Steering Yolk-Shell Nanostructures of 1D Unit-Based Covalent Organic Frameworks as Binder Modulators
Yiwen Yang1, Fengxue Duan1, Xiaoman Yao1
1Guangdong Provincial Key Laboratory of Carbon Dioxide Resource Utilization, School of Chemistry, South China Normal University, Guangzhou, 510006, P. R. China.
Advanced Materials (Deerfield Beach, Fla.)
|May 16, 2025
Summary
Novel 1D covalent organic frameworks (1D COFs) with engineered nanostructures enhance lithium-sulfur battery performance. Yolk-shell COFs significantly boost capacity and cycling stability compared to hollow, solid, or traditional binders.
Area of Science:
- Materials Science
- Electrochemistry
- Nanotechnology
Background:
- 1D unit-based covalent organic frameworks (1D COFs) show promise for molecular assembly due to weak chain interactions.
- Exploration of 1D COFs in morphology engineering and energy storage applications, particularly for lithium-sulfur (Li-S) batteries, remains limited.
Purpose of the Study:
- To engineer diverse 1D COF nanostructures (yolk-shell, hollow, solid spheres) using a solvent-induced strategy.
- To evaluate these 1D COF nanostructures as binder modulators for improving Li-S battery performance.
- To investigate the role of nanomorphology and functional groups in enhancing electrochemical properties.
Main Methods:
- Solvent-induced synthesis of 1D COF nanostructures: yolk-shell spheres (YS-COF), hollow spheres (HS-COF), and solid spheres (SS-COF).
- Incorporation of 1D COFs as binder modulators in Li-S battery electrodes, replacing traditional polyvinylidene fluoride (PVDF).
- Electrochemical testing (specific capacity, cycling stability) and characterization.
- Density Functional Theory (DFT) calculations and finite element simulations.
Main Results:
- YS-COF, HS-COF, and SS-COF demonstrated improved mechanical properties, volume change adaptability, and lithium polysulfide (LiPSs) adsorption/catalysis compared to PVDF.
- The YS-COF-based Li-S battery exhibited a high initial specific capacity of 1011 mAh g⁻¹ at 0.5 C.
- YS-COF based cells maintained 962 mAh g⁻¹ at 4 C and cycled over 600 times.
- DFT and simulations confirmed the positive impact of YS-COF nanomorphology and functional groups on electrochemical kinetics.
Conclusions:
- Engineered 1D COF nanostructures, particularly yolk-shell spheres, significantly enhance Li-S battery performance by acting as effective binder modulators.
- The improved performance is attributed to enhanced mechanical stability, volume change accommodation, and superior LiPSs management.
- This morphology engineering strategy offers a promising pathway for optimizing 1D COFs in advanced energy storage systems.
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