Cyclopropenium Cationic-Based Covalent Organic Polymer-Enhanced Poly(ethylene oxide) Composite Polymer Electrolyte...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Solid-state polymer electrolytes are crucial for advanced battery technologies.
• Lithium-sulfur (Li-S) batteries offer high theoretical energy density but face challenges in stability and cycling.
• Developing robust solid electrolytes is key to unlocking the potential of Li-S batteries.

Purpose of the Study:

• To synthesize a cyclopropenium cationic-based covalent organic polymer (iCP@TFSI) as a filler for polymer electrolytes.
• To investigate the impact of iCP@TFSI on the properties of polyethylene oxide (PEO)/LiTFSI solid-state polymer electrolytes.
• To evaluate the performance of all-solid-state Li-S batteries utilizing these enhanced electrolytes.

Main Methods:

• SN2 reaction and ion replacement for iCP@TFSI synthesis.
• Incorporation of iCP@TFSI into a PEO/LiTFSI matrix.
• Fabrication and electrochemical testing of all-solid-state Li-S batteries and symmetrical lithium cells.

Main Results:

• The PEO-10%iCP@TFSI electrolyte achieved an ionic conductivity of 1.2 × 10⁻³ S·cm⁻¹ at 80 °C.
• Enhanced mechanical properties and lithium metal anode stability were observed.
• Symmetrical lithium cells demonstrated over 600 hours of stable cycling.
• Li-S batteries exhibited a capacity retention of 490 mAh·g⁻¹ after 500 cycles at 1 C with near 100% Coulombic efficiency.

Conclusions:

• iCP@TFSI significantly improves ionic conductivity and mechanical properties of solid-state polymer electrolytes.
• The enhanced electrolytes lead to improved cycling stability and Coulombic efficiency in all-solid-state Li-S batteries.
• This work presents a promising strategy for developing high-performance solid-state batteries.