Methodology for enhancing the ionic conductivity of superionic halogen-rich argyrodites for all-solid-state lithium batteries

The development of high-performance all-solid-state lithium-ion batteries depends on the realization of solidstate electrolytes with high ionic conductivity. In this study, halogen-rich argyrodites with high ionic conductivities were fabricated, and their structural evolution was studied. In addition, the optimum heat treatment protocol for enhancing the ionic conductivity of halogen-rich argyrodites (Li5.3PS4.3Cl1.7) was determined by interpreting the reaction mechanism. Structural and thermal analyses revealed that fast heating results in the formation of intermediates containing PS43- units and Cl- ions, which remain in the material and decrease the ionic conductivity (similar to 1.6 mS/cm at 25 degrees C). Surprisingly, slow heating, such as step heating, can promote the slow reaction that produces argyrodite from an intermediate, resulting in a high ionic conductivity (similar to 5.0 mS/cm at 25 degrees C). Furthermore, we examined the performance of all-solid-state batteries assembled with Li5.3PS4.3Cl1.7 as a solid-state electrolyte and found that the batteries employing Li5.3PS4.3Cl1.7 treated by a slow heating protocol performs better than the batteries employing Li5.3PS4.3Cl1.7 treated by a fast heating protocol, with an impressive specific capacity of 151.8 mAh/g at 1.0 C. Herein, we assert that further developing halogen-rich argyrodites as glass-ceramics may provide a long-sought solution to realizing ASSBs capable of achieving a high rate.

Automated summary

The study discovered halogen-rich argyrodites with high ionic conductivities and determined the optimal heat treatment protocol. Analysis of different heating speeds showed that slow heating promotes high ionic conductivity. Experimental results of all-solid-state batteries indicated that materials treated with slow heating outperformed those treated with fast heating.