Study on the Catalytic Activity of Noble Metal Nanoparticles on Reduced Graphene Oxide for Oxygen Evolution Reactions in Lithium鈥揂ir Batteries
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- 作者：Yo Sub Jeong ; Jin-Bum Park ; Hun-Gi Jung ; Jooho Kim ; Xiangyi Luo ; Jun Lu ; Larry Curtiss ; Khalil Amine ; Yang-Kook Sun ; Bruno Scrosati ; Yun Jung Lee
- 刊名：Nano Letters
- 出版年：2015
- 出版时间：July 8, 2015
- 年：2015
- 卷：15
- 期：7
- 页码：4261-4268
- 全文大小：492K
- ISSN：1530-6992
文摘
Among many challenges present in Li鈥揳ir 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鈥揳ir cell cathodes with LiCF<sub>3sub>SO<sub>3sub>鈥搕etra(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 Li<sub>2sub>O<sub>2sub> 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鈥揳ir cells while maintaining electrolyte stability.