PTHF/LATP Composite Polymer Electrolyte for Solid State Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Solid-state lithium-ion batteries (LIBs) require advanced electrolytes to overcome safety and stability issues.
• Polyether-based electrolytes often suffer from poor mechanical properties and rapid degradation.
• Composite polymer electrolytes (CPEs) offer a promising alternative by combining polymer flexibility with ceramic filler properties.

Purpose of the Study:

• To develop and investigate a novel crosslinked composite polymer electrolyte (CPE) for solid-state LIBs.
• To evaluate the synergistic effects of polytetrahydrofuran (PTHF) crosslinking and lithium aluminum titanium phosphate (LATP) ceramic addition.
• To optimize CPE composition and LATP content for enhanced electrochemical performance and mechanical stability.

Main Methods:

• Synthesis of CPEs using PTHF, polyethyleneglycol diacrylate (PEGDA), LATP particles, and LiTFSI salt.
• Systematic variation of film composition and LATP content.
• Characterization of mechanical strength, electrochemical stability, ionic conductivity, and microstructure.
• Temperature-dependent ionic conductivity measurements.

Main Results:

• CPEs with 15 wt% LATP (PPL15) exhibited improved mechanical strength and electrochemical stability.
• A high ionic conductivity of 1.16 × 10^-5 S·cm^-1 was achieved at 80 °C, surpassing PEO-based electrolytes.
• PEGDA incorporation enhanced salt dissociation and ion transport, leading to a uniform microstructure.
• Optimal performance was observed at lower LATP concentrations, indicating the detrimental effect of particle agglomeration.

Conclusions:

• The developed crosslinked CPE system effectively addresses safety concerns and degradation issues in polyether electrolytes.
• The synergistic combination of PTHF crosslinking and LATP incorporation leads to superior performance for solid-state LIBs.
• Further research into optimizing ceramic filler dispersion is crucial for maximizing ion transport and advancing solid-state battery technology.