Study on the Catalytic Activity of Noble Metal Nanoparticles on Reduced Graphene Oxide for Oxygen Evolution Reactions in Lithium-Air Batteries

Title
Study on the Catalytic Activity of Noble Metal Nanoparticles on Reduced Graphene Oxide for Oxygen Evolution Reactions in Lithium-Air Batteries
Author
선양국
Keywords
lithium-air batteries; catalysts; noble metals; electrolyte stability; catalytic mechanism
Issue Date
2015-07
Publisher
AMER CHEMICAL SOC
Citation
NANO LETTERS, v. 15, NO 7, Page. 4261-4268
Abstract
Among many challenges present in Li-air batteries, one of the main reasons of low efficiency is the high charge overpotential due to the slow oxygen evolution reaction (OER). Here, we present systematic evaluation of Pt, Pd, and Ru nanopartides supported on rGO as OER electrocatalysts in Li-air cell cathodes with LiCF3SO3-tetra(ethylene glycol) dimethyl ether (TEGDME) salt-electrolyte system. All of the noble metals explored could lower the charge overpotentials, and among them, Ru-rGO hybrids exhibited the most stable cycling performance and the lowest charge overpotentials. Role of Ru nanopartides in boosting oxidation kinetics of the discharge products were investigated. Apparent behavior of Ru nanoparticles was different from the conventional electrocatalysts that lower activation barrier through electron transfer, because the major contribution of Ru nanopartides in lowering charge overpotential is to control the nature of the discharge products. Ru nanopartides facilitated thin film-like or nanoparticulate Li2O2 formation during oxygen reduction reaction (ORR), which decomposes at lower potentials during charge, although the conventional role as electrocatalysts during OER cannot be ruled out. Pt-and Pd-rGO hybrids showed fluctuating potential profiles during the cycling. Although Pt- and Pd-rGO decomposed the electrolyte after electrochemical cycling, no electrolyte instability was observed with Ru-rGO hybrids. This study provides the possibility of screening selective electrocatalysts for Li-air cells while maintaining electrolyte stability.
URI
http://pubs.acs.org/doi/abs/10.1021/nl504425hhttp://hdl.handle.net/20.500.11754/26410
ISSN
1530-6984; 1530-6992
DOI
10.1021/nl504425h
Appears in Collections:
COLLEGE OF ENGINEERING[S](공과대학) > ENERGY ENGINEERING(에너지공학과) > Articles
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