Issue 3, 2024

Enhancing ionic conductivity and suppressing Li dendrite formation in lithium batteries using a vinylene-linked covalent organic framework solid polymer electrolyte

Abstract

The growing demand for energy-dense and safe batteries drives research towards all-solid-state lithium (Li) batteries. Existing poly(ethylene oxide) (PEO)-based solid polymer electrolytes (SPEs) suffer from low Li+ conductivity and Li dendrite penetration. Covalent organic frameworks (COFs) as highly crystalline, porous, and chemically diverse organic materials show great potential to address these problems. However, extensively studied imine-linked COFs show insufficient electrochemical stability against reactive Li metal, limiting their application for Li batteries. Herein, we develop a chemically stable vinylene-linked covalent organic framework (VCOF)-based SPE. By incorporating <4 wt% VCOF-1, a 25% improvement in ionic conductivity and a 46% increase in Li+ transference number at 60 °C are achieved. DFT calculations reveal that VCOF-1 facilitates Li+ transport through its cylindrical pores aided by PEO. In situ X-ray tomography confirms that VCOF-1 substantially suppresses Li dendrite growth in the VCOF-SPE-based Li metal batteries attributed to the enhanced Li-ion conduction and 12-fold improved mechanical strength. VCOF-SPEs also exhibit a high capacity of ∼145 mA h g−1 at 0.1C in LiFePO4|Li coin cells. Notably, the LiFePO4|Li pouch cell withstands abuse test conditions such as folding, cutting, and nail penetration. These results demonstrate the potential of VCOFs in future all-solid-state Li metal batteries for energy storage.

Graphical abstract: Enhancing ionic conductivity and suppressing Li dendrite formation in lithium batteries using a vinylene-linked covalent organic framework solid polymer electrolyte

Supplementary files

Article information

Article type
Paper
Submitted
12 Aug 2023
Accepted
04 Dec 2023
First published
05 Dec 2023
This article is Open Access
Creative Commons BY license

J. Mater. Chem. A, 2024,12, 1694-1702

Enhancing ionic conductivity and suppressing Li dendrite formation in lithium batteries using a vinylene-linked covalent organic framework solid polymer electrolyte

J. Yang, C. Lin, Y. Wang, Y. Xu, D. T. Pham, X. Meng, K. V. Tran, S. Cao, N. Kardjilov, A. Hilger, J. D. Epping, I. Manke, A. Thomas and Y. Lu, J. Mater. Chem. A, 2024, 12, 1694 DOI: 10.1039/D3TA04822E

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