Gel Polymer Electrolyte Membranes via Slit-Coating Technology for High-Energy Lithium Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Conventional lithium-ion batteries face safety challenges due to flammable liquid electrolytes.
• Solid polymer electrolytes often suffer from low ionic conductivity at room temperature, hindering high-energy battery development.

Purpose of the Study:

• To create a safer, high-performance gel polymer electrolyte (GPE) for lithium batteries.
• To enhance ion transport and interfacial properties of GPEs using inorganic ceramic fillers.

Main Methods:

• Flexible poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)-based GPE membranes were fabricated using slit-coating and UV curing.
• NASICON-type Li_1.3Al_0.3Ti_1.7P₃O₁₂ (LATP) and garnet-type Li_6.4La₃Zr_1.4Ta_0.6O₁₂ (LLZTO) were incorporated as ceramic fillers.
• Electrochemical performance, including ionic conductivity, transference number, and cycling stability, was evaluated.

Main Results:

• The PVDF-HFP GPE with 10 wt% LLZTO showed the highest ionic conductivity (3.40 × 10^-4 S·cm^-1) and Li⁺ transference number (0.77) at ambient temperature.
• LLZTO incorporation improved electrochemical reversibility, interfacial stability, mechanical strength, and flame-retardant properties.
• A LiFePO₄/GPE/Li cell demonstrated good rate capability (160 mAh·g^-1 at 0.1 C, 80 mAh·g^-1 at 1 C) and excellent cycling stability (96% retention after 100 cycles).

Conclusions:

• The LLZTO-modified PVDF-HFP GPE offers a promising strategy for developing safer and more efficient lithium batteries.
• This approach enables scalable preparation of high-performance electrolyte membranes for advanced energy storage solutions.