Plasma Design of Alloy-Based Gradient Solid Electrolyte Interphase on Lithium Metal Anodes for Energy Storage

Area of Science:

• Materials Science
• Electrochemistry
• Plasma Physics

Background:

• Solid electrolyte interphase (SEI) design is crucial for high-performance lithium metal anodes.
• Current SEI strategies face challenges in controlling lithium deposition and ensuring long-term stability.

Purpose of the Study:

• To develop a novel method for constructing a gradient SEI on lithium metal anodes.
• To investigate the synergistic effects of the gradient SEI on lithium deposition kinetics, structure, and crystal orientation.

Main Methods:

• Utilized a SnCl4/trifluorotoluene hybrid plasma technology to create a Li-Sn alloy-based gradient SEI.
• Characterized the SEI's layered structure, composition, and mechanical properties (Young's modulus).
• Evaluated the electrochemical performance of the modified lithium metal anode in a pouch cell.

Main Results:

• Successfully engineered a gradient SEI with distinct layers: Li-Sn alloy, LiF, and LiCl/organic lithium compounds.
• The gradient SEI exhibited a high Young's modulus (13.9 GPa) and enhanced structural stability.
• Achieved uniform lithium deposition without dendrite growth, leading to low overpotential and high coulombic efficiency.

Conclusions:

• The hybrid plasma technology offers a pioneering strategy for fabricating advanced lithium metal anodes.
• The gradient SEI effectively regulates lithium deposition, improving anode performance and battery cycling stability.
• This approach holds significant promise for the development of next-generation energy storage devices.