Inspired by the Cu-driven conversion reaction: how anionic properties dictate the electrochemical performance of vanadium sulfide,Journal of Materials Chemistry A

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Inspired by the Cu-driven conversion reaction: how anionic properties dictate the electrochemical performance of vanadium sulfide
Journal of Materials Chemistry A ( IF 10.7 ) Pub Date : 2022-11-18 , DOI: 10.1039/d2ta07832e
Wenjuan Yang ₁ , Kaihong Wang ₁ , Wenbo Zhou ₁ , Ningjing Luo ₁ , Shuping Huang ₁ , Yafeng Li ₁ , Kwun Nam Hui ₂ , Mingdeng Wei ₁

Affiliation

The so-called “activation process” of the VS₂/SNC anode in sodium-ion batteries actually results from the Cu current collector-involved electrochemical reactions. Metallic Cu with a strong sulfiphilic property endows the VS₂/SNC anode with a high reversible capacity of 586.9 mA h g⁻¹ even after 500 cycles, but only when using the electrolyte of 1.0 M NaPF₆ diglyme can such a favorable cycle stability be presented. Once the electrolyte of 1.0 M NaCF₃SO₃ diglyme is adopted, the device exhibits large overpotentials and its capacity decays dramatically. Examining the solvation structures and electrode/electrolyte interface properties, it is confirmed that the anionic property of the electrolyte plays a significant role in determining the electrochemical performance of metal sulfides. Triflate anions with a strong donicity not only aggravate the shuttle effect but also hinder the Na⁺ transport at the electrode/electrolyte interface, resulting in poor reversibility and sluggish kinetics of the anode, and such an interaction is intensified in Cu₂S due to the soft acceptor characteristics of Cu (I).

中文翻译：

受铜驱动转化反应的启发：阴离子特性如何决定硫化钒的电化学性能

钠离子电池中VS ₂ /SNC负极的所谓“活化过程”实际上是由Cu集电器参与的电化学反应引起的。具有强亲硫性的金属 Cu 赋予 VS ₂ /SNC 负极即使在 500 次循环后仍具有 586.9 mA hg ^-1的高可逆容量，但只有在使用 1.0 M NaPF ₆二甘醇二甲醚电解质时才能呈现出如此良好的循环稳定性. 一旦 1.0 M NaCF ₃ SO _{3的电解质}采用二甘醇二甲醚，器件表现出较大的过电位，容量急剧衰减。检查溶剂化结构和电极/电解质界面性质，证实电解质的阴离子性质在决定金属硫化物的电化学性能方面起着重要作用。具有强多西性的三氟甲磺酸阴离子不仅加剧了穿梭效应，而且阻碍了电极/电解质界面处的 Na ⁺传输，导致阳极的可逆性和动力学缓慢，并且这种相互作用在 Cu ₂ S 中得到加强，因为Cu ( I )的软受体特性。

更新日期：2022-11-18

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