Revealing Nanoscale Solid-Solid Interfacial Phenomena for Long-Life and High-Energy All-Solid-State Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• All-solid-state batteries (ASSBs) face challenges with high-voltage oxide cathode cyclability due to poor interfacial stability with sulfide solid electrolytes.
• LiNbO3 (LNO) coatings are proposed to mitigate these issues, but their exact mechanisms remain unclear.

Purpose of the Study:

• To elucidate the interfacial mechanisms between LiNbO3-coated high-voltage LiNi0.85Co0.1Al0.05O2 (NCA) cathodes and Li6PS5Cl (LPSCl) solid electrolyte.
• To differentiate between spontaneous interfacial reactions and electrolyte decomposition effects.

Main Methods:

• Advanced characterization techniques (e.g., spectroscopy, microscopy).
• First-principles calculations.
• Electrochemical testing of ASSBs.

Main Results:

• LiNbO3 coating enhances the thermodynamic stability between NCA and LPSCl.
• Electrochemical decomposition of LPSCl at the interface has an in situ passivation effect.
• Combined effects stabilize the interface during the first charge cycle.

Conclusions:

• LiNbO3 coatings are effective in stabilizing the interface of high-voltage oxide cathodes in ASSBs.
• Understanding these interfacial phenomena is key to enabling long cyclability in ASSBs.