Electrical characterization of corn starch-LiOAc electrolytes and application in electrochemical double layer capacitor

•Addition of glycerol enhances the conductivity up to (1.04 ± 0.10) × 10−3 S cm−1.•LSV has shown that the polymer electrolyte is suitable for fabrication of electrochemical device.•The fabricated EDLC has been charged and discharged for 1000 cycles.•The specific capacitance calculated from CV is comparable with the specific capacitance calculated from galvanostatic charge-discharge cycling.

Corn starch based solid biopolymer electrolytes doped with lithium acetate (LiOAc) and plasticized with glycerol are prepared by solution cast technique. In unplasticized system, the maximum room temperature conductivity of (2.07 ± 0.53) × 10−5 S cm−1 is obtained by the electrolyte consists of 75 wt.% starch and 25 wt.% LiOAc. In plasticized system, addition of 30 wt.% glycerol to the highest conducting unplasticized electrolyte has further increase the conductivity up to (1.04 ± 0.10) × 10−3 S cm−1. Results from X-ray diffraction (XRD) explain that the enhancement of conductivity is contributed by the degree of crystallinity of electrolytes. Linear sweep voltammetry (LSV) shows that the highest conducting plasticized electrolyte is stable up to 2.1 V. The highest conducting plasticized electrolyte is used in the fabrication of an electrochemical double layer capacitor (EDLC). The EDLC is characterized using cyclic voltammetry (CV) and galvanostatic charge-discharge measurements. From CV, the specific capacitance (Cs) of fresh EDLC is calculated to be 33.00 F g−1 at scan rate of 0.5 mV s−1. The value of Cs increases as the scan rate decreases. From the charge-discharge measurement, the value of Cs is almost constant at ∼ 33.31 F g−1 for 1000 cycles.

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