A sodium-ion sulfide solid electrolyte with unprecedented conductivity at room temperature.

Hayashi, A; Masuzawa, N; Yubuchi, S; Tsuji, F; Hotehama, C; Sakuda, A; Tatsumisago, M · Nat Commun · 2019

basic_science · Level V

Where this comes from

Abstract

Solid electrolytes are key materials to enable solid-state rechargeable batteries, a promising technology that could address the safety and energy density issues. Here, we report a sulfide sodium-ion conductor, Na<sub>2.88</sub>Sb<sub>0.88</sub>W<sub>0.12</sub>S<sub>4</sub>, with conductivity superior to that of the benchmark electrolyte, Li<sub>10</sub>GeP<sub>2</sub>S<sub>12</sub>. Partial substitution of antimony in Na<sub>3</sub>SbS<sub>4</sub> with tungsten introduces sodium vacancies and tetragonal to cubic phase transition, giving rise to the highest room-temperature conductivity of 32 mS cm<sup>-1</sup> for a sintered body, Na<sub>2.88</sub>Sb<sub>0.88</sub>W<sub>0.12</sub>S<sub>4</sub>. Moreover, this sulfide possesses additional advantages including stability against humid atmosphere and densification at much lower sintering temperatures than those (>1000 °C) of typical oxide sodium-ion conductors. The discovery of the fast sodium-ion conductors boosts the ongoing research for solid-state rechargeable battery technology with high safety, cost-effectiveness, large energy and power densities.