Solid Polymer Electrolyte with Dual Lewis-Acid Filler for Ultra-Stable Lithium Metal Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Solid polymer electrolytes (SPEs) offer safer alternatives to liquid electrolytes in lithium metal batteries.
• Lithium dendrite formation remains a critical challenge hindering SPE performance and safety.
• Systematic studies on dendrite growth mechanisms in SPEs are lacking.

Purpose of the Study:

• To elucidate the determinants of lithium dendrite growth in SPEs using Sand's equation.
• To propose an effective strategy for constructing dendrite-free polymer lithium metal batteries.
• To evaluate the performance of novel SPEs with dual-Lewis-acid materials.

Main Methods:

• Application of Sand's equation to analyze Li+ ion transport and plating/striping behaviors.
• Incorporation of dual-Lewis-acid materials (Zinc Borate) into PVDF-HFP based SPEs.
• Electrochemical testing of Li metal batteries utilizing the developed SPEs.

Main Results:

• Sand's equation reveals Li+ transference number, diffusion coefficient, and concentration positively correlate with dendrite growth time.
• The PVDF-HFP/Zinc Borate SPE achieved a high Li+ transference number (0.9) and ionic conductivity (9.2 × 10-4 S cm-1 at 30°C).
• Demonstrated exceptional cycling stability in LFP//Li and LiNi0.6Mn0.2Co0.2O2//Li cells over hundreds to thousands of cycles.

Conclusions:

• Dual-Lewis-acid materials effectively suppress lithium dendrite formation in SPEs.
• The developed SPEs exhibit superior ionic conductivity and Li+ transport properties compared to single-Lewis-acid systems.
• This work presents a promising pathway for developing safe and high-performance polymer lithium metal batteries.