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Development of new biodegradable polymer electrolytes for supercapacitor

Sudhakar, Y N (2015) Development of new biodegradable polymer electrolytes for supercapacitor. Phd. Thesis thesis, Manipal Institute of Technology, Manipal.

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Abstract

This thesis involves preparation of blend, gel and solid polymer electrolyte using inorganic salts dopants like lithium perchlorate (LiClO4), lithium tetraborate (Li2B4O7) and acid dopants like H2SO4, H3PO4 and HCl along with plasticizers. The use of these polymer electrolytes are tested in supercapacitor. Electrode materials such as activated carbon and reduced graphene oxide (rGO) are subjected in the fabrication of supercapacitor. In system 1, the miscibility of three blend polymers are determined using Chee, Sun, Huggins theory, heat of mixing, polymer-polymer interaction parameters, blend-polymer interaction parameters. The interaction is further confirmed using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and differential scanning calorimetery (DSC) techniques. Herein, all the preparations showed miscibility only when one of the blend polymer is above 60% in the blend. In system 2, the three blend polymer electrolytes prepared using LiClO4 and Li2B4O7 and electrochemical stability with and without plasticizer and its ionic conductivity are tested at various temperatures (298K to 343K). The Supercapacitor properties like cyclic voltammetry (CV), AC impedance and galvanostatic charge-discharge (GCD) are analyzed. In system 3, three gel polymer electrolyte (GPE) based on biodegradable renewable resources was used in the study. Gelation was brought by adding different plasticizers. Gel polymers were doped with varying amounts of lithium salts and acids. In guar gum based GPE showed unusual tubular array. Highest conductivity of 10-2 S cm-1 is obtained among the gel systems. In system 4, used battery graphite is recycled and converted into reduced graphene oxide using new reducing agent and subjecting it to microwave radiation. Solid polymer electrolyte (SPE) is coated using screen printing technique. The hydroxyethyl cellulose and cellulose acetate propionate SPEs based supercapacitors are also fabricated using activated carbon as electrode material. The stability of SPE is determined in GCD studies. The maximum specific capacitance is 258 F g-1 at 2 mV s-1.

Item Type: Thesis (Phd. Thesis)
Uncontrolled Keywords: Miscibility; Polymer electrolytes; Spectroscopic characterization; Thermal characterization; Electrochemical properties; Supercapacitors
Subjects: Engineering > MIT Manipal > Chemistry
Depositing User: MIT Library
Date Deposited: 30 Apr 2016 15:09
Last Modified: 30 Apr 2016 15:09
URI: http://eprints.manipal.edu/id/eprint/145927

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