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

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  • Chenhao Sun
  • Zhiqiang Guan
  • Zhongqiu Tong
  • Junmin Nan


Original languageEnglish
Article number2204083
Journal / PublicationAdvanced Energy Materials
Issue number15
Online published3 Mar 2023
Publication statusPublished - 20 Apr 2023



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. © 2023 Wiley-VCH GmbH

Research Area(s)

  • COF separators, dendrite free, fast ion transport, sodium metal anodes, solid electrolyte interphase, ION BATTERIES, LITHIUM-ION, LI

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