Sulfated cellulose/polyvinyl alcohol composites as proton conducting electrolyte for capacitors

摘要

Supercapacitors are attractive devices for energy storage because of their high power density. Electrolytes are important components in supercapacitors because their electrochemical properties directly influence the performance and the internal resistance of the capacitor. In this work, cellulose was modified to be used as an electrolyte. Sulfated cellulose (SC) was prepared by esterification of micro-crystalline cellulose and characterized by elemental analysis, gel permeation chromatography and x-ray diffraction. The sulfated cellulose was dispersed in polyvinyl alcohol (PVA) solution to fabricate a proton conducting electrolyte. The SC/PVA (85:15 % w/w) film activated with 0.25M H2SO4 show high ionic conductivity of 2.5 × 10~(-1) S/cm and specific capacitance of 96 F/g at 25°C. In the charge-discharge curves, a low internal resistance was observed for SC/PVA electrolyte as compared to the acidic solution electrolyte.