High capacity surface route discharge at the potassium-O2 electrode
High capacity surface route discharge at the potassium-O2 electrode
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DOI：
10.1016/j.jelechem.2018.03.041
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发表时间：
2018-06-15
影响因子：
4.5
通讯作者：
Bruce, Peter G.
中科院分区：
文献类型：
--
作者：
Chen, Yuhui;Jovanov, Zarko P.;Bruce, Peter G.
非质子金属- o -2电池阴极的表面放电通常会导致非导电氧化物产物的表面钝化。这导致细胞容量低和细胞早期死亡。在这里，我们研究了钾- o -2电池中的阴极放电反应，并证明了表面放电并不局限于薄（< 10 nm）金属氧化物层的生长。电化学分析和原位拉曼光谱证实了阴极反应的产物是KO2和K2O2的组合，这取决于应用电位。使用低施主数溶剂乙腈，使我们能够直接探测表面路线。旋转环盘电极、电化学石英晶体微天平和扫描电子显微镜的表征清楚地表明，形成了厚的> 1匝产品层，远远超过了相关锂- o -2电池的可能。这些结果首次证明了金属o -2电池的高容量表面路线，并且这里揭示的见解对K-O-2电池的设计具有重要意义。
Discharge by a surface route at the cathode of an aprotic metal-O-2 battery typically results in surface passivation by the non-conducting oxide product. This leads to low capacity and early cell death. Here we investigate the cathode discharge reaction in the potassium-O-2 battery and demonstrate that discharge by a surface route is not limited to growth of thin (< 10 nm) metal oxide layers. Electrochemical analysis and in situ Raman spectroscopy confirmed that the product of the cathode reaction is a combination of KO2 and K2O2, depending on the applied potential. Use of the low donor number solvent, acetonitrile, allows us to directly probe the surface route. Rotating ring-disk electrode, electrochemical quartz crystal microbalance and scanning electron microscope characterisations clearly demonstrate the formation of a thick > 1 turn product layer, far in excess of that possible in the related lithium-O-2 battery. These results demonstrate a high-capacity surface route in a metal-O-2 battery for the first time and the insights revealed here have significant implications for the design of the K-O-2 battery.