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All-solid-state batteries (ASSBs) with inorganic solid electrolytes (SEs) have received much attention as future energy storage systems owing to their high energy densities and excellent safety. Sulfide-based SEs are considered promising because they exhibit greater ionic conductivities and mechanical softness than oxide-based SEs. In particular, argyrodite-type Li6PS5Cl with a high ionic conductivity of 3.0 × 10−3 S cm−1 offers new possibilities for realizing high-performance ASSBs. However, contact with moisture results in the evolution of H2S from Li6PS5Cl, which has hindered the scalable fabrication and practical application of Li6PS5Cl. To avoid this issue, we propose incorporating a zeolite, which can act as a scavenger for both toxic H2S gas and moisture, as a functional additive in Li6PS5Cl. We demonstrate that zeolite-embedded Li6PS5Cl exhibits greatly improved chemical stability and reduced H2S evolution upon storage in humid air (RH 50%), leading to a noticeable improvement in the cycle performance of ASSBs. This approach could resolve the technical issues associated with sulfide-based SEs toward commercial-scale implementation. [ABSTRACT FROM AUTHOR]

Bulk-type all-solid-state Na-ion batteries (ASNBs) employing inorganic Na-ion conductors and operating at room temperature are considered as promising candidates for large-scale energy storage systems. However, their realization has been impeded by low ionic conductivity, instability in air of the solid electrolytes, and poor ionic contacts among the constituents of the electrodes. Here, we report novel glass-ceramic xNaI·(1 −x)Na3SbS4 superionic conductors (maximum Na+ conductivity of 0.74 mS cm−1 at 30 °C, for x = 0.10) obtained from scalable methanol solutions. Comprehensive spectroscopic evidence, density functional theory calculations, and electrochemical analysis suggest the decisive role of I− incorporated in the disordered domains at the nanoscale in the overall Na+ transport. Furthermore, the solution-derived NaI·Na3SbS4 forms uniform coating layers on the surface of the active material FeS2, providing unobstructed ionic transport pathways in the electrodes. The good electrochemical performance of FeS2/Na–Sn ASNBs at 30 °C is demonstrated. [ABSTRACT FROM AUTHOR]

Bulk-type all-solid-state Li-ion batteries have emerged as the enabler to achieve better safety and to use Li metal negative electrodes for higher energy density. However, all-solid-state half-cells fabricated using In or Li–In counter electrodes (CEs) have been routinely tested to assess working electrodes (WEs) without any verification. Moreover, there have been few reports on the in-depth analysis of all-solid-state full-cells, which is imperative for practical applications. In this work, for the first time, we report novel bulk-type all-solid-state three-electrode cells that enable successful deconvolution and diagnosis of the voltages of positive and negative electrodes even for cells having thin solid electrolyte (SE) layers. In the first case study, that of Sn/Li–In half-cells, earlier termination of Li–In CEs than Sn WEs, which results in unexpectedly low capacity, is measured. This problem is solved by percolating Li–In with SEs. For the second case, namely, that of LiNi0.6Co0.2Mn0.2O2/graphite full-cells having only 50–60 μm-thick SE layers (which are fabricated by a scalable wet-slurry process), internal short circuits by penetrating growth of Li metal during charging at high C-rates are revealed for the first time. Further, a unique dischargeability to 0 V for LiNi0.6Co0.2Mn0.2O2/graphite or LiNi0.6Co0.2Mn0.2O2/Si–C full-cells is described. [ABSTRACT FROM AUTHOR]

Room-temperature-operable all-solid-state Na-ion batteries (ASNBs) using sulfide Na-ion solid electrolytes (SEs) are promising because of their potential for greater safety, lower cost, and acceptable performance. Despite extensive developments in the area of sulfide Na-ion SEs, their poor chemical stability and prospects for wet-chemical synthesis have been overlooked to date. Herein, the scalable synthesis of Na3SbS4via aqueous-solution routes using precursors of Na2S, Sb2S3, and elemental sulfur for ASNBs is described. With no concerns about the evolution of toxic H2S gas, the aqueous-solution-synthesized Na3SbS4 exhibits high ionic conductivities (0.1–0.2 mS cm−1 at 25 °C). Importantly, the homogeneity of the aqueous solutions enables the creation of uniform Na3SbS4 coatings on FeS2. Fe2S/Na–Sn ASNBs, employing the aqueous-solution-synthesized Na3SbS4 and the Na3SbS4-coated FeS2 for the SE layer and positive electrode, respectively, demonstrate a high charge capacity of 256 or 346 mA h g−1 with good reversibility at 30 °C, highlighting their potential for practical applications. [ABSTRACT FROM AUTHOR]