Facile Strategy to Prepare Poly(ionic liquid)-Coated Solid Polymer Electrolytes through Layer-by-Layer Assembly

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Solid polymer electrolytes are crucial for lithium metal batteries (LMBs) but face challenges balancing mechanical strength and ionic conductivity.
• Layer-by-layer (LbL) assembly has shown promise for creating flexible solid polymer electrolytes for electrochemical devices.

Purpose of the Study:

• To develop a novel strategy for constructing solid polymer electrolytes with enhanced ionic conductivity and mechanical properties.
• To investigate the performance of these electrolytes in lithium metal battery applications.

Main Methods:

• Utilized LbL assembly to create ultrathin electrolyte membranes with alternating polyanion and polycation layers.
• Incorporated poly(ionic liquid) backbones and polyethylene glycol (PEG) side groups to enhance lithium-ion transport.
• Fabricated free-standing membranes and assembled them into Li/LiFePO4 battery cells.

Main Results:

• Achieved good ionic conductivities ranging from 9.03-10 × 10^-4 S cm^-1.
• Demonstrated high initial discharge capacity (143-158 mAhg^-1) at 60 °C with high coulombic efficiency in Li/LiFePO4 cells.
• Obtained solid polymer electrolyte membranes with superior ionic conductivity and mechanical robustness.

Conclusions:

• The combined approach of polymer synthesis and LbL self-assembly provides an effective route for fabricating advanced solid polymer electrolytes.
• These electrolytes show significant potential for use in flexible electrochemical devices and high-voltage battery applications.