Surface-Confined Disordered Hydrogen Bonds Enable Efficient Lithium Transport in All-Solid-State PEO-Based Lithium...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Polyethylene oxide (PEO)-based electrolytes are crucial for developing safe and high-energy-density all-solid-state lithium batteries (ASSLBs).
• Inefficient lithium-ion (Li+) transport in PEO limits battery rate performance and stability.
• Regulating hydrogen bonds (H-bonds) is key for Li+ transport, but challenges include electrochemical instability and restricted mobility.

Purpose of the Study:

• To overcome limitations in PEO-based electrolytes by developing a novel surface-confined disordered H-bond system.
• To improve Li+ transport and electrochemical stability for enhanced ASSLB performance.

Main Methods:

• Design and synthesis of a surface-confined disordered H-bond system within PEO-based electrolytes.
• Utilizing stable donor-acceptor interactions to create a loosened chain segment/ion arrangement.
• Fabrication and testing of a lithium iron phosphate (LiFePO4)-based ASSLB using the developed electrolyte.

Main Results:

• The new system inhibited PEO crystallization, weakened Li+ coordination, and entrapped anions, facilitating efficient Li+ transport.
• The LiFePO4-based ASSLB achieved over 400 cycles at 1.0 C and 65°C with 87.5% capacity retention.
• Performance surpassed most reported polymer-based ASSLBs, demonstrating improved cycle life and stability.

Conclusions:

• Confined disordered H-bonds are vital for optimizing Li+ transport in polymer-based ASSLBs.
• This approach offers a promising strategy for designing advanced solid-state electrolytes.
• The study paves the way for future high-performance and safe all-solid-state batteries.