High Cyclability rGO/Pd/α-MnO2 Nanocomposite for Lithium-Air Battery Utilized As Air Breathing Cathode

Ahmed Al-Ogaili, Hatem Akbulut, Tugrul Cetinkaya

Research output: Contribution to conferenceAbstractScientificpeer-review

Abstract

Lithium-oxygen (Li-O 2) batteries have been developed as the next generation in energy storage due to their high theoretical energy densities (11,140 Wh / kg). Although, in the Li – O 2 battery, short cycle life, low energy efficiency, low charging / discharging rates are critical challenges . Cathode catalysts play a significant role in overcoming these limitations and promote oxygen reduction reaction and oxidation for Li- O 2 batteries. Therefore, designing a cathode with porous structure, highly conductive, good chemically stable and high catalytic activity is required. In this study, we focus on designing enhanced cathode air electrode to improve electrochemical performance of current lithium-oxygen batteries by utilizing high-efficiency nanocatalysts assembled by reduced graphene oxide (rGO) / Pd / α-MnO 2 nanocomposite. Among the carbon materials, graphene has a great potential to be used for energy storage due to its superior electronic conductivity, large theoretical surface area (2630 m 2 g −1), excellent structural flexibility and high surface area to volume ratio. rGO with noble Metals such as palladium have been explored as oxygen evolution reduction (OER) electrocatalysts in Li − air cells to lower the charge overpotentials and exhibit stable cycling performance. Additionally, MnO 2 is an attractive functional metal oxide as a catalyst for lithium air batteries due to its structural flexibility, low cost, high catalytic ability, high average voltage, and it is eco-friendly. rGO / Pd / α-MnO 2 nanocomposite cathode combines unique properties to enhance cyclability with elevated capacity at a high rate to obtain highly practical performance of Li – O 2 cells. Graphene oxide (GO) was prepared by modified hummers method, followed by deposition of Pd on the GO surface assure the strong interactions between cationic Pd 2+ and the oxygen functional groups (hydroxyl, epoxy and carboxyl groups) on the surface and edge of the GO sheets, which increase the surface area, avoiding aggregation of rGO and lead to enhance electrochemical performance. Afterward, α-MnO 2 nanowires, which are synthesized through the hydrothermal method, was anchored between as-prepared rGO @ Pd sheets by mechanical milling. The prepared samples were characterized by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS). Moreover, we indicate electrochemical performances of rGO @ Pd @ α-MnO 2 nanocomposites using ECC-Air test cell. Electrochemical cycling tests of the rGO @ Pd @ α-MnO 2 nanocomposite cathodes were carried out in the voltage range of 1.5 V to 4.5 V at a constant current density of 0.1 mA / cm 2. For further electrochemical characterization, EIS spectroscopy measurements were perfromed in the frequencies range of 100 kHz to 0.1 Hz. Moreover, in order to study lithium oxide formation and decomposition reactions, cyclic voltammetry test was performed at a scan rate of 0.5 mV/s.
Original languageEnglish
DOIs
Publication statusPublished - 1 Oct 2019
MoE publication typeNot Eligible
EventElectrochemistry Conference - Istanbul, Türkiye
Duration: 30 Sept 20192 Oct 2019
Conference number: 12

Conference

ConferenceElectrochemistry Conference
Abbreviated titleElectro Chem
Country/TerritoryTürkiye
CityIstanbul
Period30/09/201902/10/2019

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