Application Of Redox Gel-electrolyte In Supercapacitor Based On PEDOT/CP

As fossil resources are becoming increasingly scarce and the amount of solid particles in the air is increasing by their emissions,causing haze more serious,the safety of human life is directly threatened.So more and more people are starting to research and develop new energy installations.Among them,supercapacitor has been widely used in standby power system,portable electronic equipment and electric vehicle et.,because of its large capacity,high power density,maintenance-free,no pollution to the environment and long cycle life.In order to increase the stability of supercapacitor,improve the electrochemical performance and reduce the cost,the supercapacitors based on PEDOT/CP were systematically studied.The study,on one hand,aims to use the ability of gel polymer electrolyte to penetrate inherently into the electrode pores and convenience in terms of handling and packaging to reduce costs and increase capacitance.On the other hand,it based on the redox active material in the electrolyte,which introduces an additional pseudo-capacitance effect for the system to improve the capacitance of the supercapacitor.Moreover,the performance of super capacitors is improved due to the introduction of two kinds of redox additives in the electrolyte.Therefore,the present study mainly focuses on the performance of PEDOT/CP based supercapacitors under different gel electrolytes.It includes PVA/H₂SO₄,PVA/H₂SO₄/PB,PVA/H₂SO₄/KI,and PVA/H₂SO₄/PB/KI.And the four systems of study is not the isolated and parallel experiment,rather than having close relationship.The study is carried outstep by step in a gradually deeply manner.It could be said that the later stage study is on the basis of the assumption that arised from the experiment results of the last stage study.Taking into account the large-scale application of supercapacitors,the cost of supercapacitor production need to be reduced.So the development of cheap,easy and excellent performance of the base material will become a research trends in supercapacitor.In this paper,the three-dimensional PEDOT/substrate composite electrodes ware prepared on carbon substrate（CP）,stainless steel mesh（SSM）,stainless steel（SS）and indium tin oxide（ITO）,respectively.The relationship between the morphology and the electrochemical properties of these electrodes was systematically studied by combining scanning electron microscope（SEM）and FourierTransform Infrared spectroscopy（FT-IR）with electrochemical tests（Cyclic voltammetry,Galvanostatic Charge-Diacharge,electrochemical impedance spectroscopy and stability）.It was found that the PEDOT/CP electrodes have excellent capacitance properties due to its porous porous three-dimensional nanofiber structure.The high performance electrode materials provided for the following studies.The PVA/H₂SO₄ gel electrolyte,structurally speaking,has inherent ability to penetrate into the electrode pores and the same diffusivity as the liquid electrolyte,resulting in increasing in supercapacitor performance.Simultaneously,it avoids leakage of liquid capacitors.It was found that although its energy density was increased（but only 3.3784 Wh/kg）,it is still at a low level in the supercapacitor.On the basis of the above research results,it is considered whether or not the energy density can be improved by introducing the redox additive into the electrolyte by using the pseudo-capacitance effect caused the redox reaction at the electrode surface.In this paper,PVA/H₂SO₄/PB gel-polymer electrolyte was prepared by directly impregnating PVA/H₂SO₄ gel-electrolyte with p-Benzenediol（PB）as redox activity,and it was applied to PEDOT/CP supercapacitor.The electrochemical performance of PEDOT/CP supercapacitor based on this novel gel polymer was studied by electrochemical technique.It is found that although the capacitance（76.2624 F/g）,the energy density（6.7789 Wh/kg）and the stability are significantly improved in the PVA/H₂SO₄/PB supercapacitor,the energy density still needs to be further improved.The PVA/H₂SO₄/KI gel polymer used in PEDOT/CP supercapacitors was prepared by directly impregnating the PVA/H₂SO₄ gel electrolyte with KI as a inorganic redox additive with lower cost and stronger ion diffusion performance（relative to PB redox additive electrolytes）.The electrochemical performance of PEDOT/CP based supercapacitors based on this novel gel polymer was studied by electrochemical technique.It is found that due to the oxidation-reduction reaction of I-/I2,an additional pseudo-capacitance effect is introduced for the system and make the specific capacitance（683.8284 F/g）and the energy density（243.1390 Wh/kg）of the PVA/H₂SO₄/KI gel electrolyte supercapacitor significantly improve.But its magnification performance and stability is extremely poor.Study on PVA/H₂SO₄/PB/KI gel electrolyte Supercapacitor.The study of this stage is summarized from PVA/H₂SO₄/PB and PVA/H₂SO₄/KI part experience results.The original start point is whether the magnification performance,stability of organic additives（PB）and rapid diffusion of ions of inorganic additives（KI）could be use to drive the PVA/H₂SO₄ at the same time.It play a key role in promoting the performance of supercapacitors.The present part study is the extention of the prvious two study.The experimental results was showed that the PEDOT/CP supercapacitor based on the new PVA/H₂SO₄/PB/KI gel electrolyte reveals excellent specific capacitance（147.8796 F/g）,energy density（82.1553 Wh/kg）and cycle durability.A new thinking was provided for the new green energy storage.