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All‐solid‐state sodium ion batteries (ASSIBs) attract growing attention as the next generation of batteries due to their high energy density, excellent safety, and the abundance of sodium resources. As a vital component of ASSIBs, chalcogenide Na‐ion solid‐state electrolytes (SSEs) have been widely studied due to their high ionic conductivity and outstanding ductility. However, due to the susceptibility to organic solvents and moisture, no chalcogenide Na‐ion SSEs membrane has been reported while only thick SSEs pellets have been investigated, which introduces abundant "dead" weight and lowers the energy density of ASSIBs. Herein, utilizing the excellent air stability of Na3SbS4, a thin (∼220 μm) Na3SbS4 membrane is prepared in air via a facile dry‐film method with polytetrafluoroethylene fibrillation, which exhibits a high ionic conductivity of 0.19 mS cm and an excellent critical current density of 0.6 mA/cm2. In summary, the chalcogenide Na‐ion SSEs membranes with high ionic conductivity and the simple preparation process could be readily adopted by pragmatic high‐performance ASSIBs. [ABSTRACT FROM AUTHOR]

Chalcogenides with high ionic conductivity and appropriate mechanical properties are promising solid‐state electrolytes (SSEs) to substitute current liquid electrolytes in lithium‐ion batteries. Yet, their practical applications in all‐solid‐state batteries are still retarded by both the low critical current density and the inferior interfacial stability toward electrodes. In this work, a series of superior SSEs, that is, Li2S‐P2S5‐B2S3 electrolytes, are developed via a ball‐milling and then melt‐quenching strategy. These SSEs exhibit a high critical current density of 1.65 mA cm−2 and a long cycling life of over 300 h. In addition, the evolution mechanism of the interphase between SSEs and metallic lithium is revealed via operando electrochemical impedance spectroscopy, depth‐profiling XPS, and in situ Raman spectroscopy. The structural and chemical heterogeneities are found to be the main origins of the continual interphase evolution. The resulting "multi‐layer mosaic like" interphase facilitates the suppression of Li dendrite growth, and hence, prolongs the lifetime of lithium‐ion all‐solid‐state batteries. In addition, the preparation technique of SSEs developed in the present work is feasible for scale‐up production. [ABSTRACT FROM AUTHOR]

Chalcogenide solid‐state electrolytes (SSEs) have been receiving growing attentions due to their high ionic conductivity and suitable mechanic properties, especially the Li2S–P2S5 systems incorporated with a second glass network formers (Si, Ge, Sn, and so on) besides P. Although the ionic conductivities are generally enhanced with the second glass network formers, the comprehensive effects of different glass formers on other properties, including electrochemical, cycling, and air stability, remain elusive. To acquire deeper understanding, herein, three common but representative glass network formers (SiS2, GeS2, and SnS2) were introduced into Li2S–P2S5, and their individual effects were investigated systematically. The results of multiscale characterizations before and after lithium stripping/plating cycling confirmed that the introduction of metal cations (Ge, Sn) generally leads to worse electrochemical stability and shorter cycle life of these SSEs toward lithium metal compared with SSEs with nonmetal cation (Si) modification. However, the air stability is related to the binding energy of M–S (M = Si, Ge, Sn), which is consistent with the hard base soft acid theory. This work provides valuable understanding for designing pragmatic Li2S–P2S5–MS2‐based SSEs with high electrochemistry, cycling, and air stability. [ABSTRACT FROM AUTHOR]

Chalcogenide solid states electrolytes (SSEs) are considered as one of the most promising alternative to replace liquid electrolytes for their high ionic conductivity and appropriate mechanical properties. However, the commercial applications of chalcogenide SSEs in all-solid lithium-ion batteries (ASSIBS) are still limited by the inferior interfacial stability, which leads to lithium dendrite growth and continual interphase formation. Here, the interfacial stability of Li 2 S–P 2 S 5 –B 2 S 3 SSEs have been enhanced effectively via LiI incorporation. In detail, a series of (100- x) (75Li 2 S–15P 2 S 5 –10B 2 S 3)- x LiI (x = 0, 5, 15, 30, 40) SSEs are prepared via ball-milling and then melt-quenching, which exhibit a high ionic conductivity of 1.53 mS cm−1 and a steady long cycling life up to 1637 h without obvious resistance growth at 0.1 mA cm−2. This excellent cycle life is originated from the electronic insulation interphase containing LiI without unaltered the "multi-layer mosaic like" structure of Li 2 S–P 2 S 5 –B 2 S 3 ternary glass system. In addition, this work also confirmed that LiI can act as a catalyst to enhance the charge transfer kinetics within S composite electrode thereby reducing the interface impedance. The stable interface performance obtained by this work could facilitate the development of ASSIBS with prolonged cycle life. [ABSTRACT FROM AUTHOR]

Among the chalcogenide solid-state electrolytes (SSEs), Na 3 SbS 4 is of particular importance because of its high ionic conductivity and compatibility with moist air, which reduces processing costs and favors large-scale industrial deployment. However, the cation doping effects on the electrochemical properties of the Na 3 SbS 4 remain elusive. Here, a series of Na (3-2x) Sb (1-x) Mo x S (4-x) I x (x = 0.05, 0.1 0.15, 0.2) SSEs were fabricated via the ball milling and melt quenching strategy. The valence state of Mo is revealed to be 4+ not 6+. A high ionic conductivity of 0.54 mS cm−1 and an excellent critical current density of 1.5 mA cm−2 was obtained at room temperature. The cycling life of the symmetric cell is up to 112 h. The as-prepared SSEs also exhibit outstanding chemical stability. This work provides insightful understanding of the valence state of cations and impacts on the electrochemical performance of chalcogenide SSEs, which are vital for designing optimal SSEs. [ABSTRACT FROM AUTHOR]