Bifunctional Solid-State Copolymer Electrolyte with Stabilized Interphase for High-Performance Lithium Metal Battery...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Solid-state polymer electrolytes (SPEs) are crucial for developing safe and durable lithium metal batteries (LMBs).
• The solid electrolyte interphase (SEI) plays a vital role in battery performance and longevity.
• Existing electrolytes often face challenges in conductivity, stability, and operating temperature range.

Purpose of the Study:

• To synthesize novel cross-linking vinyl ethylene carbonate and ionic liquid copolymers for use as SPEs in LMBs.
• To investigate the synergistic effects of poly(vinyl ethylene carbonate) (PVEC) and ionic liquid components on ion transport.
• To evaluate the electrochemical performance and wide-temperature operability of LMBs utilizing the developed SPEs.

Main Methods:

• In-situ polymerization was employed to synthesize the bifunctional copolymer electrolyte.
• The ionic conductivity was measured at 25°C.
• Electrochemical window, mechanical properties, non-combustibility, and interfacial compatibility were assessed.
• LiFePO4 batteries were assembled and tested for performance across a temperature range of 0 to 60°C.

Main Results:

• The synthesized SPE exhibited an ionic conductivity of 1.97×10⁻⁴ S/cm at 25°C.
• The electrolyte demonstrated a wide electrochemical window, superior mechanical properties, and non-combustibility.
• Excellent interfacial compatibility was observed between the SPE and battery components.
• Bifunctional copolymer-based LiFePO4 batteries operated effectively between 0°C and 60°C.

Conclusions:

• The developed bifunctional copolymer SPE offers a promising solution for safe and wide-temperature-range LMBs.
• The synergistic combination of PVEC and ionic liquid enhances Li+ transport and overall battery performance.
• These findings pave the way for advanced energy storage solutions with improved safety and durability.