Dense PVDF-type polymer-in-ceramic electrolytes for solid state lithium batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• Developing stable and conductive solid electrolytes is crucial for next-generation lithium batteries.
• Composite electrolytes offer a promising route to combine the advantages of ceramic and polymer materials.

Purpose of the Study:

• To develop novel composite electrolytes based on LLZTO and PVDF with high ceramic content.
• To investigate the effect of hot pressing on the microstructure and electrochemical properties of the composite electrolytes.
• To evaluate the performance of the composite electrolytes in lithium metal batteries.

Main Methods:

• Fabrication of Li₇La₃Zr_1.4Ta_0.6O₁₂ (LLZTO) and polyvinylidene fluoride (PVDF) composite electrolytes (LPCEs) with up to 80 wt% ceramic loading.
• Hot pressing treatment to reduce porosity and enhance ionic conductivity.
• Electrochemical testing, including Li plating/stripping cycling and LiFePO₄/LPCE/Li cell performance evaluation.

Main Results:

• Achieved high ceramic content (up to 80 wt%) in LPCEs.
• Hot pressing significantly reduced porosity and increased ionic conductivity to 1.08 × 10^-4 S cm^-1 at 60 °C.
• Demonstrated stable Li plating/stripping cycling for over 1500 hours.
• Achieved 86% capacity retention over 200 cycles in a LiFePO₄/LPCE/Li cell.

Conclusions:

• Hot-pressed LLZTO/PVDF composite electrolytes exhibit enhanced ionic conductivity and electrochemical stability.
• The developed LPCEs are suitable for high-performance and long-cycle-life lithium metal batteries.
• High ceramic content composites are a viable strategy for advanced solid-state electrolytes.