Department of Engineering Physics, École Polytechnique de Montréal , Montreal, Quebec H3C 3A7, Canada.
ACS Appl Mater Interfaces. 2015 Dec 9;7(48):26387-90. doi: 10.1021/acsami.5b09430. Epub 2015 Nov 30.
Ion trapping under charge insertion-extraction is well-known to degrade the electrochemical performance of oxides. Galvanostatic treatment was recently shown capable to rejuvenate the oxide, but the detailed mechanism remained uncertain. Here we report on amorphous electrochromic (EC) WO3 thin films prepared by sputtering and electrochemically cycled in a lithium-containing electrolyte under conditions leading to severe loss of charge exchange capacity and optical modulation span. Time-of-flight elastic recoil detection analysis (ToF-ERDA) documented pronounced Li(+) trapping associated with the degradation of the EC properties and, importantly, that Li(+) detrapping, caused by a weak constant current drawn through the film for some time, could recover the original EC performance. Thus, ToF-ERDA provided direct and unambiguous evidence for Li(+) detrapping.
离子在充电-放电过程中的捕获会降低氧化物的电化学性能，这是众所周知的。最近的研究表明，恒电流处理能够使氧化物恢复活性，但详细的机制仍不确定。在这里，我们报告了通过溅射制备的非晶态电致变色（EC）WO3 薄膜，并在锂含量电解液中进行电化学循环，实验条件导致电荷交换容量和光学调制幅度严重损失。飞行时间弹性反冲探测分析（ToF-ERDA）记录到明显的 Li+捕获，这与 EC 性能的退化有关，重要的是，通过在薄膜上施加一段时间的弱恒流，可以使 Li+脱附，从而恢复原始的 EC 性能。因此，ToF-ERDA 提供了 Li+脱附的直接和明确的证据。
