Liquid-like Poly(ionic liquid) as Electrolyte for Thermally Stable Lithium-Ion Battery

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Developing advanced electrolytes is crucial for enhancing lithium-ion battery performance and safety.
• Poly(ionic liquid)s offer potential as stable electrolyte components due to their unique properties.

Purpose of the Study:

• To synthesize a novel liquid-like poly(ionic liquid) with a low glass transition temperature.
• To evaluate the performance of a poly(ionic liquid)-based electrolyte in lithium-ion batteries.

Main Methods:

• Synthesis of a liquid-like poly(ionic liquid) with a glass transition temperature of -51 °C.
• Formulation of a PIL-based electrolyte with propylene carbonate and LiClO4.
• Electrochemical characterization including ionic conductivity and potential window measurements.
• Battery performance testing using Li/LiFePO4 cells at various temperatures.

Main Results:

• The synthesized poly(ionic liquid) exhibited a low glass transition temperature (-51 °C) and high thermal stability (202.7 °C).
• The PIL-based electrolyte showed high ionic conductivity (8.3 × 10⁻⁵ S cm⁻¹ at 25 °C, 2.0 × 10⁻⁴ S cm⁻¹ at 60 °C) and a wide electrochemical potential window (up to 5.61 V).
• Li/LiFePO4 batteries demonstrated high capacity, excellent cycling stability, and rate capability at 25 °C, with improved performance at 60 °C.

Conclusions:

• The developed poly(ionic liquid)-based electrolyte is highly suitable for advanced lithium-ion battery applications.
• The electrolyte's performance is attributed to the formation of a stable solid-electrolyte interface and its inherent stability.
• This research highlights the potential of poly(ionic liquid)s for next-generation energy storage solutions.