Lithium-Ion Battery Solid Electrolytes Based on Poly(vinylidene Fluoride)-Metal Thiocyanate Ionic Liquid Blends

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Solid polymer electrolytes (SPEs) are crucial for enhancing battery safety by replacing liquid electrolytes.
• Developing safe and efficient SPEs is key for next-generation energy storage solutions.

Purpose of the Study:

• To develop and characterize a hybrid SPE based on poly(vinylidene fluoride) (PVDF) and a magnetic ionic liquid (MIL).
• To investigate the room-temperature battery cycling behavior of the developed hybrid SPE.

Main Methods:

• Solvent casting was used to prepare PVDF-MIL composite SPEs with varying MIL content (up to 40 wt %).
• Material properties including morphology, phase, crystallinity, thermal stability, and mechanical strength were analyzed.
• Ionic conductivity was measured at different temperatures.
• Electrochemical performance was evaluated using cathodic half-cells at room temperature.

Main Results:

• The hybrid SPE maintained a compact morphology and showed increased polar β-phase PVDF with higher MIL content.
• Ionic conductivity increased with temperature and MIL content, reaching 7 × 10^-4 mS cm^-1 at room temperature for 40 wt % MIL.
• The SPE exhibited good reversibility and cycling stability, achieving 80 mAh g^-1 at C/10 with 99% Coulombic efficiency.

Conclusions:

• The developed magnetic SPE shows promising performance for sustainable lithium-ion batteries.
• The material's properties and performance can be further enhanced by applying an external magnetic field.