法拉第效率
铵
水溶液
离子
X射线光电子能谱
铁氰化物
无机化学
材料科学
普鲁士蓝
化学
化学工程
物理化学
电化学
有机化学
电极
工程类
作者
Haoxiang Yu,Jiaxi Xu,Chenchen Deng,Maoting Xia,Xikun Zhang,Jie Shu,Zhen‐Bo Wang
出处
期刊:ACS applied energy materials
[American Chemical Society]
日期:2021-09-06
卷期号:4 (9): 9594-9599
被引量:21
标识
DOI:10.1021/acsaem.1c01725
摘要
As a member of Prussian blue analogs, insoluble ferrocyanides encounter a problem wherein their initial Coulombic efficiencies are frequently higher than 100% when those values should be lower than 100% under normal circumstances. Herein, we study the topochemistry of NH4+ in Ni2Fe(CN)6 during the electrochemical reaction and meet the same problem. The initial Coulombic efficiency of Ni2Fe(CN)6 is as high as 122.9%. Our investigation from ex situ X-ray photoelectron spectroscopy analysis suggests that such case is due to the oxidization of ferricyanide ions. We thereby design a simple approach to solve this problem. After the treatment, the weird initial Coulombic efficiency of the as-prepared Ni2Fe(CN)6 electrode has changed to 95.9%, and even its electrochemical performance is improved. Briefly, its capacity retention is modified from 81.4 to 87.3% after 85 cycles, and the rate capacities of Ni2Fe(CN)6-R are higher than those of Ni2Fe(CN)6. Our work reveals the mechanism about the weird initial Coulombic efficiency of the as-prepared Ni2Fe(CN)6 electrode and provides a way to solve this problem.
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