Preparation And Properties Of Printable Flexible Supercapacitor

With the increasingly sharp contradiction between the energy demand generated by social development and the actual depletion of traditional energy,which makes people realize that it is imperative to improve energy utilization and develop green energy storage devices.Since entering the 21st century,Various flexible,foldable and wearable emerging smart devices have been widely used in flexible screen,intelligent wound dressing,electronic skin and intelligent robot.It is necessary to develop a flexible energy storage equipment with low price,good security and excellent performance to meet the normal energy supply of these flexible devices under bending or even compression.Flexible supercapacitor is regarded as one of the most promising flexible energy storage devices because of its excellent flexibility,high power density and energy density,long cycle life,high stability and fast charging and discharging.The existing preparation process often has the disadvantages of cumbersome process and high material cost.In this paper,ink is prepared based on the carbon material and conductive polymer,and the flexible supercapacitors are constructed quickly and easily by printing technology without current collector.It has good bending characteristics on the premise of meeting the requirements of electrochemical energy storage,which provides a creative idea for the fabrication of flexible supercapacitor.The main research contents and results in this paper are as follows:（1）Three dimensional framework carbon（3DFC）was prepared by calcining sodium citrate at high temperature,which was used as the framework material and mixed with conductive polymer Poly（3,4-ethylenedioxythiophene）/Poly（styrene sulfonate）solution（PH1000）treated with 5Vol%dimethyl sulfoxide solution,PEODT@3DFC ink was prepared.When the mass ratio of PEDOT and 3DFC is 1:4,the ink has the best electrochemical performance.The PEDOT@3DFC flexible electrode was prepared on cotton,which has a specific capacity of198.13m F cm^-2,wonderful cycling performance and flexibility.（2）Stacked micro supercapacitor and planar flexible micro supercapacitor based on PEDOT@3DFC were fabricated on cotton.The maximum capacity of stack micro supercapacitor is 152.1m F cm^-2,and the capacitance retention rate is 73.3%after 8000 cycles.The maximum capacity of planar flexible micro supercapacitor is 5.45m F cm^-2,and the capacitance retention rate is 72.6%after 3000 cycles.Under the bending conditions of 0°,38°,62°,71°and 92°,there is almost no change in the shape of the Cyclic Voltammetry cycle curve,and the capacitance increases slightly during 1500 times of 92°bending-reset test.（3）Prepared PEDOT@3DFC-CNT Ink and the interdigital supercapacitor prepared with the ink has higher printing accuracy.The device has a specific capacity of 5.53m F cm^-2,and after5000 charge discharge cycles,2.1%capacitance can still be maintained.and it has a maximum energy density of 0.49μWh cm^-2and a maximum power density of 0.8m W cm^-2.Under the bending conditions of 0°,46°,74°,81°and 114°,there is almost no change in the shape of the Cyclic Voltammetry cycle curve.After 6000 times of 114°bending reset,the capacitance increases slightly,and the capacitance change rate is 21.2%.