Influence of Tetraalkylammonium Cation Chain Length on Gold and Glassy Carbon Electrode Interfaces for Alkali Metal-Oxygen Batteries
Influence of Tetraalkylammonium Cation Chain Length on Gold and Glassy Carbon Electrode Interfaces for Alkali Metal-Oxygen Batteries
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DOI：
10.1021/jz501850u
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发表时间：
2014-11-06
影响因子：
5.7
通讯作者：
Hardwick, Laurence J.
中科院分区：
文献类型：
--
作者：
Aldous, Iain M.;Hardwick, Laurence J.
与金属空气电池相关的双氧电化学的基础研究通常需要导电支持盐，如四烷基铵，以维持非水电解质中的氧化还原过程。电化学分析的形成和氧化的超氧化物在玻璃碳和金工作电极上已示出了减少的可逆性和降低的氧还原速率常数时，四烷基铵阳离子的烷基链长度增加。原位表面增强拉曼光谱（Sers）探测Au上的界面区域提供的证据表明，这是由四烷基铵阳离子在负电位下的吸附特性的变化引起的。这些影响随着较长的烷基链长度而增强，因此降低了超氧化物形成和双氧释放的可逆性。从这些观察结果可以确定，较短链的四烷基铵阳离子，同时保留必要的导电支持：（1）提高可逆性和超氧化物的形成和氧化的速率和（2）在原位Sers，具有较低的优先吸附，从而提高超氧化物在Au电极界面的实验检测。
Fundamental studies of dioxygen electrochemistry relevant to metal air batteries commonly require conductive supporting salts, such as tetraalkylammonium, to sustain redox processes in nonaqueous electrolytes. Electrochemical analysis of the formation and oxidation of superoxide on glassy carbon and gold working electrodes has shown a decrease in reversibility and lowering of the oxygen reduction rate constant when tetraalkylammonium cation alkyl chain length is increased. Probing interfacial regions on Au using in situ surface enhanced Raman spectroscopy (SERS) provides evidence that this is caused by the changing adsorption characteristics of tetralkylammonium cations under negative potentials. These effects are heightened with longer alkyl chain lengths, therefore reducing the reversibility of superoxide formation and dioxygen evolution. From these observations it can be established that shorter chain tetraalkylammonium cations while retaining necessary conductive support: (1) enhance reversibility and rate of superoxide formation and oxidation and (2) for in situ SERS, have lower preference for adsorption, thus improving experimental detection of superoxide at the Au electrode interface.