Dual-Component Interlayer Enables Uniform Lithium Deposition and Dendrite Suppression for Solid-State Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• β-Lithium thiophosphate (LPS) is a promising ceramic electrolyte for high-energy-density all-solid-state batteries due to its high Li+ conductivity.
• Integrating LPS with lithium metal anodes offers the highest theoretical capacity but is limited by short-circuiting due to dendrite formation at practical current densities.

Purpose of the Study:

• To design and implement an in situ formed interfacial protective layer to suppress lithium dendrite growth in LPS-based solid-state batteries.
• To enhance the critical current density and overall performance of solid-state lithium batteries.

Main Methods:

• Fabrication of a dual-component LiSn-LiN protective layer between the lithium electrode and LPS electrolyte.
• Utilizing X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS) analyses to study the interlayer's structure and formation.
• Electrochemical testing to evaluate critical current density and dendrite suppression.

Main Results:

• The LiSn-LiN interlayer effectively suppressed lithium dendrite formation by promoting uniform lithium deposition (Li22Sn5) and preventing penetration (Li3N).
• The protective layer more than doubled the deliverable critical current density compared to unprotected systems.
• The formation kinetics and local structure of the Li22Sn5 phase were elucidated.

Conclusions:

• A dual-component interfacial layer (LiSn-LiN) can be effectively designed and formed in situ to mitigate dendrite issues in LPS-based solid-state batteries.
• Tailoring protective layer structure based on specific battery configurations and interfacial chemistry is crucial for optimizing performance.
• This approach offers a viable strategy for developing safer and more practical high-energy-density all-solid-state batteries.