Operando pH Measurements Decipher H+/Zn2+ Intercalation Chemistry in High-Performance Aqueous Zn/δ-V2O5 Batteries,ACS Energy Letters

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Operando pH Measurements Decipher H+/Zn2+ Intercalation Chemistry in High-Performance Aqueous Zn/δ-V2O5 Batteries
ACS Energy Letters ( IF 19.3 ) Pub Date : 2020-09-01 , DOI: 10.1021/acsenergylett.0c01767
Xu Liu _{1,

2} , Holger Euchner ₁ , Maider Zarrabeitia _{1,

2,

3} , Xinpei Gao _{1,

2} , Giuseppe Antonio Elia _{1,

2} , Axel Groß _{1,

4} , Stefano Passerini _{1,

2}

Affiliation

Vanadium oxides have been recognized to be among the most promising positive electrode materials for aqueous zinc metal batteries (AZMBs). However, their underlying intercalation mechanisms are still vigorously debated. To shed light on the intercalation mechanisms, high-performance δ-V₂O₅ is investigated as a model compound. Its structural and electrochemical behaviors in the designed cells with three different electrolytes, i.e., 3 m Zn(CF₃SO₃)₂/water, 0.01 M H₂SO₄/water, and 1 M Zn(CF₃SO₃)₂/acetonitrile, demonstrate that the conventional structural and elemental characterization methods cannot adequately clarify the separate roles of H⁺ and Zn²⁺ intercalations in the Zn(CF₃SO₃)₂/water electrolyte. Thus, an operando pH determination method is developed and used toward Zn/δ-V₂O₅ AZMBs. This method indicates the intercalation of both H⁺ and Zn²⁺ into δ-V₂O₅ and uncovers an unusual H⁺/Zn²⁺-exchange intercalation–deintercalation mechanism. Density functional theory calculations further reveal that the H⁺/Zn²⁺ intercalation chemistry is a consequence of the variation of the electrochemical potential of Zn²⁺ and H⁺ during the electrochemical intercalation/release.

中文翻译：

操作 pH 测量破译高性能水系 Zn/δ-V2O5 电池中的 H+/Zn2+ 嵌入化学

钒氧化物已被认为是最有前途的水系锌金属电池（AZMB）正极材料之一。然而，它们潜在的嵌入机制仍在激烈争论中。为了阐明嵌入机制，我们研究了高性能 δ-V ₂ O ₅作为模型化合物。其在设计的具有三种不同电解质的电池中的结构和电化学行为，即3 m Zn(CF ₃ SO ₃ ) ₂ /水、0.01 MH ₂ SO ₄ /水和1 M Zn(CF ₃ SO ₃ ) ₂/乙腈，证明常规的结构和元素表征方法不能充分阐明H ⁺和Zn ²⁺插层在Zn(CF ₃ SO ₃ ) ₂ /水电解质中的不同作用。因此，针对 Zn/δ-V ₂ O ₅AZMB开发并使用了一种操作 pH 测定方法。该方法表明 H ⁺和 Zn ²⁺都嵌入到 δ-V ₂ O ₅中，并揭示了一个不寻常的 H ⁺ /Zn ²⁺-交换嵌入-脱嵌机制。密度泛函理论计算进一步揭示了H ⁺ /Zn ²⁺嵌入化学是电化学嵌入/释放过程中Zn ²⁺和H ⁺的电化学电位变化的结果。

更新日期：2020-09-11

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