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All‐solid‐state Li–S batteries are a promising energy storage system that can solve the shuttle effects of polysulfides in liquid Li–S batteries. However, sluggish solid‐state reaction kinetics and the low conductivity of cathode materials have impeded their development. Here, a N‐doped carbon embedded with CuS nanoparticles (CuSNC) is reported as a host for Li2S in all‐solid‐state batteries that addresses some of these issues. Electrochemical studies, supported by a combination of X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), X‐ray absorption spectroscopy (XAS), electron microscopy, and density functional theory (DFT) calculations reveal that CuSNC provides good affinity to Li2S. This lowers the activation barrier for the conversion of Li2S to sulfur on the charge, suggesting an electrocatalytic effect on the CuS surface. Li+ diffusion in the cathode and the reaction kinetics are enhanced compared to N‐doped graphene. The CuSNC/Li2S cathode reaches an areal capacity of 1.8 mAh cm−2 and a retention rate of 94% after 100 cycles. At a 1.0 mA cm−2 current density, CuSNC/Li2S maintains stable performance over 500 cycles with a low decay rate (0.05% per cycle); at a higher Li2S loading, delivers a capacity of 9.6 mAh cm−2, albeit with more limited cycling. This study provides a promising way to design Li2S cathodes to achieve improved reaction kinetics and better electrochemical performance. [ABSTRACT FROM AUTHOR]

As demands for electrochemical energy storage continue to rise, alternative electrochemistries to conventional Li‐ion batteries become more appealing. Here, an intercalation‐conversion hybrid cathode that combines intercalation‐type VS2 with conversion‐type sulfur chemistry to construct high performance solid‐state lithium‐sulfur batteries is reported. The layered VS2 nanomaterial features Li‐ion transport channels, metallic conductivity, and active capacity contribution, all of which provide an ideal platform for the solid state S/Li2S redox couple to unlock its high gravimetric capacity. The S/VS2/Li3PS4 hybrid cathode composite is prepared by a facile, low‐cost, and low‐energy mechanical blending process. The S/VS2/Li3PS4|Li3PS4|Li/In (or Li) all‐solid‐state cell exhibits sulfur utilization of ≈85%, with a Coulombic efficiency of close to 100%. High areal capacity up to 7.8 mA h cm−2 with an active material loading (S/VS2) as high as 15.5 mg cm−2 is achieved. [ABSTRACT FROM AUTHOR]

A comprehensive approach is reported to construct stable and high volumetric energy density lithium-sulfur batteries, by coupling a multifunctional and hierarchically structured sulfur composite with an in-situ cross-linked binder. Through a combination of first-principles calculations and experimental studies, it is demonstrated that a hybrid sulfur host composed by alternately stacking graphene and layered graphitic carbon nitride embraces high electronic conductivity as well as high polysulfide adsorptivity. It is further shown that the cross-linked elastomeric binder empowers the hierarchical sulfur composites-multi-microns in size-with the ability to form crack-free and compact high-loading electrodes using traditional slurry processing. Using this approach, electrodes with up to 14.9 mg cm−2 sulfur loading and an extremely low electrolyte/sulfur ratio as low as 3.5: 1 µL mg−1 are obtained. This study sheds light on the essential role of multifaceted cathode design and further on the challenges facing lithium metal anodes in building high volumetric energy density lithium-sulfur batteries. [ABSTRACT FROM AUTHOR]

The lithium-sulfur battery is a compelling energy storage system because its high theoretical energy density exceeds Li-ion batteries at much lower cost, but applications are thwarted by capacity decay caused by the polysulfide shuttle. Here, proof of concept and the critical metrics of a strategy to entrap polysulfides within the sulfur cathode by their reaction to form a surface-bound active redox mediator are demonstrated. It is shown through a combination of surface spectroscopy and cyclic voltammetry studies that only materials with redox potentials in a targeted window react with polysulfides to form active surface-bound polythionate species. These species are directly correlated to superior Li-S cell performance by electrochemical studies of high surface area oxide cathodes with redox potentials below, above, and within this window. Optimized Li-S cells yield a very low fade rate of 0.048% per cycle. The insight gained into the fundamental surface mechanism and its correlation to the stability of the electrochemical cell provides a bridge between mechanistic understanding and battery performance essential for the design of high performance Li-S cells. [ABSTRACT FROM AUTHOR]