Gel Polymer Electrolytes for Lithium-Ion Batteries Enabled by Photo Crosslinked Polymer Network

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Chemistry

Background:

• Conventional liquid electrolytes (LE) in lithium-ion batteries pose safety risks due to flammability.
• Developing stable and efficient solid-state or gel electrolytes is crucial for next-generation battery technologies.

Purpose of the Study:

• To synthesize and characterize a novel gel polymer electrolyte (GPE) for lithium-ion batteries.
• To optimize the GPE by tuning the ratio of poly(ethylene glycol) diacrylate (PEGDA) and dipentaerythritol hexaacrylate (DPHA) crosslinker.
• To evaluate the electrochemical performance and thermal stability of the developed GPE.

Main Methods:

• Utilized radical photoinitiator and ultraviolet (UV) photopolymerization to form a crosslinked polymer matrix from PEGDA and DPHA monomers.
• Investigated varying ratios of PEGDA and DPHA to create an optimal GPE network.
• Measured ionic conductivity, lithium transference number, and electrochemical cycling performance.

Main Results:

• Achieved a GPE with high ionic conductivity (1.40 mS/cm) and a high lithium transference number (0.65).
• Demonstrated enhanced thermal stability compared to conventional liquid electrolytes.
• Exhibited superior cycle performance with 85.2% capacity retention after 200 cycles, outperforming liquid electrolytes (79.3%).

Conclusions:

• The developed PEGDA/DPHA-based GPE offers a promising alternative to liquid electrolytes for safer and higher-performance lithium-ion batteries.
• The crosslinked polymer network effectively immobilizes liquid electrolyte, enhancing safety and stability.
• Strategic monomer ratio optimization is key to achieving excellent ionic conductivity and cycle life in GPEs.