Insights into the Chemical Nature and Formation Mechanisms of Discharge Products in Na–O2 Batteries by Means of Operando X-ray Diffraction
Insights into the Chemical Nature and Formation Mechanisms of Discharge Products in Na–O2 Batteries by Means of Operando X-ray Diffraction
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DOI：
10.1021/acs.jpcc.6b00903
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发表时间：
2016-04
影响因子：
3.7
通讯作者：
R. Pinedo;D. Weber;Benjamin J. Bergner;D. Schröder;P. Adelhelm;J. Janek
中科院分区：
文献类型：
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作者：
R. Pinedo;D. Weber;Benjamin J. Bergner;D. Schröder;P. Adelhelm;J. Janek
由于形成过氧化钠(Na2O2)或过氧化钠(NaO2)的看似相似的电池单元的电化学行为不同，非水Na-O2电池中放电产物的化学性质引起了人们的注意。放电过程中排他形成一种或另一种相的实验控制参数尚不清楚。本文用X-射线衍射仪证明了气相水分对产物化学性质的重要作用。对于碱-O2系统，操纵面X射线衍射很少被报道，但提供了关于电池中固体放电产物、生长/分解速率和副反应的有价值的实时信息。此外，对Na2O2·2H2O的放电/充电机制进行了详细的监测，证明了与形成NaO2和Li2O2的电池反应的重要区别，并驳斥了以前的错误结论。此外，还讨论了外加电势窗在循环过程中的作用，它为循环过程提供了有价值的信息。
The chemical nature of discharge products in nonaqueous Na–O2 batteries attracts attention due to the differing electrochemical behavior of seemingly similar battery cells forming either sodium peroxide (Na2O2) or sodium superoxide (NaO2). The experimental control parameters for the exclusive formation of one or the other phase during discharge are still unknown. In this paper, the important role of gas phase moisture on the chemical nature of these products is demonstrated by means of operando XRD. Operando XRD is rarely reported for alkali-O2 systems but provides valuable real time information about the solid discharge products, growth/decomposition rates, and side reactions in the cell. In addition, the discharge/charge mechanisms of Na2O2·2H2O are monitored in detail evidencing important differences from the cell reactions forming NaO2 and Li2O2 and refuting previous incorrect conclusions. Moreover, the effect of the applied potential window during cycling is discussed, as it provides valuable informa...