Synergistic Microstructure and Thermal Regulation via Multifunctional Flame-Retardant Separator Design for...

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Lithium metal batteries (LMBs) offer high energy density but face safety challenges like thermal runaway due to lithium dendrite growth and flammable electrolytes.
• Current battery separators lack integrated safety features, necessitating advanced solutions for next-generation energy storage.

Purpose of the Study:

• To develop a multifunctional flame-retardant separator for LMBs to mitigate thermal runaway risks.
• To enhance the safety and electrochemical performance of LMBs through synergistic material modification.

Main Methods:

• Composite modification of separators using decabromodiphenyl ethane (DBDPE) as a flame retardant and Al2O3 nanoparticles for mechanical support and ion distribution.
• Characterization of the separator's flame-retardant properties, thermal conductivity, mechanical strength, and ion transport capabilities.
• Electrochemical testing of lithium symmetrical cells and Li/LiFePO4 cells using the modified separators.

Main Results:

• The DBDPE/Al2O3 modified separator demonstrated excellent flame suppression and enhanced thermal conductivity (71.3 mW·m⁻¹·k⁻¹).
• The separator effectively inhibited lithium dendrite growth and promoted uniform lithium-ion distribution.
• Lithium symmetrical batteries operated stably for over 500 hours, and Li/LiFePO4 batteries maintained 138 mAh g⁻¹ over 100 cycles.

Conclusions:

• The multifunctional flame-retardant separator design offers a viable strategy for suppressing thermal runaway in LMBs.
• Synergistic regulation of microstructure and thermal properties in separators is key to achieving both safety and high electrochemical performance.
• This approach provides a groundbreaking roadmap for developing safer, high-energy-density battery systems.