Sulfide Na-ion solid electrolytes (SEs) are key to enable room-temperature operable all-solid-state Na-ion batteries that are attractive for large-scale energy storage applications. To date, few sulfide Na-ion SEs have been developed and most of the SEs developed contain P and suffer from poor chemical stability. Herein, discovery of a new structural class of tetragonal Na4−xSn1−xSbxS4 (0.02 ≤ x ≤ 0.33) with space group I41/acd is described. The evolution of a new phase, distinctly different from Na4SnS4 or Na3SbS4, allows fast ionic conduction in 3D pathways (0.2–0.5 mS cm−1 at 30 °C). Moreover, their excellent air stability and reversible dissolution in water and precipitation are highlighted. Specifically, TiS2/Na–Sn all-solid-state Na-ion batteries using Na3.75Sn0.75Sb0.25S4 demonstrates high capacity (201 mA h (g of TiS2)−1) with excellent reversibility.
Bibliographical noteFunding Information:
J.W.H., A.B., and K.H.P. contributed equally to this work. This work was supported by Basic Science Research Program (No. NRF-2017M1A2A2044501) and by Leading Foreign Research Institute Recruitment Program (No. NRF-2017K1A4A3015437) through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning, and by the Materials and Components Technology Development Program of MOTIE/KEIT (10076731).
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All Science Journal Classification (ASJC) codes
- Renewable Energy, Sustainability and the Environment
- Materials Science(all)