Forschungszentrum Jülich, Institut für Energie- und Klimaforschung, IEK-9, 52452 Jülich, Germany.
ChemSusChem. 2012 Nov;5(11):2278-85. doi: 10.1002/cssc.201200199. Epub 2012 Oct 2.
The electrocatalytical process at the air cathode in novel silicon-air batteries using the room-temperature ionic liquid hydrophilic 1-ethyl-3-methylimidazolium oligofluorohydrogenate [EMI⋅2.3 HF⋅F] as electrolyte and highly doped silicon wafers as anodes is investigated by electrochemical means, X-ray photoelectron spectroscopy (XPS), and electron paramagnetic resonance (EPR) spectroscopy. The results obtained by XPS and EPR provide a model to describe the limited discharge capacity by means of a mechanism of air-electrode deactivation. In that respect, upon discharge the silicon-air battery's cathode is not only blocked by silicon oxide reduction products, but also experiences a major modification in the MnO₂ catalyst nature. The proposed modification of the MnO₂ catalyst by means of a MnF₂ surface layer greatly impacts the Si-air performance and describes a mechanism relevant for other metal-air batteries, such as the lithium-air. Moreover, the ability for this deactivation layer to form is greatly impacted by water in the electrolyte.
用电化学方法、X 射线光电子能谱（XPS）和电子顺磁共振（EPR）光谱研究了新型硅空气电池中空气阴极的电催化过程，该电池使用室温离子液体亲水性 1-乙基-3-甲基咪唑低氟化氢盐[EMI ⋅ 2.3 HF ⋅ F]作为电解质，高掺杂硅片作为阳极。XPS 和 EPR 的结果提供了一个通过空气电极失活机制来描述有限放电容量的模型。在这方面，在放电过程中，硅空气电池的阴极不仅被硅氧化物还原产物堵塞，而且 MnO₂催化剂的性质也发生了重大变化。通过 MnF₂表面层对 MnO₂催化剂的这种改性极大地影响了 Si-空气性能，并描述了一种与其他金属空气电池（如锂空气电池）相关的机制。此外，电解质中水分对失活层形成能力的影响很大。
