过电位
氧烷
化学
锂(药物)
电化学
反应机理
旋转环盘电极
重量分析
催化作用
无机化学
化学工程
电极
物理化学
电催化剂
有机化学
物理
内分泌学
工程类
医学
量子力学
光谱学
出处
期刊:Meeting abstracts
日期:2019-09-01
卷期号:MA2019-02 (6): 532-532
标识
DOI:10.1149/ma2019-02/6/532
摘要
Non-aqueous lithium-oxygen (Li-O 2 ) batteries have attracted intensive research attentions owing to their potential to provide gravimetric energy density 3–5 times that of conventional Li-ion batteries. In-depth understandings of the reaction mechanisms during discharge and charge are the prerequisites for further advancement of the Li-O 2 technology. The ORR has been widely established to generate Li 2 O 2 by surface (electrochemical) or solution (chemical) pathway via manipulating the fate of superoxide intermediate (LiO 2 ). However, the reaction mechanism of the charging reaction in Li-O 2 batteries (OER, or Li 2 O 2 oxidation) is still under debates. In this study, we report a potential-dependent oxidation mechanism of Li 2 O 2 (charging mechanism) by examining the reaction intermediate species at a wide range of charging overpotential via thin-film rotating–ring disk electrode (RRDE) and synchrotron-based X-ray absorption near edge structure (XANES). To investigate the oxidation behavior of Li 2 O 2 at lower overpotential, we used ruthenium (Ru) as the model catalyst to control the charging potential. To make the amount of reactant comparable to that in regular Li-O 2 cells, we here employ thin-film RRDE by drop casting Valcun Carbon (VC) or VC supported Ru (Ru/VC) particles onto the glass carbon electrode (disk) to increase the total surface area, as shown in Figure 1. XANES further provides the chemical information of reaction intermediates and parasitic product that caused by the intermediates/discharge product. We will discuss potential-dependent charging reaction pathways and provide insights in the design strategy to achieve efficient Li-O 2 batteries. Acknowledgement This work is supported by two grants from Research Grants Council (RGC) of the Hong Kong Special Administrative Region, China, under No. C7051-17G and CUHK 14207517. Figure 1
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