Interface Design Enabling Stable Polymer/Thiophosphate Electrolyte Separators for Dendrite-Free Lithium Metal...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Interfacial stability is crucial for solid-state battery (SSB) performance.
• Understanding organic/inorganic interfaces in composite solid electrolytes (SEs) is key for Li+ transport.
• Current knowledge gaps in interfacial instability hinder composite SE application in SSBs.

Purpose of the Study:

• To investigate the chemical degradation between Li6PS5Cl (LPSCl) and poly(ethylene glycol) (PEG).
• To explore interface engineering strategies for stabilizing composite SEs and improving SSB performance.
• To demonstrate a method for achieving dendrite-free lithium metal batteries.

Main Methods:

• Chemical analysis of LPSCl/PEG interfaces.
• Electrochemical characterization of composite SEs.
• Interface modification using substituted PEG and LiF-rich layers.

Main Results:

• High polarity of PEG induces chemical degradation of LPSCl by altering PS43- tetrahedra.
• A substituted PEG terminal group stabilizes interfaces and broadens the electrochemical window.
• A LiF-rich layer effectively suppresses side reactions at the Li/SE interface.

Conclusions:

• Insights into the chemical stability of polymer/sulfide composite SEs are provided.
• Interface design strategies are demonstrated for enhanced SSB performance.
• Achieved dendrite-free lithium metal batteries through optimized interfacial engineering.