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Lithium–sulfur batteries (Li–S) are recognized as the next generation of secondary batteries due to their satisfactory theoretical specific capacity and energy density. However, a series of problems such as disordered migration behavior, sluggish redox kinetics, and serious shuttle effect of lithium polysulfides (LiPSs) greatly limit the commercial application. Herein, nanoreactors encapsulate heterostructure to guarantee sulfur conversion in the hosts where the heterostructure consists of FeP with moderate adsorption ability, excellent catalytic active and low work function, and Fe3O4 with strong adsorption ability and high work function. This rational configuration of heterostructure controls the direction of the interface built‐in electric field (BIEF) between catalyst and adsorbent, realizing the successive "trapping‐directional migration‐conversion" reaction mechanism to sulfur species. Thanks to BIEF as a bridge to connect the trapping site and catalytic site, Fe3O4/FeP@C─S cathode delivers an ultrahigh initial specific capacity of 1402 mAh g−1 at 0.1 C and remains more than 450 mAh g−1 at 5 C after 350 cycles. Even with a sulfur loading of 5.20 mg cm−2, it displayed the initial specific capacity of 970 mAh g−1. This work provided an effective strategy to design high‐performance electrocatalysts for commercial Li–S batteries. [ABSTRACT FROM AUTHOR]

The notorious "shuttle effect" of lithium polysulfides (LiPSs) has suppressed the large‐scale commercial application of lithium‐sulfur batteries (LSBs). Also, the intrinsic advantages including inhibiting the shuttling‐circulation and promoting the conversion of LiPSs, on the separator are deemed as stimulating blocks on the exploitation of LSBs. Herein, guided by theoretical calculations, we have designed doping‐heteroatoms boron (B) and phosphorus (P) on graphitic carbon nitride (g‐C3N4), to suppress the "shuttle effect" of LiPSs and improve the battery cycling performance. Theoretical calculations show strong chemical bonding between Li atom and N substance of g‐C3N4, and corroborates synergistic mechanism of electron transfer and van der Waals interaction. The high adsorption energies with doping B/P atoms enable LiPSs adsorption on the separators inhibiting shuttle loss. As expected, the experiment data also demonstrate that superior electrochemical performance are achieved by utilizing B‐doped g‐C3N4 (BCN) separator. Incorporating the B‐doped g–C3N4 (BCN) separator in LSBs delivered an initial specific capacity of 1050 mAh g−1 at 1 C and 920 mAh g−1 at 2 C. Notably, it achieved a decay rate of 0.08% and 0.1% at 1 and 2 C, respectively, after 500 cycles. This study furthers our understanding of B/P doping separator enhancement and restraining LiPSs shuttling loss for an improved LSBs performance. [ABSTRACT FROM AUTHOR]

The step‐order or disproportionation conversion of lithium polysulfides (LiPSs) is still a blind box in LiS batteries (LSBs) system. The cation‐doped electrocatalyst (Fe‐CoS2@HCNF) is designed through modulating electron‐surrounding situation of the central atomic d‐band to promote regional electron‐directed LiPSs reduced‐order‐transformation (especially, Li2S4Li2S). Fe‐CoS2@HCNF satisfies the requirement of mass (electron/ion) transfer reaction, quantizing as multi‐osmosis‐connected transportation channels and an all‐encompassing interior space for sulfur reduction occurring. Based on experiments and DFT calculations, the introduced Fe presents a local electron deficiency state toward regulating regional electron delocalization between Fe and Co matrix, which induces the d‐band state of the metal site, strengthening the metal 3d orbital coupling interaction with S2−of LiPSs, further guiding the order‐transformation of intermediate LiPSs. Consequently, the Fe‐CoS2@HCNF electrode has excellent electrochemical properties, performing at 3.0 C with 0.064 % capacity decay per cycle, and even maintaining super cycle stability at a high sulfur loadings. In addition, the pouch cell assembled can also reach an initial specific capacity of 1070.3 mAh g−1 at 0.1 C, which can still show good long‐term cycle stability. This work provides a valuable prospect for analyzing SRR intermediate state by regional electron flow regulation of electrocatalyst in practical LSBs. [ABSTRACT FROM AUTHOR]

Lithium–sulfur (Li–S) batteries have received tremendous attention due to their superior theoretical energy density of 2600 Wh kg−1, as well as the abundance of sulfur resources and its environmental friendliness. Polymer binders as an indispensable component in cathodes play a critical role in maintaining the structural integrity and stability of electrodes. Additionally, multifunctional polymer binders have been involved in Li–S batteries to benefit electrochemical performance by mitigating the shuttle effect, facilitating the electron/ion transportation, and propelling the redox kinetics. In the context of the significant impact of binders on the performance of Li–S batteries, recent progress in research on polymer binders in sulfur cathodes is herein summarized. Focusing on the functions and effects of the polymer binders, the authors hope to shed light on the rational construction of robust and stable sulfur cathode for high‐energy‐density Li–S batteries. Perspectives regarding the future research opportunities in Li–S batteries are also discussed. Polymer binders in lithium–sulfur batteries play a critical role in maintaining the structural integrity and stability of the electrode as an indispensable component. In this review, recent progress in research on polymer binders in sulfur cathodes is summarized, focusing on the rational design strategies of multifunctional polymer binders toward better lithium–sulfur batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • MoS 2 /Co 4 S 3 /C heterojunction is prepared by simple method as cathode host. • MoS 2 /Co 4 S 3 /C exhibits job-synergistic polysulfides adsorption-conversion. • MoS 2 /Co 4 S 3 /C/S reveals excellent rate performance and cycle stability under high current. Lithium–sulfur batteries are considered one of the most promising next-generation energy storage devices owing to their ultrahigh theoretical energy density and environmental friendliness. However, the sluggish electrode reaction kinetics of the sulfur cathode and shuttle effects of lithium polysulfide (LiPSs) restrict their active material utilization and cycling stability. Herein, a hollow, free-standing MoS 2 /Co 4 S 3 /C heterojunction was fabricated and employed as a cathode host for high-performance lithium–sulfur batteries (LSBs). The unique hollow nanostructured MoS 2 /Co 4 S 3 /C can achieve job-synergistic polysulfide adsorption-conversion, in which the conductive nitrogen-doped carbon framework facilitates rapid electron/ion diffusion; polar Co 4 S 3 species provide strong chemisorption capability and endow intrinsic catalytic sites towards LiPSs, and MoS 2 serves as a nanocrystal to accelerate the reaction dynamics. As a result, MoS 2 /Co 4 S 3 /C/S exhibited high reversible specific capacities at 2C and was maintained at 394 mAh g−1 after 1000 cycles, with a 0.04% capacity decay rate. Impressively, the high reversible specific capacities with high sulfur loading of 4.1 mg cm−2 were maintained at 906.7 mAh g−1. [ABSTRACT FROM AUTHOR]

Rechargeable lithium-sulfur (Li–S) batteries are regarded as one of the most promising emerging energy technology due to their high theoretical capacity and energy density. However, the shuttle effect from the weak adsorption, poor diffusion-transfer, and insufficient catalytic site restrains further applications. Herein, the yolk-double shells hierarchical N-doped carbon nanospheres (NCS@C-800) were designed as an electrochemical nanoreactor, the material consists of high-content N-doped core-shell carbon nanospheres and a highly graphitized outer carbon shell, which has a gradient of N content. The unique structure host has many advantages, such as huge internal voids, ordered pore structure, and high electrical conductivity. In addition to the introduction of the N element, which offered a large number of adsorption and catalytic sites. Therefore, the NCS@C-800 effectively addresses the three above primary issues for constructing high performance Li–S. The results show that at 500 cycles at 1 C, the as-prepared material is 649 mAh g−1, while at 1000 cycles at 2 C it is 400 mAh g−1, with ultra-low capacity decays of 0.055% and 0.051% per cycle, respectively. More importantly, with an increase in S loading up to 5.43 mg cm−2, it still maintained excellent cycling stability. This work offered an effective strategy for high-performance Li–S batteries. [Display omitted] •A "yolk-double shells" structured hierarchical N-doped carbon nanospheres were designed for high performance lithium-sulfur batteries; •Superior adsorption ability, excellent conductive carbon framework and intrinsic catalytic sites exist in unique yolk-double shells structure; •The S@NCS@C-800 exhibits 897 mAh g−1 at 1C, and shows excellent cycling stability even at 5.43 mg cm−2. [ABSTRACT FROM AUTHOR]

• Fe 3 C@NCNT is designed and prepared as a promoter for high performance Li-S batteries. • The effects are attributed to the synergy between NCNTs and Fe 3 C catalyst. • The composite material delivers an excellent initial capacity and cycling stability. [Display omitted] Rechargeable Lithium-Sulfur batteries (LSBs) are widely investigated as one of the most promising electrochemical energy storage devices due to their high energy density, low cost and environmental benignancy. However, poor conductivity, insufficient adsorption strength and sluggish multi-electron redox reactions restrict LSBs performance. Thus rational design of one–dimensional materials with good conductivity for sulfur, strong adsorption and catalytic abilities to lithium polysulfides (LiPSs), is necessary for improving the electrochemical behavior of lithium-sulfur batteries. Herein, we report Fe 3 C nanorods encapsulated in nitrogen-doped carbon nanotube (Fe 3 C@NCNT) as a promoter for sulfur cathode, in which CNT acting as a conductive network promotes ionic and electronic transfer, while "lithiophilic" heteroatom N immobilizes LiPSs through strong chemical bonding (Li–N bonds), and Fe 3 C accelerates the adsorption and conversion of LiPSs derived from its catalytic Fe 3 C site. Therefore, the Fe 3 C@NCNT as a promoter prolong the life of LSBs with the help of the synergistic effect of polarized N heteroatoms and catalytic effect of Fe 3 C. As a result, the composite cathode material delivers an outstanding initial capacity of 950 mAh g−1 at 0.5 C, and a capacity of 870 mAh g−1 after 100 cycles. This work proposes a feasible strategy to immobilize LiPSs and accelerate the conversion of LiPSs in high-performance lithium-sulfur batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • Rationally design CR-Por-PPIs with 3D structure as cathode hosts for Li-S batteries. • The materials were prepared with a simple and scalable method. • They have synergistic effects of trapping, chemisorption and catalysis on LiPSs. • The effects can be adjusted, such as the central coordination element (Cu, Co, Zn). The construction of three-dimensional (3D) microporous structure cathode host material used in lithium sulfur battery perfectly provides the combination advantages of good physical confinement and chemical immobilization to suppress polysulfide shuttling. Hence, the construction of advanced POPs-based sulfur cathode hosts with hierarchical pore channel, high pore volume, strong polar segments, and catalytic sites is significant and necessary. Herein, a series of crosslinked porphyrin-based porous polyimides (CR-Por-PPIs) with hierarchical structures were fabricated from porphyrin-based tetramine (TAPP), alkynyl dianhydride (PEPHQDA) and metal inorganic salt (Cu, Co, Ni, Pb, Zn) via polymerization and 360℃ treatment. Owing to the well-constructed porous skeleton architectures, CR-Por-PPIs provide hierarchical pore channels and sufficient pore cavities for trapping polysulfides and relieving volume expansion, afford considerable heteroatom N species for buffering shuttle behaviors via strong chemisorption interaction, endow porphyrin ring catalytic center and metal catalytic sites for enhancing redox kinetics. Profiting from the synergistic efforts, S/CR-Por-PPIs composites cathodes show improved long-term cycle capabilities and rate properties. Chelated metal (Cu, Co, Zn) S/CR-Por-PPIs have superior cycling stabilities due to the promoted catalytic property by virtue of the co-existence of porphyrin-ring catalytic center and metal catalytic sites. These findings can help to facilitate scalable acquisition of high-performance cathode materials for lihium-sulfur batteries, and promote their commercialization. [ABSTRACT FROM AUTHOR]