Banca de DEFESA: EWELLYN SILVA SOUZA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : EWELLYN SILVA SOUZA
DATE: 30/11/2023
TIME: 09:00
LOCAL: Programa de Pós-Graduação em Ciência de Materiais
TITLE:

Carbon material modified with transition metal oxides applied to energy storage systems.

KEY WORDS:

Lead-Acid Batteries. Carbon-Black. Dynamic Charge Acceptance. H2 Evolution Reaction.

PAGES: 78
BIG AREA: Outra
AREA: Multidisciplinar
SUMMARY:

In recent years, the automotive industry has required more efficient and reliable leadacid batteries. This demand arises from the use of electrical systems providing various functions to the vehicles, aiming to enhance the driver convenience and some systems to reduce fuel consumption. An example is the start-stop technology that shuts off the combustion engine when the vehicle stops. The batteries used in these vehicles must be robust and efficient enough to withstand numerous engine ignition and keep the electrical systems operational during stops. To meet these demands, the battery industry has been constantly introducing developments to the lead-acid accumulators. For instance, some of the new additives applied to the negative electrodes, such as high specific surface area carbons. Generally, these carbons facilitate the battery's charging and discharging processes due to various modifications in the negative electrode characteristics, which improves the battery charge acceptance. However, many of these carbons increases the evolution of H2 on the negative electrode, increasing water consumption and reducing the device's lifespan. As a strategy to improve charge acceptance performance and reduce the water consumption, it is proposed here the carbon modification with low exchange current for the H2 evolution reaction metal oxides such as Nb and Zn. The oxide was incorporated into the carbon through a hydrothermal treatment using an aqueous solution of soluble metal precursors, followed by drying and thermal treatment in N2 atmosphere. The results obtained in 5 Ah lead-acid cells showed that the carbon modification led to a considerable reduction, approximately 66%, in water loss and a significant increase in charge acceptance efficiency, approximately 89%, compared to the respective pristine carbon. The modified carbon exhibited highly desirable characteristics for application as an additive to the negative electrode of lead-acid batteries and is a strategy to be considered for improving the performance and efficiency of this type of accumulator.

COMMITTEE MEMBERS:
Presidente - 1301657 - ANDRE GALEMBECK
Externo à Instituição - GILBERTO AUGUSTO DE OLIVEIRA BRITO - UFU
Interna - 2163324 - JOANNA ELZBIETA KULESZA