Developing Quasi-Solid-State Ether-Based Electrolytes with Trifluorotoluylation Ionic Liquids for High Voltage...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Quasi-solid-state ether-based electrolytes face challenges like lithium dendrite growth and limited oxidation stability, hindering practical battery applications.
• These issues compromise battery cycle life and energy density, necessitating advanced electrolyte solutions.

Purpose of the Study:

• To design and develop a novel pyrrolidinium-based ionic liquid with a trifluorotoluylation cationic segment for enhanced quasi-solid-state electrolytes.
• To improve electrode/electrolyte interface stability and suppress lithium dendrite formation in high-energy-density batteries.

Main Methods:

• Synthesized a pyrrolidinium-based ionic liquid featuring a trifluorotoluylation cationic segment.
• Investigated the formation of a LiF-rich interphase at the cathode and anode interfaces.
• Fabricated and tested Li-metal full cells (LiFePO4, LiCoO2, LiNi0.8Co0.1Mn0.1O2) using the developed electrolyte.

Main Results:

• The designed ionic liquid induced a robust LiF-rich interphase, enhancing cathode oxidation stability and suppressing transition metal ion dissolution.
• LiF interphases at the anode interface increased modulus and effectively suppressed lithium dendrite growth.
• Full cells demonstrated superior performance at 10 C, 4.5 V, high mass loading, and a wide temperature range (-20-80 °C).
• A 2.66 Ah pouch cell achieved over 356 Wh kg−1 energy density with excellent cyclic stability.

Conclusions:

• The novel pyrrolidinium-based ionic liquid strategy effectively addresses key limitations in quasi-solid-state ether electrolytes.
• This approach paves the way for practical, high-energy-density batteries with enhanced safety and longevity.
• The developed electrolyte shows significant potential for next-generation energy storage solutions.