Artificial Crystalline-Amorphous Architecture Enables Continuous Ion Transport in Poly(Vinylidene Fluoride)-Based...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Solid-state polymer electrolytes (SPEs) are crucial for next-generation batteries but suffer from low ionic conductivity due to crystalline regions hindering ion transport.
• Fully amorphous polymers lack mechanical stability, posing challenges for practical battery applications.
• Existing SPEs often exhibit limited ionic conductivity, restricting their performance in high-energy-density batteries.

Purpose of the Study:

• To design and fabricate an "artificial crystalline-amorphous" architecture to overcome the limitations of traditional SPEs.
• To create continuous ion transport pathways within SPEs while maintaining mechanical robustness.
• To significantly enhance ionic conductivity and electrochemical performance for advanced battery applications.

Main Methods:

• Fabrication of an oriented electrospun fibrous framework using polar semi-crystalline poly(vinylidene fluoride-co-chlorotrifluoroethylene) (PVT).
• Infiltration of the framework with amorphous PVT to create a continuous ion conduction network.
• Characterization of the resulting SPEs' ionic conductivity, mechanical properties, and electrochemical stability.

Main Results:

• Achieved an exceptionally high ionic conductivity of 1.23 mS cm^-1 at 25°C, surpassing most reported all-polymeric SPEs.
• Demonstrated stable Li//Li symmetric cell cycling for over 1300 hours at 0.2 mA cm^-2, significantly outperforming control cells.
• Confirmed stable cycling performance in high-voltage Ni_0.8Co_0.1Mn_0.1O₂ (NCM811)//Li full cells at 25°C.

Conclusions:

• The artificial crystalline-amorphous architecture effectively transforms isolated amorphous conduction zones into continuous pathways.
• This novel structure provides robust mechanical support and facilitates efficient ion transport, leading to superior battery performance.
• The study presents a new strategy for enhancing ion transport in SPEs through microstructural engineering.