Effect of Low Environmental Pressure on Sintering Behavior of NASICON-Type Li1.3Al0.3Ti1.7(PO4)3 Solid Electrolytes: An In Situ ESEM Study

Solid-state sintering at high temperatures is commonly used to densify solid electrolytes. Yet, optimizing phase purity, structure, and grain sizes of solid electrolytes is challenging due to the lack of understanding of relevant processes during sintering. Here, we use an in situ environmental scanning electron microscopy (ESEM) to monitor the sintering behavior of NASICON-type Li1.3Al0.3Ti1.7(PO4)3 (LATP) at low environmental pressures. Our results show that while no major morphological changes are observed at 10-2 Pa and only coarsening is induced at 10 Pa, environmental pressures of 300 and 750 Pa lead to the formation of typically sintered LATP electrolytes. Furthermore, the use of pressure as an additional parameter in sintering allows the grain size and shape of electrolyte particles to be controlled.

Automated summary

An in situ environmental scanning electron microscopy (ESEM) was used to monitor the sintering behavior of NASICON-type Li1.3Al0.3Ti1.7(PO4)3 (LATP) at low environmental pressures. The results showed that no major morphological changes were observed at 10-2 Pa and only coarsening occurred at 10 Pa, while environmental pressures of 300 and 750 Pa led to the formation of typically sintered LATP electrolytes. Additionally, the use of pressure as an additional parameter in sintering allowed for control of the grain size and shape of the electrolyte particles.