Densification of a NASICON-Type LATP Electrolyte Sheet by a Cold-Sintering Process

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• All-solid-state batteries (ASSBs) offer enhanced safety and energy density compared to conventional lithium-ion batteries.
• Developing solid electrolytes with high ionic conductivity and good interfacial properties remains a critical challenge.
• NASICON-type materials, such as Li1.3Al0.3Ti1.7(PO4)3 (LATP), are promising candidates for solid electrolytes.

Purpose of the Study:

• To fabricate a NASICON-type LATP electrolyte sheet using a cold sintering process (CSP).
• To control the microstructure of the LATP sheet to enhance wettability for effective CSP.
• To investigate the effect of CSP on the densification and ionic conductivity of the LATP electrolyte.

Main Methods:

• Fabrication of Li1.3Al0.3Ti1.7(PO4)3 (LATP) electrolyte sheets via cold sintering process (CSP).
• Preparation of porous LATP sheets through calcination to remove organic components and create porosity.
• Microstructural analysis and ionic conductivity measurements of the sintered LATP sheets.

Main Results:

• Controlled microstructure of LATP sheets improved wettability, a key factor for CSP.
• Calcination created a porous structure essential for subsequent densification during CSP.
• CSP led to grain boundary densification, with increased densification observed over longer reaction times.
• Total ionic conductivity of the LATP sheet increased significantly from 3.0 × 10^-6 S/cm to 3.0 × 10^-4 S/cm due to particle neck formation.

Conclusions:

• Cold sintering process is effective for fabricating dense LATP solid electrolyte sheets.
• Microstructure control and CSP parameters are crucial for optimizing ionic conductivity.
• The improved conductivity demonstrates the potential of CSP-processed LATP for advanced all-solid-state batteries.