Magnetic Field-Driven Ion Selectivity Boosts LiF-Rich SEI Formation for Enhanced Lithium Metal Battery Performance...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium metal anodes offer high theoretical capacity but face commercialization hurdles due to volume expansion, side reactions, and dendrite formation.
• Existing solutions struggle to overcome the inherent instability of lithium metal anodes in batteries.

Purpose of the Study:

• To develop a novel separator modification strategy to enhance the electrochemical performance and stability of lithium metal batteries.
• To investigate the role of tannic acid, cobalt ions, and an external magnetic field in mitigating lithium anode challenges.

Main Methods:

• Covalent modification of polypropylene separators using tannic acid and Co2+ ions.
• Application of an external magnetic field during battery operation.
• Analysis of ion adsorption (CO32- and F-) on modified separators and the resulting solid electrolyte interface (SEI) formation.

Main Results:

• Modified TA-Co/PP separators selectively adsorb CO32- ions while inhibiting F- ion uptake, promoting a LiF-rich SEI.
• Batteries with TA-Co/PP separators and a magnetic field achieved 90% Coulombic efficiency over 650 cycles at 1 mA cm-2.
• Lithium symmetric cells with TA-Co/PP separators exhibited low polarization (20 mV) at 60 °C and 4 mA cm-2.

Conclusions:

• The proposed separator modification effectively stabilizes lithium metal anodes, enhancing battery cycle life and performance.
• The synergistic effect of TA-Co modification and magnetic field application offers a promising pathway for commercializing high-performance lithium metal batteries across various temperatures.