High-Performance Solid Polymer Electrolyte Constructed from Long-Chain Regulated Random Copolymers and Porous PI...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Solid polymer electrolytes (SPEs) offer high safety for energy storage but suffer from low ionic conductivity and poor mechanical strength at room temperature.
• Addressing the conductivity-mechanical property trade-off is crucial for developing advanced solid-state batteries.

Purpose of the Study:

• To develop a novel composite electrolyte by synergistically combining polymer microstructure regulation with a porous support.
• To enhance the ionic conductivity and mechanical stability of SPEs for high-performance energy storage applications.

Main Methods:

• Synthesis of a linear random copolyester, poly(1,3-propylene-co-1,4-butylene succinate-co-sebacate) (PBPSS), using specific diols and diacids.
• Preparation of the PBPSS-75 composite electrolyte using the synthesized copolyester and a porous polyimide (PI) support.
• Characterization of ionic conductivity, lithium-ion transference number, electrochemical stability window, and battery performance (LiFePO4//Li and Li symmetric cells).

Main Results:

• The long-carbon-chain sebacic acid in PBPSS effectively improved polymer segment flexibility and free volume.
• The PBPSS-75 composite electrolyte achieved an ionic conductivity of 4.25 × 10^-5 S cm^-1 at 30 °C, a transference number of 0.81, and an electrochemical stability window of 4.48 V.
• The composite electrolyte demonstrated excellent cycling stability in LiFePO4//Li batteries (100% capacity retention after 300 cycles) and lithium symmetric cells (over 800 h).

Conclusions:

• The synergistic strategy of long-carbon-chain polymer microstructure regulation and porous PI support effectively overcomes the limitations of SPEs.
• This approach significantly enhances both ionic conductivity and interfacial mechanical stability, paving the way for high-performance solid-state batteries.
• The study provides valuable theoretical and technical insights for designing advanced materials for solid-state energy storage.