Long-Life and High-Rate-Charging Lithium Metal Batteries Enabled by a Flexible Active Solid Electrolyte Interphase...

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Lithium metal batteries face challenges with lithium dendrite growth and electrolyte consumption.
• Existing artificial solid electrolyte interphases (SEIs) often lack multifunctionality and optimal conductivity.
• Developing a stable, multifunctional SEI is crucial for advancing lithium metal battery technology.

Purpose of the Study:

• To introduce a simple method for creating a stable, multifunctional solid electrolyte interphase (SEI) for lithium metal batteries.
• To improve the conductivity and nucleation potential of the SEI layer.
• To enhance the performance and cycle life of lithium metal batteries through electrolyte modification.

Main Methods:

• A universal and simple method involving the addition of a multifunctional fluorosulfonate to a commercial electrolyte.
• Formation of an SEI with increased inorganic LiF content.
• Creation of a flexible interface layer by combining the imidazole ring of fluorosulfonate with the electrolyte's alkyl group.

Main Results:

• The modified electrolyte successfully inhibited lithium dendrite growth and promoted uniform lithium deposition.
• Symmetrical batteries demonstrated stable deposition for nearly 300 hours at 20 mA/cm² with 2 mAh/cm² capacity.
• Li-LiFePO₄ (LFP) full cells maintained 90.6% capacity after 1000 cycles at 5 C.
• Fast charging (5 C) performance showed 76.56% capacity retention after 200 cycles, four times better than commercial electrolytes.

Conclusions:

• The addition of multifunctional fluorosulfonate is a simple yet effective strategy for constructing stable SEIs in lithium metal batteries.
• This approach significantly enhances battery performance, particularly under fast charging conditions.
• The findings offer valuable insights for the practical application and commercialization of advanced lithium metal batteries.