices.The portable flexible supercapacitor has become an energy storage device with great development potential and good application prospects.However,the bottleneck of the application of flexible supercapacitors?FSCs?is concentrated in two aspects.On the other hand,the current manufacturing processes of FSCs involve high-difficult,high-loss processes such as laser etching,high-pressure pressing and masking.There is a lack of technically simple and cost-effective manufacturing processes to easily achieve low cost and expand production.In view of the above bottlenecks,this thesis is devoted to the development of new electrode materials and the exploration of new preparation processes making sure that high-performance Supercapacitors can be produced with low cost and large area.The research content mainly includes electrode material synthesis,active material ratio,supercapacitor preparation,experimental process optimization,photoelectric performance characterization and device application.?1?A new type of Ag/MnO₂ composite based electrode was fabricated by combining the manufacturing process of inkjet printing with the additive reduction and the simple electrochemical deposition method and the rinsing auxiliary method,and further assembled into a planar flexible supercapacitor with great comprehensive performance.A technical scheme for preparing flexible supercapacitors by inkjet printing was established.A flexible substrate:polyethylene terephthalate?PET?was selected,and nano silver particles were uniformly printed on the flexible substrate,and the wettability and film formation of the substrate are improved by adjusting the printing parameters.The idea of composite electrode fabrication was proposed.The high specific capacitance material MnO₂ was obtained on the silver electrode by electrochemical deposition,and the formation of MnO₂ with unique nano-fibrous network structure was completed by controlling the electrochemical deposition time and the scouring aid.These methods promote the transport of electrolyte ions,thereby optimizing the electrochemical performance of FSCs based on Ag/MnO₂(46.6 mF·cm^-2).The FSCs also exhibited a high energy density of 17.5 Wh·kg^-1(23.37 mJ·cm^-2)at a power density of 500.95 W·kg^-1,and the specific capacitance was only slightly lowing after the FSCs was bent 1000 times at a height of 180°.The specific capacitance retention rate is 86.8% of the original value,showing excellent flexibility.By means of the excellent patterning ability of inkjet printing,various series and parallel FSCs can be directly and simply produced by inkjet printing without the use of external metal interconnection and cumbersome procedures.?2?Organic gel electrode made of PEDOT:PSS with three-dimensional nanostructures was compounded by means of injection molding design fold structure of conductive organic gel network,weakening the negative impact of the incompatibility of organic solvent for organic gel,resulting in good comprehensive properties of elastic gel super capacitor.Combining the pseudocapacitance and the double layer theory,the charge storage performance of FSCs is improved greatly and the advantages of mesoporous structure in charge transfer and ion exchange are proved.FSCs that based on PEDOT:PSS organic gel electrode has a high area-specific capacitance of 227 mF·cm^-2,and the capacitance retention rate of gel FSCs is 77.19%after 3000 cycles of charging and discharging,showing that FSCs has good cycling stability,which provides a new way to improve the electrochemical properties of conductive polymer and a beneficial enlightenment to develop high-performance polymer electrode materials for electrochemical energy storage.?3?A simple,low-cost,environmentally friendly copolymerization process have been developed by combining the conductivity of PEDOT:PSS with the mechanical flexibility of polyacrylamide?PAAm?,and then a high performance stretchable composite based on PEDOT:PSS/PAA gel was synthesized,and a good balance of light transmission,mechanical flexibility and electrochemical performance of high performance devices was achieved.High-performance devices made of composite materials achieve a good balance of light transmission,mechanical flexibility and electrochemical performance.A mold-forming electrode technology was established.The copolymerization pre-reaction solution was injected into a special-sized glass mold.A new stretchable electrode based on PEDOT:PSS/PAAm gel with controlled size and good comprehensive properties was prepared by one-step copolymerization.By adjusting the monomer concentration of acrylamide?AAm?and the post-acidification treatment conditions,the conductivity of the gel electrode was improved,and the electrochemical performance of FSCs based on PEDOT:PSS/PAAm(206.8 mF·cm^-2)was optimized.When the FSCs was stretched to 3/2 of the original length,the specific capacitance retention rate was 74.9% of the original value,showing excellent stretchability.The synthetic PEDOT:PSS/PAAm gel also has excellent light transmission properties?T:64%?by using a special mold to effectively control the area and thickness of the gel.The PEDOT:PSS/PAAm gel-based FSCs is guaranteed to have excellent light transmission,good mechanical flexibility and high electrochemical performance.