Ultrahigh Areal Capacity Li Electrodeposition at Metal-Solid Electrolyte Interfaces under Minimal Stack Pressures...

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Batteries

Background:

• High energy density rechargeable batteries require metallic electrodes, but Li metal-solid electrolyte interfaces suffer from impedance growth.
• Void formation during cycling at practical current densities and capacities limits the performance of current solid-state batteries.

Purpose of the Study:

• To investigate a method for improving interfacial stability in solid-state metal batteries.
• To enable higher areal capacities and current densities for lithium metal anodes.

Main Methods:

• Introduction of a sodium-potassium (Na-K) liquid wetting film between lithium metal and a solid electrolyte (Li$_{6.75}$La$_{3}$Zr$_{1.75}$Ta$_{0.25}$O$_{12}$ - LLZTO).
• Cycling of lithium metal anodes with the Na-K liquid interface at high current densities and areal capacities.
• Analysis of cell impedance and interfacial behavior during lithium stripping and plating.

Main Results:

• Reversible stripping and plating of 150 μm Li (30 mAh cm^-2) achieved, approximately 10 times the capacity of current lithium-ion batteries.
• Stable cycling at current densities > 0.5 mA cm^-2 and pressures < 75 kPa with minimal impedance changes.
• Performance improvement attributed to the Na-K liquid at the lithium stripping interface.

Conclusions:

• The Na-K liquid interfacial film effectively suppresses impedance growth and enables high-performance cycling of lithium metal anodes.
• This approach overcomes critical interfacial stability issues hindering solid-state metal battery development.
• The strategy holds significant promise for advancing next-generation rechargeable battery technologies.