Modified Polyethylene Oxide Solid-State Electrolytes with Poly(vinylidene fluoride-hexafluoropropylene)

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Lithium-ion batteries face limitations due to safety concerns with liquid electrolytes, including poor chemical stability and flammability.
• Solid electrolytes offer a promising alternative to enhance battery safety and performance.

Purpose of the Study:

• To improve the performance of polyethylene oxide (PEO)-based polymer electrolytes by blending them with poly(vinylidene fluoride-hexafluoropropylene) (P(VDF-HFP)).
• To investigate the effect of P(VDF-HFP) addition on the structural and electrochemical properties of PEO-based solid electrolytes.

Main Methods:

• Blending PEO with varying concentrations of P(VDF-HFP) to form polymer electrolyte membranes.
• Characterization of ionic conductivity, electrochemical window, thermal stability, and lithium-ion transference number.
• Fabrication and testing of lithium-ion cells using the developed solid electrolyte membranes.

Main Results:

• The addition of P(VDF-HFP) increased amorphous domains in PEO, facilitating lithium-ion migration.
• The optimal electrolyte membrane (30 wt% P(VDF-HFP)/70 wt% PEO) showed high ionic conductivity, a wide electrochemical window, and enhanced thermal stability.
• The optimized solid electrolyte exhibited a high lithium-ion transference number of 0.45.
• Cells demonstrated excellent rate performance and cycling stability, retaining high specific capacities after 200 cycles.

Conclusions:

• Blending PEO with P(VDF-HFP) effectively enhances the properties of solid polymer electrolytes for lithium-ion batteries.
• The developed solid electrolyte shows significant potential for safe and high-performance lithium-ion battery applications.
• This approach offers a viable strategy for overcoming the safety challenges associated with conventional liquid electrolytes.