Chitosan as biopolymer binder for graphene in supercapacitor electrode

Abstract

This study reports the effect of different weight percentages of chitosan binders in the graphene electrode on the distribution or homogeneity and electrochemical behaviour. The homogeneity of the chitosan binder is characterized by microstructural and structural analysis. Cyclic voltammetry and galvanostatic charge-discharge are employed to investigate the electrochemical performance and life cycle of these electrodes for supercapacitor application. The best weight percentage of chitosan binder is 10 wt%, leading to good homogeneity and bonding. The highest specific capacitance of this electrode is 135.65 F g−1, with retention of 87.2% over the repeated charge-discharge cycle. The fabrication of asymmetric supercapacitor (MnO2–graphene–chitosan//graphene–chitosan) has a decent energy density of 80.40 Wh kg−1 at a power density of 2894.61 Wh kg−1. A cycling test revealed it has 74.18% retention of its original capacitance after 1000 cycles at 1.2 A g−1. The fabrication of 10 wt% chitosan binders in the graphene electrode showed excellent properties.