Nanotrench Superfilling Facilitates Embedded Lithium Anode for High-Areal-Capacity Solid-State Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Solid-state batteries (SSBs) offer high energy density and improved safety over conventional lithium-ion batteries.
• Lithium metal anodes are crucial for high-energy SSBs but face challenges due to interface degradation with solid-state electrolytes (SSEs).
• Fast interface degradation between lithium metal and SSEs leads to high interfacial resistance and limits battery performance.

Purpose of the Study:

• To develop a stable and high-performance interface for lithium metal anodes in garnet-based solid-state batteries.
• To mitigate interface degradation and improve lithium ion transport across the Li-SSE interface.
• To enhance the critical current density and cycling stability of lithium metal anodes.

Main Methods:

• Fabrication of a quasi-3D interphase on a garnet SSE using lithiophilic nanotrenches.
• Induction of lithium metal superfilling into the created nanotrenches.
• Characterization of interfacial resistance and lithium deposition/stripping behavior.
• Testing of Li||LiFePO4 solid-state batteries with the modified anode.

Main Results:

• Achieved a low interfacial resistance of 4 Ω cm² due to lithium metal superfilling into nanotrenches.
• Extended lithium deposition/stripping into the bulk anode (∼10 μm), enhancing stability.
• Realized a high critical current density of 1.8-2.0 mA cm⁻² at room temperature.
• Demonstrated a high reversible areal capacity of ∼3.0 mAh cm⁻² in Li||LiFePO4 SSBs at room temperature.

Conclusions:

• The proposed quasi-3D interphase effectively stabilizes the lithium metal anode-SSE interface.
• Lithophilic nanotrenches promote uniform lithium plating and stripping, improving battery performance.
• This approach offers a promising strategy for developing safe and high-energy solid-state batteries.