Ceramic-in-Polymer Composite Solid Electrolyte Enabled by Metal-Sulfur Interactions with Enhanced Li-Ion Conductivity

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Ceramic-in-polymer composite solid electrolytes (SEs) are promising for all-solid-state batteries (ASSBs).
• Their performance is limited by lower Li-ion conductivity compared to pure ceramics due to resistive interphases.
• Improving interfacial properties is crucial for high-performance ASSBs.

Purpose of the Study:

• To develop a novel method for simultaneously modifying ceramic and polymer components in composite solid electrolytes.
• To enhance Li-ion transport across interphases in ceramic-in-polymer composites.
• To improve the overall ionic conductivity and mechanical properties of solid electrolytes for ASSBs.

Main Methods:

• Introduced sulfur-containing functional groups via metal/sulfur interactions.
• Simultaneously modified polyethylene glycol diacrylate (PEGDA) polymer and Li6.4La3Zr1.4Ta0.6O12 (LLZO) ceramic.
• Utilized a layer-by-layer method for manufacturing sulfur-modified LLZO-in-PEGDA composites.
• Investigated metal/sulfur interaction mechanisms and in situ photopolymerization.

Main Results:

• Achieved a high ionic conductivity of 5.1 × 10^-4 S cm^-1 in LLZO-in-PEGDA composites, surpassing pure LLZO.
• Demonstrated enhanced Li-ion transport at both LLZO/LLZO and LLZO/PEGDA interphases.
• Improved toughness and stretchability of the composite solid electrolytes.
• Elucidated the preferential coordination and electron transfer in metal/sulfur interactions.

Conclusions:

• Metal/sulfur interaction-enabled dual modification is a promising strategy for designing advanced ceramic/polymer composite materials.
• This approach effectively enhances ionic conductivity and mechanical properties for ASSB applications.
• The developed method offers broad applicability for rational design of composite solid electrolytes.