Nitrile-functionalized Poly(siloxane) as Electrolytes for High-Energy-Density Solid-State Li Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Liquid electrolytes in lithium-ion batteries pose safety risks.
• Polysiloxane polymers offer potential as solid-state electrolyte alternatives due to their properties.
• Functionalization of polysiloxane backbones is key to enhancing performance.

Purpose of the Study:

• To synthesize and characterize novel polysiloxane-based polymers for lithium-ion conduction.
• To evaluate the ionic conductivity and electrochemical stability of these new polymer electrolytes.
• To assess their performance in lithium-ion battery configurations.

Main Methods:

• Synthesis of polysiloxane polymers via reaction with 2-cyanoethanethiol.
• Functionalization with nitrile groups (60% per chain unit).
• Addition of lithium bis(trifluoromethanesulfonyl)imide salt.
• Ionic conductivity measurements at elevated temperatures.
• Electrochemical performance evaluation in symmetrical and full cells.

Main Results:

• Achieved high ionic conductivity of up to 0.375 mS/cm at 60°C.
• Obtained a high Li+ ion transfer number of 0.73.
• Demonstrated suitability as electrolytes in lithium-ion battery configurations.

Conclusions:

• The synthesized nitrile-functionalized polysiloxane polymers are promising solid electrolytes for lithium-ion batteries.
• These polymers offer a safer alternative to liquid electrolytes with excellent ionic conductivity.
• Further research can explore their long-term stability and performance in practical battery systems.