Novel sulfur-doped single-ion conducting multi-block copolymer electrolyte

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Solid-state lithium batteries offer promising electrochemical energy storage but face challenges with current solid electrolytes.
• Inorganic and polymer electrolytes require improvements to replace liquid organic electrolytes in batteries.
• Combining different electrolyte systems is an emerging strategy to address these limitations.

Purpose of the Study:

• To synthesize and characterize a novel sulfur-doped single-ion conducting multi-block copolymer (SIC-BCE).
• To evaluate the SIC-BCE as an interlayer for solid-state lithium batteries, particularly with sulfide electrolytes.
• To assess the polymer's ionic conductivity, interfacial properties, and electrochemical stability.

Main Methods:

• Synthesis of a sulfur-doped single-ion conducting multi-block copolymer (SIC-BCE).
• Characterization of the SIC-BCE's properties, including ionic conductivity when swollen with ethylene carbonate.
• Electrochemical testing in symmetric cells (Cu|SIC-BCE|Li6PS5Cl|SIC-BCE|Cu) to evaluate lithium stripping/plating and interfacial stability.

Main Results:

• The novel SIC-BCE exhibits excellent ionic conductivity when swollen with ethylene carbonate.
• Stable lithium stripping and plating were observed with the SIC-BCE system.
• The polymer demonstrated suitable electrochemical stability against reduction and oxidation.
• Tests confirmed the polymer's ability to stabilize the electrode-electrolyte interface, preventing direct contact between the sulfide electrolyte and metallic copper.

Conclusions:

• The developed SIC-BCE shows significant potential as an interlayer in solid-state lithium batteries.
• This polymer enhances interfacial contact and electrochemical stability when used with sulfide electrolytes like Li6PS5Cl.
• The SIC-BCE contributes to overcoming challenges associated with solid-state battery electrolytes.