Synthesis of Li10GeP2S12-type lithium superionic conductors under Ar gas flow.

Numerous studies have reported that sulfide-based materials have potential for applications in all-solid-state lithium batteries. However, the limitations of the synthesis methods of these materials have impeded their progress. In this study, a series of lithium superionic conductors in Li 10+δ Ge 1+δ P 2-δ S 12 (Li 4- x Ge 1- x P x S 4) are synthesized using the Ar gas flow process. This novel process is performed in three steps through heating in the Al 2 O 3 Tamman tube under Ar gas flow; this process is shorter than the conventional five-step vacuum process. The obtained powders show the formation of a Li 10 GeP 2 S 12 -type solid solution with a space group of P 4 2 / nmc in the sequence 0.05 ≤ δ ≤ 0.50 (0.5 ≤ x ≤ 0.65). All the pressed samples show high ionic conductivities over 2.5 mS cm−1. Additionally, 5 g of product per batch was achieved, which is five times more than that obtained using the conventional synthesis process. Establishing a simple synthesis process with a larger product yield could promote the development and evaluation of all-solid-state lithium batteries with large-scale cells using lithium superionic conductors. Image 1 • A Li 10 GeP 2 S 12 -type superionic conductor was prepared via a novel three-step method. • Five grams of Li 10 GeP 2 S 12 per batch were achieved using this novel method. • High conductive properties and reversible battery operation were demonstrated. [ABSTRACT FROM AUTHOR]