In-Cavity Lithium Deposition Enabled by Carbon Framework-Integrated Separator for Stable Low-Pressure Cycling.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium metal anodes are crucial for high-energy-density batteries but suffer from dendritic growth, leading to safety issues and cell failure.
• External pressure can improve lithium plating density but has practical limitations.

Purpose of the Study:

• To develop a functional separator that regulates lithium plating and stripping behavior under reduced external pressure.
• To enable stable and efficient operation of lithium metal batteries.

Main Methods:

• Fabrication of a carbon framework-integrated separator using electrophoretic deposition of carbon nanofibers (CNFs) onto a porous separator.
• Experimental characterization and computational studies of the separator's performance with a lithium metal anode.
• Assembly and testing of a high-voltage, high-capacity full cell.

Main Results:

• The carbon framework-integrated separator promotes kinetics-controlled 'in-cavity' deposition of lithium.
• Dense lithium plating and accommodation of volume changes during plating/stripping were achieved.
• A full cell demonstrated stable cycling at 4.25 V and 4.0 mAh cm⁻² under low external pressure (0.26 MPa).

Conclusions:

• The proposed carbon framework-integrated separator is a promising strategy for designing advanced separators.
• This approach facilitates practical implementation of high-energy-density lithium metal batteries by addressing lithium plating issues.
• The technology enables stable battery performance under reduced external pressure, enhancing safety and practicality.