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Lithium-sulfur (Li-S) batteries have been recognized as promising substitutes for current energy-storage technologies owing to their exceptional advantage in energy density. The main challenge in developing highly efficient and long-life Li-S batteries is simultaneously suppressing the shuttle effect and improving the redox kinetics. Polar host materials have desirable chemisorptive properties to localize the mobile polysulfide intermediates; however, the role of their electrical conductivity in the redox kinetics of subsequent electrochemical reactions is not fully understood. Conductive polar titanium carbides (TiC) are shown to increase the intrinsic activity towards liquid-liquid polysulfide interconversion and liquid-solid precipitation of lithium sulfides more than non-polar carbon and semiconducting titanium dioxides. The enhanced electrochemical kinetics on a polar conductor guided the design of novel hybrid host materials of TiC nanoparticles grown within a porous graphene framework (TiC@G). With a high sulfur loading of 3.5 mg cm , the TiC@G/sulfur composite cathode exhibited a substantially enhanced electrochemical performance.

A cooperative interface constructed by "lithiophilic" nitrogen-doped graphene frameworks and "sulfiphilic" nickel-iron layered double hydroxides (LDH@NG) is proposed to synergistically afford bifunctional Li and S binding to polysulfides, suppression of polysulfide shuttles, and electrocatalytic activity toward formation of lithium sulfides for high-performance lithium-sulfur batteries. LDH@NG enables high rate capability, long lifespan, and efficient stabilization of both sulfur and lithium electrodes.

Lithium-sulfur batteries (Li-S) have attracted soaring attention due to the particularly high energy density for advanced energy storage system. However, the practical application of Li-S batteries still faces multiple challenges, including the shuttle effect of intermediate polysulfides, the low conductivity of sulfur and the large volume variation of sulfur cathode. To overcome these issues, here we reported a self-templated approach to prepare interconnected carbon nanotubes inserted/wired hollow CoS nanoboxes (CNTs/CoS-NBs) as an efficient sulfur host material. Originating from the combination of three-dimensional CNT conductive network and polar CoS-NBs, the obtained hybrid nanocomposite of CNTs/CoS-NBs can offer ultrahigh charge transfer properties, and efficiently restrain polysulfides in hollow CoS-NBs via the synergistic effect of structural confinement and chemical bonding. Benefiting from the above advantages, the S@CNTs/CoS-NBs cathode shows a significantly improved electrochemical performance in terms of high reversible capacity, good rate performance, and long-term cyclability. More remarkably, even at an elevated temperature (50 °C), it still exhibits high capacity retention and good rate capacity.

Favorable characteristics, such as high energy density, cost efficiency, and environmental benignity, render lithium–sulfur (Li–S) batteries a promising candidate to meet the increasing demand for efficient and economic energy‐storage systems. Many efforts have been devoted to and much progress has been achieved in Li–S‐battery research from both the scientific and technological viewpoints. Various tools, methods, and protocols have been developed for Li–S‐battery research. Here, these advancements are summarized, from spectroscopic to electrochemical techniques, and the landscape of Li–S chemistry is painted from reactions to transport phenomena. The aim is to provide a comprehensive toolbox for Li–S‐battery research and spur future development in multi‐electron chemistry, multiphase conversion, and related energy‐storage systems and fields.

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Surface reactions constitute the foundation of various energy conversion/storage technologies,s uch as the lithium-sulfur (Li-S) batteries.T oe xpedite surface reactions for high-rate battery applications demands in-depth understanding of reaction kinetics and rational catalyst design. Now an in situ extrinsic-metal etching strategy is used to activate an inert monometal nitride of hexagonal Ni 3 Nt hrough ironincorporated cubic Ni 3 FeN. In situ etched Ni 3 FeNr egulates polysulfide-involving surface reactions at high rates.E lectron microscopywas used to unveil the mechanism of in situ catalyst transformation. The Li-S batteries modified with Ni 3 FeN exhibited superb rate capability,r emarkable cycling stability at ah igh sulfur loading of 4.8 mg cm À2 ,a nd lean-electrolyte operability.T his work opens up the exploration of multimetallic alloys and compounds as kinetic regulators for highrate Li-S batteries and also elucidates catalytic surface reactions and the role of defect chemistry.

Preservation of cycling behavior Understanding the changes in interfaces between electrode and electrolyte during battery cycling, including the formation of the solid-electrolyte interphase (SEI), is key to the development of longer lasting batteries. Z. Zhang et al . adapt a thin-film vitrification method to ensure the preservation of liquid electrolyte so that the samples taken for analysis using microscopy and spectroscopy better reflect the state of the battery during operation. A key finding is that the SEI is in a swollen state, in contrast to current belief that it only contained solid inorganic species and polymers. The extent of swelling can affect transport through the SEI, which thickens with time, and thus might also decrease the amount of free electrolyte available for battery cycling. —MSL