Mixing Functionality in Polymer Electrolytes: A New Horizon for Achieving High-Performance All-Solid-State Lithium...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Solid polymer electrolytes (SPEs) are crucial for all-solid-state lithium metal batteries (ASSLMBs).
• A key challenge is simultaneously improving Li+ ion migration and mechanical strength in SPEs.
• Existing SPEs often face limitations in conductivity and structural integrity.

Purpose of the Study:

• To introduce a novel supramolecularly organized, cross-linked polymer electrolyte (PCPE).
• To enhance ionic conductivity and mechanical properties of SPEs for ASSLMBs.
• To investigate the role of a multi-arm boron-containing oligomer (MBO) in modifying SPE characteristics.

Main Methods:

• Synthesized a PCPE by incorporating an MBO solid plasticizer into a polyethylene oxide (PEO)-lithium salt matrix.
• Investigated the Lewis acid-base interactions between boron sites in MBO and lithium salt anions.
• Analyzed the resulting supramolecular polymer network structure and its impact on ion transport and mechanical properties.

Main Results:

• The MBO-salt interaction created an amorphous subphase with nanochannels facilitating rapid Li+ transport.
• The supramolecular network formed by MBO and PEO improved mechanical strength and provided interconnected ion pathways.
• The PCPE exhibited enhanced ionic conductivity, superior mechanical properties, and improved film stability.
• Demonstrated dendrite-free cycling in Li/Li symmetric cells for over 2600 hours.
• Achieved excellent electrochemical performance in high-capacity ASSLMBs.

Conclusions:

• The developed PCPE effectively addresses the trade-off between ionic conductivity and mechanical strength in SPEs.
• Supramolecular organization via MBO is a promising strategy for designing advanced electrolytes for ASSLMBs.
• The PCPE shows significant potential for enabling safe and high-performance solid-state batteries.