Mechanochemical synthesis and characterization of Na3-xP1-xWxS4 solid electrolytes

[摘要] All-solid-state sodium batteries are attracting attention as next-generation batteries, owing to their improved safety and abundance of sodium resources. To realize all-solid-state sodium batteries, solid electrolytes with high sodium-ion conductivities are required. In this study, Na3PS4 electrolytes with partial substitution of P5+ with W6+ were investigated. The Na3-xP1-xWxS4 sulfide-based solid electrolytes were prepared via a mechanochemical process and consecutive heat treatment. The Na2.85P0.85W0.15S4 electrolyte with Na vacancies exhibited an ionic conductivity of 8.8 x 10(-3) S cm(-1) at 25 degrees C, which was higher than that of Na3PS4 solid electrolyte. The all-solid-state batteries (Na-Sn/Na2.85P0.85W0.15S4/TiS2) exhibited a reversible capacity of 140 mA h g(-1) at a current density of 0.038 mA cm(-2) and retained the capacity of 115 mAh g(-1) for 40 cycles at 0.130 mA cm(-2) at 25 degrees C. The Na3-xP1-xWxS4 samples prepared via mechanochemistry are homogeneous electrolytes free of crystalline WS2 impurities and are effective for application to all-solid-state sodium batteries.

[发布日期] 2021-09-15

[关键词] Solid electrolytes;Sodium-ion conductors;Sulfide electrolytes;Mechanochemical technique;All-solid-state batteries