title: Study on the Catalytic Activity of Noble Metal Nanoparticles on Reduced Graphene Oxide for Oxygen Evolution Reactions in Lithium-Air Batteries.
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 nanoparticles 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 nanoparticles 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 nanoparticles in lowering charge overpotential is to control the nature of the discharge products. Ru nanoparticles 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.
authors.affiliation: †Department of Energy Engineering, Hanyang University, Seoul 133-791, Republic of Korea.
authors.forename: Yo Sub
authors.initials: YS
authors.lastname: Jeong
authors.affiliation: †Department of Energy Engineering, Hanyang University, Seoul 133-791, Republic of Korea.
authors.forename: Jin-Bum
authors.initials: JB
authors.lastname: Park
authors.affiliation: †Department of Energy Engineering, Hanyang University, Seoul 133-791, Republic of Korea.|‡Department of Chemical Engineering, Hanyang University, Seoul 133-791, Republic of Korea.
authors.forename: Hun-Gi
authors.initials: HG
authors.lastname: Jung
authors.affiliation: †Department of Energy Engineering, Hanyang University, Seoul 133-791, Republic of Korea.
authors.forename: Jooho
authors.initials: J
authors.lastname: Kim
authors.affiliation: §Chemical Science and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States.
authors.forename: Xiangyi
authors.initials: X
authors.lastname: Luo
authors.affiliation: §Chemical Science and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States.
authors.forename: Jun
authors.initials: J
authors.lastname: Lu
authors.affiliation: ∥Material Sciences Division, Argonne National Laboratory, Argonne, Illinois 60439, United States.
authors.forename: Larry
authors.initials: L
authors.lastname: Curtiss
authors.affiliation: §Chemical Science and Engineering Division, Argonne National Laboratory, Argonne, Illinois 60439, United States.
authors.forename: Khalil
authors.initials: K
authors.lastname: Amine
authors.affiliation: †Department of Energy Engineering, Hanyang University, Seoul 133-791, Republic of Korea.
authors.forename: Yang-Kook
authors.initials: YK
authors.lastname: Sun
authors.affiliation: ⊥Italian Institute of Technology, 16163 Genoa, Italy.
authors.forename: Bruno
authors.initials: B
authors.lastname: Scrosati
authors.affiliation: †Department of Energy Engineering, Hanyang University, Seoul 133-791, Republic of Korea.
authors.forename: Yun Jung
authors.initials: YJ
authors.lastname: Lee
keywords: catalysts; catalytic mechanism; electrolyte stability; lithium−air batteries; noble metals