Li₇La₃Zr₂O₁₂-co-LiNbO₃ Surface Modification Improves the Interface Stability between Cathode and Sulfide Solid-State...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Thiophosphate-based all-solid-state batteries (ASSBs) are promising for energy storage and electric vehicles.
• Interfacial issues between high-voltage cathodes and solid electrolytes hinder ASSB commercialization.
• Surface coatings offer a viable solution to mitigate direct contact and improve interfacial stability.

Purpose of the Study:

• To fabricate and evaluate dual-layer oxide coatings (LLZO and LNO) on LiCoO2 (LCO) cathodes.
• To investigate the effectiveness of these coatings in improving the performance of thiophosphate-based ASSBs.
• To address the interfacial challenges in high-voltage ASSBs through a simple and scalable coating method.

Main Methods:

• Fabrication of Li7La3Zr2O12 (LLZO) and LiNbO3 (LNO) coatings on LiCoO2 (LCO) via a two-step sol-gel process.
• In-situ interfacial growth of high-Li+ conductive oxide electrolytes.
• Electrochemical evaluation of coated LCO cathodes in thiophosphate-based ASSBs (LLZO&LNO@LCO||LPSC||Li-In).

Main Results:

• Dual-layer LLZO-co-LNO coatings significantly improved long-term cycling performance and discharge capacity compared to uncoated LCO.
• ASSBs with LLZO&LNO@LCO cathodes demonstrated high discharge capacities at various rates (e.g., 138.8 mAh/g at 0.05 C).
• Excellent capacity retention of 98% after 300 cycles at 0.05 C was achieved, highlighting coating effectiveness.

Conclusions:

• The developed LLZO and LNO dual-layer coating strategy effectively solves interfacial problems in thiophosphate-based ASSBs.
• This approach offers a promising, low-cost, and scalable method for enhancing cathode materials in ASSBs.
• The findings pave the way for the commercialization of high-performance all-solid-state batteries.