Cation Vacancy-Boosted Lewis Acid-Base Interactions in a Polymer Electrolyte for High-Performance Lithium Metal...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Polymer electrolytes offer flexibility and safety but suffer from low ionic conductivity and lithium transference.
• Existing limitations hinder the practical application of polymer electrolytes in energy storage devices.

Purpose of the Study:

• To develop a novel polymer electrolyte with enhanced ionic conductivity and stability.
• To investigate the role of cation vacancies in two-dimensional clay nanosheets for improved lithium-ion transport.

Main Methods:

• Incorporation of two-dimensional clay nanosheets with cation vacancies into a poly(ethylene oxide)/poly(vinylidene fluoride-co-hexafluoropropylene) blend.
• Electrochemical characterization including ionic conductivity, transference number, and electrochemical stability window measurements.
• Fabrication and testing of lithium-ion coin and pouch cells using various cathode materials.

Main Results:

• Achieved high ionic conductivity (2.6 × 10^-3 S cm^-1) and a high Li⁺ transference number (0.77).
• Demonstrated a wide electrochemical stability window (4.9 V) and excellent cycling performance in LiFePO₄∥Li cells (145 mA h g^-1, 97.3% retention after 100 cycles).
• Exhibited superior safety features in pouch cells under mechanical stress tests.

Conclusions:

• Cation vacancies in clay nanosheets effectively enhance lithium-ion dissociation and transport in polymer electrolytes.
• The developed polymer electrolyte demonstrates potential for high-performance and safe lithium-ion batteries.
• The strategy offers a promising route for designing advanced solid-state electrolytes.