Tailored Solid Polymer Electrolytes by Montmorillonite with High Ionic Conductivity for Lithium-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Polyethylene oxide (PEO)-based solid polymer electrolytes (SPEs) are crucial for next-generation lithium-ion batteries.
• A key limitation is the low ionic conductivity due to strong coordination between lithium ions and PEO chains.

Purpose of the Study:

• To enhance the ionic conductivity of PEO-based SPEs.
• To investigate the effect of incorporating montmorillonite (MMT) as a Lewis base center.

Main Methods:

• Incorporation of sub-micron montmorillonite into PEO polymer frames.
• Electrochemical testing of SPEs and LiFePO4 batteries at various temperatures and rates.

Main Results:

• Montmorillonite addition significantly improved ionic conductivity to 4.7 mS cm⁻¹ at 70°C, comparable to liquid electrolytes.
• Batteries utilizing MMT-enhanced SPEs coupled with LiFePO4 exhibited high discharge capacity (150.3 mAh g⁻¹) and excellent rate performance.

Conclusions:

• Montmorillonite acts as an effective Lewis base, reducing lithium ion-PEO chain coordination and enhancing conductivity.
• Customized incorporation of Lewis base materials presents a promising strategy for high-performance PEO-based solid-state electrolytes.