Preparation,Properties And Applications Of Gel Polymer Electrolytes

Gel polymer electrolyte has the advantages of wide operating voltage range and relatively stable system.It can solve the disadvantages of liquid electrolytes that are volatile and leak,and also has high ionic conductivity compared with the solid electrolyte.The gel polymer electrolyte is considered to be one of the most promising electrolytes for supercapacitors.In this dissertation,gel polymer electrolytes were prepared from cellulose pulp and polyvinyl alcohol?PVA?as the matrix.And they were modified with redox substances.The physical structures and electrochemical properties of them were analyzed and characterized.The details were as follows:Using cellulose pulp as raw material,XWD-NaOH electrolyte was prepared by chemical crosslinking.The ionic conductivity of this gel electrolyte was 6.12 mS·cm^-1.The specific capacitance?Cs?of the supercapacitor with XWD-NaOH electrolyte was 56.3F·g^-1.The power density and energy density of the supercapacitor were 99.2 W·kg^-1 and0.7 Wh·kg^-1,respectively.Physical structure characterization results showed that it had a porous structure.The XWD-NaOH-K₄[Fe?CN?₆]electrolyte was prepared by doping the potassium hexacyanoferrate?K₄[Fe?CN?₆]?into the XWD-NaOH electrolyte.The ionic conductivity of this gel electrolyte increased to 15.24 mS·cm^-1.The Cs of the supercapacitor increased to 88.4 F·g^-1.The power density and energy density of the supercapacitor increased to209.7 W·kg^-1 and 0.7 Wh·kg^-1,respectively.The presence of K₄[Fe?CN?₆]improved the electrochemical performance of the supercapacitor.Using the impregnation method,XWD-NaOH-KI/I₂ electrolyte could be prepared and applied to dye-sensitized solar cells,showing good performance.The photoelectric conversion efficiency test results showed that the photoelectric conversion efficiency could reach up to 60%at 600 nm.Using PVA as raw material,PVA-H₂SO₄ gel polymer electrolyte was prepared by physical cross-linking method.The ionic conductivity of this gel electrolyte was 10.12mS·cm^-1.The Cs of the supercapacitor with XWD-NaOH electrolyte was 88.1 F·g^-1.The power density and energy density of the supercapacitor were 238.5 W·kg^-1 and 2.8Wh·kg^-1,respectively.The PVA-H₂SO₄-ARS electrolyte was prepared by doping the dye alizarin red?ARS?into the PVA-H₂SO₄ electrolyte.The ionic conductivity of the gel electrolyte reached to20.31 mS·cm^-1.The Cs of the supercapacitor increased to 113.6 F·g^-1.The power density and energy density of the supercapacitor increased to 242.0 W·kg^-1 and 3.7 Wh·kg^-1,respectively.The PVA-H₂SO₄-ARS-MB electrolyte was prepared by doping the dye methylene blue?MB?into the PVA-H₂SO₄-ARS electrolyte,which further improved the Cs of the supercapacitor and improved the cycle performance of the system.The gel polymer electrolytes synthesized above were expected to be used in supercapacitors and solar cells.