Banca de DEFESA: Luana Sousa de Oliveira
Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.STUDENT : Luana Sousa de Oliveira
DATE: 08/03/2024
TIME: 14:00
LOCAL: CEFET-MG, Campus VI
TITLE:
Electrochemical performance of composite electrodes based on Ce-UiO66/MWCNT for supercapacitors application
KEY WORDS:
Supercapacitors, metal-organic frameworks, carbon nanotubes, redox electrolyte
PAGES: 113
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Físico-Química
SPECIALTY: Eletroquímica
SUMMARY:
The more efficient use of energy resources in order to reduce the world's dependence on non-renewable primary energy makes it necessary to invest in renewable energy sources. The research and development of efficient electrochemical energy storage systems is an important part of this step. Supercapacitors (SCs) have been extensively studied as energy storage devices due to their high power density and high cyclability.
Although they were originally used for applications that require fast pulses of energy, improvements that increase the energy density of supercapacitors is a strategic issue in this field of research, which allows expanding its niche of applications such as hybrid electric vehicles, power supplies portable devices, pulsed electronic devices, among others.
With the combination of faradaic and electrical double layer mechanisms, it is possible to obtain hybrid SCs that increase the energy density of cells to the level of batteries. These devices can be built using mainly faradaic/capacitive electrodes, pseudocapacitive materials and electrolytes containing redox additives.
The individual properties of the electrode and electrolyte materials influence the performance of a supercapacitor. Thus, the scientific community has been researching materials that have greater electrochemical stability, such as metal-organic frameworks (MOFs). Due to their high specific surface area (> 1000 m2g-1) they have been considered promising for the preparation of SC electrodes, despite MOFs having low electrical conductivity values. This limitation can be overcome by preparing composites with conductive materials such as graphene, carbon nanotubes, among others. Redox electrolytes are active species capable of electrosorbing and transferring electrons at the electrode/electrolyte interface and have been efficiently used to increase the performance of supercapacitors, mainly with regard to capacitance and energy density.
In the present work, the electrochemical performance of Ce-UiO66/multi-walled carbon nanotube (MWCNT) composite electrodes immersed in H2SO4 aqueous electrolyte containing cerium IV sulfate as redox species was evaluated. The results demonstrate that the electrode is stable in a wide range of potentials, supporting the high potential at which the redox reaction of the Ce3+/Ce4+ pair occurs (~1.2 V vs. Ag/AgCl/3.5M KCl). Under these conditions, high values of specific capacitance (380 F g-1) and energy density (155 kW g-1) were obtained.
COMMITTEE MEMBERS:
Presidente - JOAO PAULO CAMPOS TRIGUEIRO
Interna - RAQUEL VIEIRA MAMBRINI
Externo ao Programa - FLAVIO SANTOS FREITAS
Externo à Instituição - TULIO MATENCIO - UFMG