Insight into the Microstructure and Ionic Conductivity of Cold Sintered NASICON Solid Electrolyte for Solid-State...

Area of Science:

• Materials Science
• Electrochemistry
• Solid-state Chemistry

Background:

• Lithium aluminum titanium phosphate (LATP) is a key solid electrolyte for lithium batteries, known for its high ionic conductivity.
• Conventional LATP densification requires high-temperature sintering (~1000 °C), posing challenges for large-scale manufacturing and energy efficiency.

Purpose of the Study:

• To investigate a novel cold sintering process combined with post-annealing for densifying LATP.
• To evaluate the ionic conductivity, relative density, and microstructural characteristics of cold-sintered LATP.
• To explore the potential of this new process for advancing all-solid-state battery technology.

Main Methods:

• Cold sintering of LATP pellets at 120 °C.
• Post-annealing of cold-sintered pellets at 650 °C.
• Characterization using ionic conductivity measurements and high-resolution transmission electron microscopy (HRTEM).

Main Results:

• Achieved a relative density of 93% and ionic conductivity of 8.04 × 10⁻⁵ S cm⁻¹ at room temperature.
• Determined a low activation energy of 0.37 eV for lithium-ion transport.
• HRTEM revealed interconnected particles with nanocrystalline precipitates at grain boundaries, facilitating ion transport.

Conclusions:

• The developed cold sintering process offers a simpler and potentially more energy-efficient alternative to traditional high-temperature sintering for LATP.
• Nanocrystalline-enriched grain boundaries in cold-sintered LATP enhance lithium-ion conductivity.
• This approach opens new avenues for the cost-effective fabrication of all-solid-state batteries.