Regulating Lithium Plating/Stripping Behavior by a Composite Polymer Electrolyte Endowed with Designated Ion Channels

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium metal batteries (LMBs) are crucial for high energy density storage.
• Challenges include unstable solid electrolyte interphase (SEI) and lithium dendrite growth.
• Advanced electrolytes are needed for safe and efficient LMBs.

Purpose of the Study:

• To develop a composite polymer electrolyte (CPE) for stable lithium plating/stripping.
• To address SEI instability and dendrite issues in LMBs.
• To improve the overall performance and safety of lithium metal batteries.

Main Methods:

• Fabrication of a CPE using nanoscale Uio66-NH2 with a uniform pore structure.
• Utilizing Uio66-NH2 channels as an ion sieve for selective Li+ transport.
• Characterization of ion conductivity, oxidation stability, and SEI formation.

Main Results:

• Achieved a high Li-ion transference number (0.6) due to selective Li+ extraction.
• Demonstrated high ionic conductivity (0.245 mS cm-1) and an expanded oxidation window (5.1 V).
• Symmetric cells cycled over 500 hours without short-circuiting; Li/CPE/LFP cells showed 99% capacity retention after 100 cycles.

Conclusions:

• The designed CPE effectively regulates Li plating/stripping via Uio66-NH2 channels.
• The electrolyte enhances ionic conductivity, electrochemical stability, and SEI properties.
• This approach offers a promising strategy for developing high-performance and safe lithium metal batteries.