Highly Conductive PEO/PAN-Based SN-Containing Electrospun Membranes as Solid Polymer Electrolytes.

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Solid polymer electrolytes (SPEs) are crucial for developing safer all-solid-state batteries (ASSBs).
• Current SPEs face limitations in thermal stability and ionic conductivity, hindering widespread adoption.
• Electrospun polymer blends offer a promising route to overcome these challenges.

Purpose of the Study:

• To investigate the effect of polymer ratios and plasticizer concentration on the properties of electrospun (PAN/PEO)-LiBF4 solid polymer electrolytes.
• To optimize the composition for enhanced ionic conductivity and electrochemical performance in ASSBs.
• To elucidate the role of polymer immiscibility in facilitating ion transport.

Main Methods:

• Fabrication of electrospun polymer blend membranes using varying ratios of polyacrylonitrile (PAN) and polyethylene oxide (PEO).
• Incorporation of lithium bis(trifluoromethane sulfonyl)imide (LiTFSI) as a conductive salt and succinonitrile (SN) as a plasticizer.
• Characterization of ionic conductivity, morphology, and electrochemical performance in symmetrical cells.

Main Results:

• The 50:50 PAN/PEO blend demonstrated the highest ionic conductivity of 1 × 10⁻² S/cm at 55 °C.
• Increased succinonitrile (SN) content enhanced the capacity in symmetrical cells, reaching ~140 mAs/cm² for an 18:9:1 polymer:SN:LiBF4 composition.
• The immiscibility of PAN and PEO created distinct interfacial regions, promoting efficient lithium-ion pathways.

Conclusions:

• Electrospun polymer blends, particularly the PAN/PEO system, show significant potential as high-performance SPEs for ASSBs.
• The strategic use of immiscible polymers and plasticizers can effectively enhance ionic conductivity and battery capacity.
• This approach offers a viable strategy for developing advanced materials for next-generation energy storage devices.