Polyurethane-P₂S₅ composite-based solid-state electrolyte assists low polarization and high stability all-solid-state...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Polyurethane (PU) block copolymers are promising solid electrolytes for lithium-metal batteries due to mechanical strength.
• Hard segments in PU limit ion transport, causing polarization, poor cycle stability, and capacity fade.

Purpose of the Study:

• To develop a novel composite polymer solid electrolyte (SPE) with improved chemical stability and electrolyte-electrode interaction.
• To suppress polarization phenomena and enhance cycle performance in lithium-metal batteries.

Main Methods:

• Modulating soft segments in block copolymer PU.
• Synthesizing a new SPE via ion-conduct segment modification using P2S5.
• Characterizing ion conductivity and electrochemical performance of the SPE in LiFePO4 (LFP)|SPE|Li batteries and lithium symmetric cells.

Main Results:

• Achieved ion conductivity of 7.4 × 10⁻⁴ S cm⁻¹ at 25 °C and 4.3 × 10⁻³ S cm⁻¹ at 80 °C.
• Demonstrated high specific capacity and stable charge/discharge platforms in LFP|SPE|Li cells.
• Obtained 90% capacity retention after 2000 cycles at 5C and over 750 hours of stable cycling in lithium symmetric cells with negligible polarization.

Conclusions:

• Modulating soft segments in PU block copolymers is an effective strategy to suppress polarization.
• The developed P2S5-modified SPE offers long cycle stability and high capacity retention for advanced lithium-metal batteries.