Regulate transportation of ions and polysulfides in all-solid-state Li-S batteries using ordered-MOF composite solid...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• All-solid-state lithium-sulfur batteries (ASSLSBs) face challenges in balancing high ion conductivity and minimizing lithium polysulfide shuttling.
• Poly(ethylene oxide)-based electrolytes are promising but require structural modification for optimal performance.

Purpose of the Study:

• To introduce an ordered metal-organic framework (MOF) strategy for composite solid electrolytes (CSEs) in ASSLSBs.
• To simultaneously regulate lithium-ion transport and polysulfide shuttling.
• To enhance the overall performance and stability of ASSLSBs.

Main Methods:

• Incorporation of ordered MIL-125-NH2 as fillers into poly(ethylene oxide)-based electrolytes to form a three-dimensional (3D) MPPL composite solid electrolyte (CSE).
• Comparative analysis of electrolytes with ordered MOFs, disordered MOFs, and no MOFs.
• Electrochemical testing of ASSLSBs using the developed CSE.

Main Results:

• The 3D MPPL CSE with ordered MOFs achieved the highest ionic conductivity (8.3 × 10⁻⁴ S/cm at 60°C) compared to control electrolytes.
• ASSLSBs utilizing the 3D MPPL CSE demonstrated stable cycling for 400 cycles at 0.5 C and 60°C.
• The ordered MOF structure effectively regulated both ion and polysulfide transport.

Conclusions:

• The strategy of using ordered MIL-125-NH2 as fillers in PEO-based electrolytes is effective for high-performance ASSLSBs.
• Simultaneous regulation of ion and polysulfide transport is achievable, paving the way for advanced ASSLSBs.
• This approach offers a new pathway towards ASSLSBs with superior energy density and cycling stability.