Flexible Composite Electrolyte Membranes with Fast Ion Transport Channels for Solid-State Lithium Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Composite polymer electrolyte (CPE) membranes are crucial for all-solid-state batteries (SSBs).
• Existing CPEs face challenges in ionic conductivity and mechanical strength, limiting their practical use.
• Developing advanced electrolytes is key to improving SSB safety and performance.

Purpose of the Study:

• To design and fabricate a flexible composite electrolyte membrane (FCPE) with enhanced ion transport for all-solid-state batteries.
• To investigate the structural and electrochemical properties of the novel FCPE.
• To evaluate the cycling stability and performance of SSBs utilizing the FCPE.

Main Methods:

• Fabrication of FCPE using phase conversion and in situ polymerization.
• Incorporation of polyvinylidene fluoride-hexafluoro propylene (PVDF-HFP) and lithium lanthanum zirconate (LLZTO) to form a 3D net-like structure.
• In situ polymerization of polyvinyl ethylene carbonate (PVEC) to improve interfacial contact.

Main Results:

• The FCPE exhibits a 3D network structure with rapid Li+ transport pathways, promoting uniform lithium deposition.
• Symmetrical lithium cells demonstrated high stability over 1200 hours of cycling at 0.1 mA cm-2.
• All-solid-state lithium batteries with LiFePO4 cathodes showed stable cycling for over 100 cycles at room temperature with high Coulombic efficiency.
• Infrared spectroscopy confirmed the structural stability of the FCPE after 100 cycles.

Conclusions:

• The developed FCPE offers a promising solution for enhancing ionic conductivity and mechanical properties in solid-state electrolytes.
• The unique 3D network structure facilitates efficient ion transport and stable lithium metal anode cycling.
• This work provides a novel strategy for designing high-performance, flexible composite electrolytes for safer and more reliable all-solid-state batteries.