Banca de DEFESA: JOÃO DE MEDEIROS DANTAS NETO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : JOÃO DE MEDEIROS DANTAS NETO
DATE: 22/04/2025
TIME: 09:00
LOCAL: Auditório da Física
TITLE:

 INFLUENCE OF SURFACE TREATMENTS ON TiNb2O7/Ni81Fe19 HETEROSTRUCTURES

KEY WORDS:

Lithium-ion batteries, heterostructure, TiNb2O7

PAGES: 107
BIG AREA: Engenharias
AREA: Engenharia de Materiais e Metalúrgica
SUMMARY:

The global transition to renewable energy has gained momentum in recent decades,
driven by the urgency to reduce carbon emissions and dependence on fossil fuels. In this
scenario, energy storage systems play a fundamental role, with lithium-ion batteries (LIBs)
standing out as one of the most promising technologies. However, conventional graphite
anodes, widely used in these batteries, face significant limitations, which has driven the search
for alternative materials. Titanium niobate (TNO) emerges as a viable candidate, as it can be
synthesized relatively simply through a solid-state reaction between TiO₂ and Nb₂O₅. Despite
its advantages, TNO presents challenges that need to be overcome. A promising approach is the
combination of this material with nickel-iron (NiFe) alloys, along with techniques such as tape
casting for controlling electrode morphology and porosity. Additionally, surface treatments can
be applied to reduce roughness and uniformize the surface, facilitating the deposition of
ferromagnetic materials via magnetron sputtering and improving adhesion between the
substrate and thin film. This study investigates a TNO/NiFe heterostructure, produced by
combining tape casting and magnetron sputtering, with the objective of evaluating its potential
for LIB applications. The developed materials were characterized regarding their structural,
morphological, electrical, dielectric, and magnetic properties. The results of these samples
indicated a reduction in surface roughness by approximately 80%, leading to a decrease of about
90% in electrical resistance, which was reduced from 4.38 kΩ to 0.27 kΩ after polishing. The
magnetic properties were also influenced, with a notable decrease in saturation and coercive
fields, which was reduced from 13 Oe to 4 Oe as polishing was intensified. The results
demonstrate the success of polishing in improving the electrical and magnetic properties of the
heterostructure. The combination of tape casting with polishing proved to be an effective
approach for producing TNO substrates with potential applications in batteries. The integration
of LIB components with ferromagnetic layers aligns with recent research on the use of magnetic
fields in ionic dynamics, driving the development of advanced battery technologies.

COMMITTEE MEMBERS:
Presidente - 1474380 - MARCIO ASSOLIN CORREA
Interno - 1149564 - WILSON ACCHAR
Externo ao Programa - 3365252 - JOAO CARLOS ROCHA DE ARAUJO - UFRNExterno à Instituição - DANNIEL FERREIRA DE OLIVEIRA - UFPB