Three-Dimensional Metal-Organic Framework@Cellulose Skeleton-Reinforced Composite Polymer Electrolyte for...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Solid-state lithium metal batteries (SSLMBs) are crucial for high-energy-density applications.
• Composite polymer electrolytes (CPEs) offer a promising solution to overcome limitations of single-component solid electrolytes.
• Developing robust and efficient CPEs is key to advancing SSLMB technology.

Purpose of the Study:

• To create reinforced CPEs by combining a rigid functional skeleton with a soft polymer electrolyte.
• To investigate the synergistic effects of zeolitic imidazolate frameworks (ZIFs) and succinonitrile (SN) plasticizer on poly(ethylene oxide) (PEO) properties.
• To understand the lithium-ion conduction mechanism in the developed CPEs using computational methods.

Main Methods:

• Fabrication of ZIF-67@CF/PEO-SN CPEs via in situ growth of ZIFs on a cellulose fiber skeleton.
• Characterization of physical and electrochemical properties, including ionic conductivity, transference number, and electrochemical window.
• Assessment of mechanical strength and lithium plating/stripping stability.
• Density functional theory (DFT) calculations to study Li+ conduction mechanisms.

Main Results:

• The ZIF-67@CF/PEO-SN CPEs exhibited high ionic conductivity (1.17 × 10⁻⁴ S cm⁻¹ at 30 °C) and a Li+ transference number of 0.40.
• A wide electrochemical window of 5.0 V and notable tensile strength (18.7 MPa) were achieved.
• Superior lithium plating/stripping stability (>550 h) and excellent performance in LiFePO4/CPE/Li cells were demonstrated.

Conclusions:

• The synergistic combination of ZIF-67@CF and SN significantly enhances the properties of PEO-based CPEs.
• The developed CPEs show great potential for high-safety and high-energy-density SSLMBs.
• This research provides valuable insights for designing advanced functionalized CPEs for next-generation batteries.