Multilayer Separator-Driven interface stabilization and dendrite suppression for Long-Cycling lithium metal batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium metal batteries (LMBs) offer high energy density but suffer from lithium dendrite growth and side reactions, limiting their practical use.
• Dendrite formation leads to short circuits, capacity fading, and safety hazards like thermal runaway.

Purpose of the Study:

• To design and evaluate a novel multilayer separator for lithium metal batteries.
• To suppress lithium dendrite growth and improve the cycling stability and safety of LMBs.

Main Methods:

• Fabrication of a trilayer separator using methanol-intercalated Li-Al hydrotalcite-like nanosheets sandwiched between PVDF-HFP nanofiber membranes.
• Characterization of the separator's thermal stability, mechanical strength, electrolyte wettability, and ionic conductivity.
• Electrochemical testing of Li symmetric cells and Li||LiFePO4 cells using the developed separator.

Main Results:

• The trilayer separator exhibited enhanced thermal stability, mechanical strength, and electrolyte wettability.
• The separator facilitated uniform Li+ deposition and suppressed dendrite growth, achieving a high Li+ transference number (0.89) and ionic conductivity (1.20 mS cm-1).
• Li symmetric cells demonstrated stable cycling for over 2800 h with low voltage polarization, and Li||LiFePO4 cells maintained 91.6% capacity after 1000 cycles at 2C.

Conclusions:

• The designed multilayer separator effectively addresses key challenges in lithium metal battery technology.
• The hierarchical porous structure and Lewis acid sites of the hydrotalcite nanosheets promote ion transport and dendrite suppression.
• This work offers a promising strategy for developing high-performance and safe lithium metal batteries.