A Novel Time-Saving Synthesis Approach for Li-Argyrodite Superionic Conductor

The wet-chemical synthetic approach for Li-argyrodite superionic conductors for all-solid-state batteries (ASSBs) is promising as it saves time, energy, and cost, while achieving scalable production. However, it faces certain commercialization issues such as byproduct generation, nucleophilic attack of the solvent, and long processing times. In this study, a facile and time-saving microwave-assisted wet synthesis (MW-process) approach is proposed for Li₆PS₅Cl (LPSC), which is completed in 3 h at the precursor-synthesis stage. The LPSC crystal obtained from the MW-process presents various advantages such as fast-PS₄³⁻ generation, high solubility of LiCl, and low adverse effects from solvent molecules. These features help in achieving a high Li-ion conductivity (2.79 mS cm⁻¹) and low electric conductivity (1.85×10⁻⁶ mS cm⁻¹). Furthermore, the LPSC crystal is stable when reacting with Li metal (2000 h at 0.1 mA cm⁻²) and exhibits superior cyclability with LiNi_0.6Co_0.2Mn_0.2 (NCM622) (145.5 mA h g⁻¹ at 0.5 C, 200 cycles with 0.12% of capacity loss per cycle). The proposed synthetic approach presents new insights into wet-chemical engineering for sulfide-based solid-electrolytes (SEs), which is crucial for developing ASSBs from a commercial-scale perspective.