Dendrite-Free Sodium Metal Anodes Via Solid Electrolyte Interphase Engineering With a Covalent Organic Framework Separator,Advanced Energy Materials

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Dendrite-Free Sodium Metal Anodes Via Solid Electrolyte Interphase Engineering With a Covalent Organic Framework Separator
Advanced Energy Materials ( IF 24.4 ) Pub Date : 2023-03-03 , DOI: 10.1002/aenm.202204083
Tianxing Kang ₁ , Chenhao Sun ₂ , Yang Li ₁ , Tianyi Song ₁ , Zhiqiang Guan ₁ , Zhongqiu Tong _{1,

3} , Junmin Nan ₂ , Chun‐Sing Lee ₁

Affiliation

Solid electrolyte interphases (SEIs) play a crucial role in keeping sodium metal anodes (SMAs) intact and improving battery life. However, the SEIs arising from irreversible reactions between metallic Na and electrolytes fail to suppress Na dendrite growth and have sluggish Na⁺ kinetics. Herein, a functionalized separator modified by a sp² carbon conjugated-covalent organic framework (sp²c-COF) is proposed to induce a robust SEI. X-ray photoelectron spectroscopy (XPS) analyses and theoretical calculations demonstrate that the SEI is rich in NaF because the structure of NaPF₆ is unstable due to influences from the COF separator. In situ observations show that the Na dendrite is effectively suppressed even at a high current density of 20 mA cm⁻². Satisfactorily, the COF separator exhibits a high transference number of 0.78, achieving a fast Na plating/stripping process. Based on these superiorities, a symmetric cell Na|COF|Na shows stable cycling for over 1500 h at 20 mA cm⁻². In addition, full cells Na|COF|NaTi₂(PO₄)₃ (NTPO) present good rate performance (30 and 50 C) and excellent cycling stability over 5000 cycles at 5 and 10 C. The application of COFs to improve SMAs in this work demonstrates a new strategy for improving sodium metal batteries.

中文翻译：

通过具有共价有机骨架分离器的固体电解质界面工程实现无枝晶钠金属阳极

固体电解质中间相 (SEI) 在保持钠金属阳极 (SMA) 完好无损和延长电池寿命方面起着至关重要的作用。然而，由金属 Na 和电解质之间的不可逆反应产生的 SEI 不能抑制 Na 枝晶的生长并且具有缓慢的 Na ⁺动力学。在此，提出了一种由 sp ²碳共轭共价有机骨架 (sp ^{2 c-COF) 改性的功能化隔膜，以诱导稳健的 SEI。}X射线光电子能谱（XPS）分析和理论计算表明SEI富含NaF，因为NaPF _6的结构由于 COF 分离器的影响而不稳定。原位观察表明，即使在 20 mA cm ^-2的高电流密度下，Na 枝晶也能得到有效抑制。令人满意的是，COF 隔膜具有 0.78 的高转移数，实现了快速的 Na 电镀/剥离过程。基于这些优势，对称电池 Na|COF|Na 在 20 mA cm ^-2下显示出超过 1500 小时的稳定循环。此外，全电池 Na|COF|NaTi ₂ (PO ₄ ) ₃ (NTPO) 具有良好的倍率性能（30 和 50 C）和在 5 和 10 C 下超过 5000 个循环的出色循环稳定性。这项工作展示了一种改进钠金属电池的新策略。

更新日期：2023-03-03

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