Banca de DEFESA: LARISSA AGOSTINHO DE SANTA CRUZ OLIVEIRA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : LARISSA AGOSTINHO DE SANTA CRUZ OLIVEIRA
DATE: 29/04/2022
TIME: 14:00
LOCAL: Programa de Pós-Graduação em Ciência de Materiais
TITLE:

SUSTAINABLE ELECTROLYTES BASED ON SEA WATER AND BIOPOLYMERS DOPED WITH IONIC LIQUIDS FOR SUPERCAPACITORS

KEY WORDS:

Gel Polymer Electrolyte. Bio-polymer. Ionic Liquid. Aqueous Supercapacitor.

PAGES: 120
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUMMARY:

This work provides low-cost and sustainable biopolymer gel electrolytes, which are based on seawater (3.5 % NaCl), for application in supercapacitors of active porous carbon. The bio-polymer agar-agar is modified with basic solution NaOH to increase the viscosity performance in 21 folds (82 Pa.s), compared to commercial agar-agar (3.86 Pa.s). This improvement occurs due to an open ring of agar molecule, which favors the formation of cohesive super-fibers in the electrolyte. The electrolytes show improved electrochemical behavior due to the doping of agar-agar with imidazolium ionic liquids. In this regard, ionic conductivity and electrochemical window stability determine the synthesis parameters through the Design of Experiments (DoE).  Despite the highest viscosity, the electrolyte increased the ionic conductivity, when it is compared to the modified agar-agar with the commercial one. It occurs because of the better iteration between agar-agar and the Na+ e Cl-  ions with polymer chain, which favor the conduction by ion jump. The ionic liquids improved the transport properties because of increasing the ion jump and also decreasing the relaxation time of the polymer chain (plasticize effect). Thus, supercapacitors with optimized electrolytes are manufactured with a capacitance, energy, and power density between 2.5-11 F.g-1, 0.4-1.8 Wh.Kg-1, and 117-2565 W.Kg-1, respectively, depending on the applied scan rate (cyclic voltammetry) and density current (galvanostatic charge-discharge). Therefore, the results indicate electrolytes that favor the large-scale production of sustainable supercapacitors. Thus, this work solves the social demand for eco-friendly technologies for energy storage.

BANKING MEMBERS:
Externo à Instituição - Roberto Manuel Torresi - USP
Interno - 1754300 - BRAULIO SILVA BARROS
Interno - 2457389 - EDUARDO PADRON HERNANDEZ
Presidente - 519.487.700-59 - GIOVANNA MACHADO - UFRGS
Externo à Instituição - MARCOS JOSE LEITE SANTOS - UFRGS