无水和羟基化的CuF2纳米粒子的新型合成及其锂离子电池的潜力,Chemistry - A European Journal

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无水和羟基化的CuF2纳米粒子的新型合成及其锂离子电池的潜力
Chemistry - A European Journal ( IF 3.9 ) Pub Date : 2018-04-18 , DOI: 10.1002/chem.201800207
Thoralf Krahl _{1,

2} , Friederike Marroquin Winkelmann ₁ , Andréa Martin ₁ , Nicola Pinna _{1,

3} , Erhard Kemnitz _{1,

2}

Affiliation

无水纳米CuF ₂是由醇盐Cu（OR）₂（R = Me，t Bu）通过在纯液态HF中于-70°C或在溶剂热条件下于150°C使用过量的HF和THF作为溶剂的反应合成的。取决于合成方法，获得尺寸在10至100nm之间的纳米颗粒。所述化合物是高度吸湿的，并在潮湿的空气中形成不同的水解产物，即CUF ₂⋅ 2小时₂ O，的Cu ₂（OH）的F ₃和Cu（OH）F，其中只有后者在室温下是稳定的。铜₂与半电池锂离子电池中的锂相比，当循环时，锂在〜2.7 V的电势下表现出电化学平稳期，这归因于不可逆转换机制。在第一个循环中，电池容量取决于颗粒大小，≈8nm的微晶直径为468 mAh g ^-1，≈12nm的微晶直径为353 mAh g ^-1，称为CuF ₂。然而，如此高的容量不能维持几个周期，并且容量迅速消失。电池电压降低至≈2.0V代表CUF ₂⋅ 2小时₂ O，的Cu ₂（OH）的F ₃和Cu（OH）F。由于这项工作中研究的所有化合物均显示出不可逆的转化反应，因此可以得出结论，铜基氟化物不适合锂离子电池应用。

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Novel Synthesis of Anhydrous and Hydroxylated CuF2 Nanoparticles and Their Potential for Lithium Ion Batteries

Anhydrous nanoscopic CuF₂ is synthesized from alkoxides Cu(OR)₂ (R=Me, tBu) by their reaction either in pure liquid HF at −70 °C, or under solvothermal conditions at 150 °C using excess HF and THF as solvent. Depending on the synthesis method, nanoparticles of sizes between 10 and 100 nm are obtained. The compound is highly hygroscopic and forms different hydrolysis products under moist air, namely CuF₂⋅2 H₂O, Cu₂(OH)F₃, and Cu(OH)F, of which only the latter is stable at room temperature. CuF₂ exhibits an electrochemical plateau at a potential of ≈2.7 V when cycled versus Li in half cell Li‐ion batteries, which is attributed to a non‐reversible conversion mechanism. The cell capacity in the first cycle depends on the particle size, being 468 mAh g⁻¹ for ≈8 nm crystallite diameter, and 353 mAh g⁻¹ for ≈12 nm crystallite diameter, referred to CuF₂. However, such a high capacity cannot be sustained for several cycles and the capacity rapidly fades out. The cell voltage decreases to ≈2.0 V for CuF₂⋅2 H₂O, Cu₂(OH)F₃, and Cu(OH)F. As all the compounds studied in this work show irreversible conversion reactions, it can be concluded that copper‐based fluorides are unsuitable for Li‐ion battery applications.

更新日期：2018-04-18

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