An Advanced Gel Polymer Electrolyte for Solid-State Lithium Metal Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• All-solid-state lithium metal batteries (LMBs) are crucial for advanced energy storage.
• Solid electrolytes and interface compatibility are key determinants of LMB performance.
• Existing electrolytes often face challenges in mechanical strength, flexibility, and safety.

Purpose of the Study:

• To develop a high-performance gel polymer electrolyte (GPE) for LMBs.
• To enhance mechanical properties, ionic conductivity, and safety through a functional superposition strategy.
• To investigate the electrochemical performance and cycling stability of LMBs using the novel electrolyte.

Main Methods:

• Synthesized an advanced poly(vinylidene fluoride-hexafluoropropylene) based GPE (AP-GPEs).
• Incorporated butyl acrylate and polyethylene glycol diacrylate for elasticity.
• Added triethyl phosphate and fluoroethylene carbonate as flameproof plasticizers.
• Integrated Li$_{7}$La$_{3}$Zr$_{2}$O$_{12}$ nanowires (LLZO-w) as ion-conductive fillers.

Main Results:

• The AP-GPEs/LLZO-w membrane exhibited high mechanical strength and flexibility.
• Achieved low flammability and low activation energy (0.137 eV).
• Improved ionic conductivity (0.42 × 10$^{-3}$ S cm$^{-1}$ at 20 °C) due to continuous pathways.
• Demonstrated good safety and compatibility with lithium anodes.
• LiFePO$_{4}$/Li batteries showed 87.3% capacity retention after 600 cycles at 1 C and 93.3 mAh g$^{-1}$ at 5 C.

Conclusions:

• The functional superposition strategy effectively created a high-performance GPE.
• The AP-GPEs/LLZO-w membrane offers a promising solution for safer and more efficient LMBs.
• This approach advances the development of next-generation solid-state batteries.