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Lithium–sulfur batteries are deemed as optimal energy devices for the next generation of high‐energy‐density energy storage. However, several problems such as low energy density and short cycle life hinder their application in industry. Here, MoS2–MoN heterostructure nanosheets grown on carbon nanotube arrays as free‐standing cathodes are reported. In this heterostructure, MoN works as a promoter to provide coupled electrons to accelerate the redox reaction of polysulfides while the MoS2, with a two‐dimensional layered structure, provides smooth Li+ diffusion pathways. Through their respective advantages, both MoN and MoS2 could mutually boost the process of "adsorption‐diffusion‐conversion" of polysulfides, which have a synergy enhancement effect to restrain the lithium polysulfides from shuttling. The designed cathodes show excellent long‐term cycling performances of 1000 cycles at 1C with a low decay rate of 0.039% per cycle and a high rate capability up to 6C. A high initial areal capacity of 13.3 mAh cm−2 is also achieved under a low electrolyte volume/sulfur loading (E/S) ratio of 6.3 mL g−1. This strategy of promoting polysulfide conversion by heterostructure MoS2–MoN as presented in this work can provide a more structured design strategy for future advanced Li–S energy storage systems. [ABSTRACT FROM AUTHOR]

[Display omitted] In order to fundamentally suppress the shuttle effect, N 2 Plasma & Al 2 O 3 magnetron sputtered separators (Al 2 O 3 @ N -PP) are proposed for lithium-sulfur batteries (LSBs). Such a dual-functional polysulfides (LiPSs) barrier separator greatly inhibits the shuttle effect from the perspective of physical and chemical interaction. Physically, the inherently electronegative amorphous Al 2 O 3 first achieves the repulsion of LiPSs to the sulfur cathode through the electrostatic repulsive effect, effectively preventing a large amount of soluble LiPSs from accumulating at the separator. At the same time, the Al 2 O 3 film seals the shuttle channel of LiPSs to a certain extent. Chemically, N 2 plasma-doped N heteroatoms form a lithium bond with Li+ in LiPSs to achieve the first step chemical adsorption and anchoring of LiPSs. When the LiPSs reaches the amorphous Al 2 O 3 film, more stable chemical bonds are formed between Al3+ and S2−, Li+ and O2– to achieve more effective adsorption and anchoring of LiPSs. At 1C with a high sulfur loading up to 3–5 mg cm−2 the LSB contributes a specific charge capacity of 717.4 mAh g−1, with high retention rate up to 75.49 % after 450 cycles. The U-shaped electrolytic cell experiment and ultraviolet–visible spectrum experiment confirmed the LiPSs barrier function of the functional separator. [ABSTRACT FROM AUTHOR]

Lithium-sulfur battery (LSB) is considered a kind of potential energy storage systems on account of its high theoretical capacity (1675 mAh·g−1) and energy density (2500 Wh·Kg−1). However, poor ionic/electronic conductivity and annoying shuttle effects still need to be resolved. Here a highly flexible and highly conductive MXene (Ti 3 C 2 T x) interlayer with a sandwich structure is reported, the surface of which is a TiS 2 /TiO 2 heterostructure formed by vulcanized. In this framework, the role of TiO 2 nanoparticles is adsorbent to combine the lithium polysulfides (LiPSs), and the TiS 2 nanoparticles function as catalysts to further facilitate the conversion of long-chain LiPSs to short-chain Li 2 S 2 /Li 2 S under the high conductivity of Ti 3 C 2 T x. Furthermore, the interlayer can protect the Lithium metal anode by preventing polysulfide from depositing on the anode surface. Accordingly, the TOS/MX/TOS interlayer exhibits excellent performance with stable long-term cycling (≈76.1% capacity retention with a decay rate of 0.048% per cycle after 500 cycles at 1C). This sandwiched interlayer with high discharge capacity and steady cycling performances is conducive to the practical application of lithium-sulfur batteries. [Display omitted] [ABSTRACT FROM AUTHOR]

• Sulfur host prepared by a unique dual-channel electrospinning method. • WS 2 /WO 3 and MoS 2 /MoO 3 heterostructures enabling anchor of LiPSs. • WX 2 and MoX 2 realized LiPSs adsorption and catalytic conversion. • Excellent energy storage performance is in both coin cell and pouch cell. Due to the dissolution of Lithium polysulfides (LiPSs), the volume expansion, and poor conductivity, practical applications of Lithium-sulfur batteries (LSBs) are not satisfactory. Herein, dual-heterostructure decorated interweaved carbon nanofibers are proposed as sulfur hosts to significantly improve the energy storage behavior of LSBs. The unique structure of the interweaved carbon nanofibers and heterostructures provides more transmission channels for electrons and ions while also accelerating the process. Moreover, the heterostructures induce chemical anchoring and catalytic conversion of LiPSs. As a result, the cathode in the coin cell delivers an initial capacity of 777.9 mAh g−1 at 1C and high retention of 68.59% after 600 cycles. In the pouch cell, the cathode delivers a discharge capacity of 907.8 mAh g−1 and a reversible charging capacity of 913.1 mAh g−1 for the first cycle with an ultra-high sulfur loading up to 9.136 mg cm−2. Beyond that, density functional theory calculations, X-ray photoelectron spectroscopy, symmetric cell, and Li 2 S nucleation tests were adopted to verify the adsorption and catalytic conversion mechanisms of the cathode. This excellent interweaved dual-heterostructure sulfur host provides a novel structural design strategy for efficient chemical adsorption and catalytic conversion of LiPSs, as well as more opportunities for the commercial application of LSBs. [ABSTRACT FROM AUTHOR]