Banca de DEFESA: AMANDA BARRETO SOARES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : AMANDA BARRETO SOARES
DATA : 12/03/2021
HORA: 14:00
LOCAL: videoconferência na plataforma RNP (sala PEI-UFBA)
TÍTULO:

Evaluation of the use of V2O5 produced by Vanádio de Maracás (Bahia) for the production of electrolytes used in vanadium redox battery.

PALAVRAS-CHAVES:

Vanadium pentoxide; vanadium redox battery; electrochemical performance.

PÁGINAS: 116
GRANDE ÁREA: Engenharias
ÁREA: Engenharia de Produção
RESUMO:

Vanadium is a chemical element and in vanadium compounds occur naturally in about 65 minerals and in fossil fuel deposits. It is mainly used to produce steel alloys in the metallurgical industry and as catalysts in chemical reactions. It is usually marketed as vanadium pentoxide, which in turn is one of the main raw materials in the production of vanadium electrolytes used in vanadium redox battery systems for energy storage. Among the chemical compounds of vanadium sold, vanadium pentoxide has the lowest cost price, thus becoming the favourite in the manufacturing of vanadium electrolytes. The purpose of this paper is to assess the use of vanadium pentoxide produced at the Vanádio de Maracás S/A (VMSA) plant as a raw material in the manufacture of vanadium electrolytes. Atomic absorption spectroscopy and electrochemical performance tests were carried out in the laboratory, along with analysis of electrolytes by cycle voltammetry and loading-discharge tests. Electrolytes containing 0.114 mol.L-1 vanadium and 3 M H2SO4, and cell potential of 1.14 V, were produced from VMSA vanadium pentoxide. The results of cyclic voltammetry showed that in the V(II)/V(III) electrolyte the oxy-reduction reactions between the pair V2+ and V3+ have characteristics of a quasi-reversible system, and in the V(IV)/V(V) electrolyte the reactions between the pair V4+ an d V5+ have characteristics of a reversible system. It was also observed that when adding sodium and magnesium sulphate in 5 M H2SO4 solutions, there is the precipitation of vanadium pentoxide. In charge-discharge tests with the electrolyte containing 0.114 mol.L-1 vanadium and 3 M H2SO4 in solution, the battery showed 90.1% coulombic efficiency, 98.3% voltage efficiency and 88.5% energy efficiency, compared to other developed energy storage systems. After some charge-discharge tests, strong wear was observed on graphite electrodes, severely compromising the energy efficiency of the cell.

MEMBROS DA BANCA:
Externo(a) à Instituição - LUIS ALBERTO DANTAS BARBOSA
Externo(a) à Instituição - LUIZ GONZAGA SANTOS SOBRAL
Presidente - 287167 - LUIZ ROGERIO PINHO DE ANDRADE LIMA