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Though polyvinylidene fluoride (PVDF) is widely‐used binder for conventional lithium‐sulfur (Li–S) batteries, it still encounters challenges of severe electrode fracture involved by drastic volume change upon repeating cycling, and lack of extended‐functions like trapping dissolved polysulfides and smoothing Li+ transfer. Herein, a methodology of grafting sulfophilic hydrogen‐bond donor and lithiophilic hydrogen‐bond acceptor to the polymer binder (named as PIL), function as gear teethes and tooth spaces, is reported. When cracks occur, the engaged gears driven by dynamic hydrogen bonds are separated, which are spontaneously reformed owing to the automatic meshing of gears, and thus accelerate the healing of cracks. At the molecular level, the synergetic effect of sulfophilic hydrogen‐bond donor and lithiophilic hydrogen‐bond acceptor enables polysulfides immobilization through "push‐pull effect", facilitating the subsequent redox kinetics. Accordingly, the cross‐link network of hydrogen bonds endows the elaborated designed polymer binder with strong adhesive strength and rapid Li+ migration. Attributed to these beneficial properties, the PIL‐based sulfur cathode exhibits excellent rate performance and superior cycling durability (an ultralow capacity fading rate of 0.062% per cycle over 800 cycles at 2 C). Even with high sulfur loading of 9.27 mg cm−2, a high areal capacity of 8.71 mAh cm−2 can be achieved, verifying its potential application. [ABSTRACT FROM AUTHOR]

Lithium‐sulfur batteries (LSBs) have recently gained extensive attention due to their high energy density, low cost, and environmental friendliness. However, serious shuttle effect and uncontrolled growth of lithium dendrites restrict them from further commercial applications. As "the third electrode", functional separators are of equal significance as both anodes and cathodes in LSBs. The challenges mentioned above are effectively addressed with rational design and optimization in separators, thereby enhancing their reversible capacities and cycle stability. The review discusses the status/operation mechanism of functional separators, then primarily focuses on recent research progress in versatile separators with purposeful modifications for LSBs, and summarizes the methods and characteristics of separator modification, including heterojunction engineering, single atoms, quantum dots, and defect engineering. From the perspective of the anodes, distinct methods to inhibit the growth of lithium dendrites by modifying the separator are discussed. Modifying the separators with flame retardant materials or choosing a solid electrolyte is expected to improve the safety of LSBs. Besides, in‐situ techniques and theoretical simulation calculations are proposed to advance LSBs. Finally, future challenges and prospects of separator modifications for next‐generation LSBs are highlighted. We believe that the review will be enormously essential to the practical development of advanced LSBs. [ABSTRACT FROM AUTHOR]

Despite concerns regarding safety, economics, and the environment, lithium-ion batteries (LIBs) are considerably utilized on account of their low energy density and capacity. Li–sulfur (Li–S) batteries have become a promising substitute for LIBs. Here, we first compared both systems in their cons and pros and analyzed the leading countries and companies in Li–S research are assessed through the utilization of an academic database. The scope of our research includes performance-enhancing design elements, cathode components, and binder materials. Synthetic and natural binders are trialed in an effort to enhance Li–S performance. Understanding the fundamental mechanisms enables the development of durable cathodes and binders. To overcome obstacles such as polysulfide adsorption, shuttle effect, and ion transport limitations, conducting polymers, metal/metal oxides, carbon-based compounds, MOFs, and Mxenes are investigated as potential cathode materials. In addition to pore characteristics and active polar sites, the efficacy of a battery is influenced by the anode surface geometry and heteroatom doping. Our review indicates that binders and sulfur/host composites must be meticulously chosen for Li–S battery cathode materials. This research advances energy storage technology by establishing the foundation for economically viable lithium–sulfur batteries with superior performance. [ABSTRACT FROM AUTHOR]

Lithium‐sulfur batteries (LSBs) have become one of the most powerful candidates for next‐generation battery technologies due to their high theoretical energy density and low cost. However, the notorious shuttle effect of soluble lithium polysulfides (LiPSs) and sluggish conversion reaction kinetics cause low sulfur utilization and inferior cycle life. Rational catalyst design on hierarchical pore structures and composition optimization is highly desired to realize synergetic enrichment, accommodation, and catalytic redox capacity of sulfur species. In this consideration, the hollow and porous N‐doped carbon framework is prepared, in which Co nanoparticles (NPs) are evenly embedded (denoted as Co‐HMCF) to modulate electron cloud density of carbons. Electrochemical tests and density functional theory (DFT) calculations demonstrate that Co‐HMCF could simultaneously deliver superior catalytic activity in accelerating LiPSs conversion as well as Li2S nucleation/decomposition to improve overall sulfur redox kinetics. Consequently, the Co‐HMCF interlayer significantly improves the battery performance, including high discharge capacity output (1538 mAh g−1 at 0.2 C), stable long‐term cycle (0.047% capacity decay per cycle for 800 cycles at 1.0 C), and exceptional rate capacity (582 mAh g−1 at 5.0 C). [ABSTRACT FROM AUTHOR]

Lithium‐sulfur (Li‐S) batteries offer promising prospects due to their high energy density and cost‐effectiveness. However, the sluggish kinetics of lithium polysulfides (LiPSs) conversion, particularly the crucial stage from LiPSs to lithium sulfide (Li2S), hampers their development. Herein, a novel strategy for dynamically regulating LiPSs conversion by incorporating 4‐mercaptopyridine (4Mpy), as a LiPSs Redox Regulator (RR) in the electrolyte is introduced. This organic sulfur additive actively interacts with LiPSs during discharge, facilitating rapid conversion and promoting the formation of a three‐dimensional (3D) Li2S structure, thereby enhancing reaction kinetics. Both theoretical and experimental results reveal that the redox conversion mechanism with the 4Mpy additive differs from traditional electrolytes. Upon lithiation, 4Mpy forms lithium‐pyridinethiolate (Li‐pyS), which reversibly engages in the LiPSs conversion during the charging/discharging cycles, significantly improving the redox process. As a result, the Li‐S battery with 4Mpy additive demonstrates superior performances, achieving 10.05 mAh cm−2 under a high sulfur loading of 10.88 mg cm−2, surpassing industrial benchmarks. This study not only presents an approach to mitigating the shuttle effect in Li‐S batteries but also offers valuable insights into electrolyte design for other metal batteries. [ABSTRACT FROM AUTHOR]

Recently, research on polyoxometalates (POMs) has gained significant momentum. Owing to their properties as electronic sponges, POMs catalyst harbor substantial potential in lithium‐sulfur battery research. However, POMs undergo a transformation into reduced heteropoly blue (HPB) during electrochemical reactions, which then dissolve into the electrolyte, resulting in catalyst loss. In this research, we amalgamated 18‐crown‐6 (CR6) with K3PW12O40, (KPW), synthesized a novel POM‐based supramolecular compound, and integrated it with graphene oxide (GO) to fabricate a multi‐functional composite polypropylene (PP) separator KPW‐CR6/GO/PP. The crown ether array was employed to immobilize POM and construct ion transport channels, thereby enhancing the Li+ migration rate and capturing polysulfides. Subsequently, leveraging the stable structure and redox properties of POM, the polysulfide is catalyzed to transform and inhibit the shuttle effect, thereby protecting the Li anode. The lithium‐sulfur batteries with the Crown ether‐POM supramolecular compound separators, exhibit enhanced capacity and stability (1073.3 mAh g−1 at 1.0 C, and 81.5 % retention rate after 250 cycles). The battery (S loading: 3.2 mg cm−2) presents an initial specific discharge capacity of 543.4 mAh g−1 at 0.5 C, with 89.8 % of the capacity retained after 160 cycles. This underlines the practical application potential of Crown ether‐POM supramolecular materials in Li−S batteries. [ABSTRACT FROM AUTHOR]

Improving the slow redox kinetics of sulfur species and shuttling issues of soluble intermediates induced from the multiphase sulfur redox reactions are crucial factors for developing the next‐generation high‐energy‐density lithium‐sulfur (Li−S) batteries. In this study, we successfully constructed a novel molecular electrocatalyst through in situ polymerization of bis(3,4‐dibromobenzene)‐18‐crown‐6 (BD18C6) with polysulfide anions on the cathode interface. The crown ether (CE)‐based polymer acts as a spatial "fence" to precisely control the unique redox characteristics of sulfur species, which could confine sulfur substance within its interior and interact with lithium polysulfides (LiPSs) to optimize the reaction barrier of sulfur species. The "fence" structure and the double‐sided Li+ penetrability of the CE molecule may also prevent the CE catalytic sites from being covered by sulfur during cycling. This new fence‐type electrocatalyst mitigates the "shuttle effect", enhances the redox activity of sulfur species, and promotes the formation of three‐dimensional stacked lithium sulfide (Li2S) simultaneously. It thus enables lithium‐sulfur batteries to exhibit superior rate performance and cycle stability, which may also inspire development facing analogous multiphase electrochemical energy‐efficient conversion process. [ABSTRACT FROM AUTHOR]

Fluoride ion batteries (FIBs) are regarded as one of the most promising candidates for next‐generation energy storage systems to achieve lower cost and higher energy density. However, the appropriate electrolyte design strategy is still lacking for FIBs to simultaneously settle the issues of fluoride salt dissolution and metal cation shuttle. Herein, a novel fluoride ion shuttle electrolyte with the synergistic high‐donor solvent (N, N‐dimethylacetamide, DMA) and alcohol anion acceptor (benzyl alcohol, BA) is developed. BA enables the promotion of solubility of inorganic fluoride salt (CsF). Meanwhile, benefiting from the re‐configuration of hydrogen bonding network by DMA, the solvation structures of anions and cations are regulated with reduced hindrance to F− shuttle and mitigated dissolution of active material. This electrolyte formation achieves superior interfacial stability with cathode, high F− conductivity (2.05 mS cm−1), and transference number (0.53). After matching CuF2 cathode and Pb anode, the full cell exhibits the highly reversible conversion reaction process with an initial discharge capacity of 300.8 mAh g−1 and a reversible capacity of 245.5 mAh g−1 after 43 cycles. This study proposes a solution to high‐performance rechargeable FIBs at room temperature by synergistically manipulating the anionic and cationic solvation chemistry. [ABSTRACT FROM AUTHOR]

The photo‐assisted strategy is regarded as a crucial approach to enhance the conversion kinetics of polysulfides in lithium–sulfur (Li–S) batteries. However, the development of photo‐assisted Li–S batteries still faces important challenges, such as the rapid recombination of photogenerated electron−holes on cathode and more severe shuttle effect. Herein, a breakthrough in overcoming the challenges has been made by constructing a promising photo‐assisted Li−S battery based on semiconducted metal−organic frameworks. During the discharging progress, the photoexcited electrons generated by H2BPDC ligand based on ligand‐to‐metal charge transfer (LMCT) effect, are injected into the Ti‐oxo clusters in Ti‐MOF, thereby facilitating the sulfur reduction to Li2S. And photoexcited holes are capable of promoting the decomposition kinetics of Li2S during charging. More importantly, the stronger chemical interaction between Ti‐BPDC‐d and polysulfides under light inhibits the polysulfides dissolution and shuttling, which fundamentally addresses the issue of light‐accelerated shuttling. As a result, the photo‐assisted Li–S batteries deliver a reversible capability of 1090.21 mAh g−1 at 0.2 C with a capacity retention of 82.91% over 150 cycles, and a superior rate capability of 673.58 mAh g−1 at 5 C. The findings are promising in advancing the design principles for photo‐rechargeable Li−S batteries. [ABSTRACT FROM AUTHOR]

Lithium‐sulfur batteries (LiSBs) with high energy density still face challenges on sluggish conversion kinetics, severe shuttle effects of lithium polysulfides (LiPSs), and low blocking feature of ordinary separators to LiPSs. To tackle these, a novel double‐layer strategy to functionalize separators is proposed, which consists of Co with atomically dispersed CoN4 decorated on Ketjen black (Co/CoN4@KB) layer and an ultrathin 2D Ti3C2Tx MXene layer. The theoretical calculations and experimental results jointly demonstrate metallic Co sites provide efficient adsorption and catalytic capability for long‐chain LiPSs, while CoN4 active sites facilitate the absorption of short‐chain LiPSs and promote the conversion to Li2S. The stacking MXene layer serves as a microscopic barrier to further physically block and chemically anchor the leaked LiPSs from the pores and gaps of the Co/CoN4@KB layer, thus preserving LiPSs within efficient anchoring‐conversion reaction interfaces to balance the accumulation of "dead S" and Li2S. Consequently, with an ultralight loading of Co/CoN4@KB‐MXene, the LiSBs exhibit amazing electrochemical performance even under high sulfur loading and lean electrolyte, and the outperforming performance for lithium‐selenium batteries (LiSeBs) can also be achieved. This work exploits a universal and effective strategy of a double‐layer functionalized separator to regulate the equilibrium adsorption‐catalytic interface, enabling high‐energy and long‐cycle LiSBs/LiSeBs. [ABSTRACT FROM AUTHOR]

Cationic lithium polysulfides (LiPSs) within ether‐based electrolytes are essential intermediates pivotal in instigating the shuttle effect. Suppressing the generation of cationic LiPSs is crucial for enhancing the performance of high‐energy‐density Li‐S batteries in practical applications. Herein, for the first time, it is demonstrated that cobalt phthalocyanine (CoPc) can significantly enhance the dissociation of LiPSs, leading to a decrease in cationic LiPSs species within the electrolyte. Employing NMR and in‐situ Raman spectroscopy, it is observed that CoPc interacts with sulfur anions within LiPSs, modifying the dissociation equilibrium of LiPSs in 1,2‐dimethoxyethane (DME)/1,3‐dioxolane (DOL) electrolyte. This CoPc‐mediated shift toward dissociation equilibrium reduces the concentration of cationic LiPSs, effectively suppressing the electromigration of LiPSs intermediates toward the Li anode during the charging process of Li‐S battery. As a result, the Li‐S battery enabled a high reversible areal capacity of 4.2 mAh cm−2 at a high sulfur loading of 5.0 mg cm−2 and a low electrolyte/sulfur (E/S) ratio of 3 µL mgs−1. This work affords a promising strategy for tackling the fundamental challenges regarding Li‐S batteries. [ABSTRACT FROM AUTHOR]

The 1T-rich MoS 2 @PC materials were rationally constructed and evaluated as an efficient polysulfide promotor for high-performance Li-S batteries. The constructed 1T-rich MoS 2 nanosheets not only have strong adsorption capacity for polysulfide, but also can catalyze the conversion of polysulfide rapidly. [Display omitted] The practical applications of lithium-sulfur (Li-S) batteries have severely been hindered by notorious shuttle effect and sluggish redox kinetics of lithium polysulfide intermediates (LiPSs), which bring about rapid capacity degradation, low coulombic efficiency and poor cycling stability. In this work, 1T-rich MoS 2 nanosheets are in-situ developed onto the conductive porous carbon matrix (1T-rich MoS 2 @PC) as efficient polysulfide promotors for high-performance Li-S batteries. The porous carbon skeleton tightly anchors MoS 2 nanosheets to prevent their reaggregation and ensures accessible electrical channels, and at the same time provides a favorable confined space that promotes the generation of 1T-rich MoS 2 structure. More importantly, the uniformly distributed metallic 1T-rich MoS 2 nanosheets not only affords rich sulfphilic sites and high binding energy for immobilizing LiPSs, but also favors rapid electron transfer and LiPSs conversation kinetics, substantially regulating sulfur chemistry in working cells. Consequently, the Li-S cell assembled with 1T-rich MoS 2 @PC modified separator delivers a remarkable cycling stability with ultralow capacity decay rate of 0.067% over 500 cycles at 1C. Encouragingly, under harsh conditions (high sulfur loading of 4.78 mg cm−2 and low E/S ratio of 8 μL mg−1), a favorable electrochemical performance can still be demonstrated. This study highlights the profitable design of 1T-rich MoS 2 /carbon based electrocatalyst for suppressing shuttle effect and promoting catalytic conversation of LiPSs, and has the potential to be applied to in other energy storage systems. [ABSTRACT FROM AUTHOR]

Shuttle effect of lithium polysulfides in lithium sulfur batteries greatly influenced their commercialization. Therefore, it is urgent to develop a cheep and effective way to alleviate the shuttle effect. Fe is an active transition element which has good catalytic ability, in this work, a simple wet impregnation method was used to make Fe ions infiltrate into the pores of BP2000 (a kind of commercial conductive carbon), then it was calcined in N2 atmosphere to get a Fe2O3/BP2000 composite and used as a separator modification layer. The Fe2O3 nano particles were decorated in the pores of BP2000 which greatly enhanced the absorption ability on lithium polysulfides, additionally it also showed excellent catalytic effect on lithium polysulfides, thus the Fe2O3/BP2000 layer can be served as a secondary collector to re-engage the polysulfides in the cathode reaction. In this way, the lithium sulfur batteries equipped with the Fe2O3/BP2000 modified separator showed impressive electrochemical performances. [ABSTRACT FROM AUTHOR]

To improve the sulfur reaction kinetics and inhibit the notorious shuttle effects, a tube‐in‐tube structure decorated by carbon nanotubes (CNT) and Fe3C nanoparticles (TIT/Fe3C‐CNT) is designed as sulfur host for lithium‐sulfur batteries (LSBs) in this work. The construction of tube‐in‐tube structure increases the active sites and the specific surface area of the material. Additionally, Fe3C nanoparticles can effectively adsorb the soluble lithium polysulfides and promote their catalytic conversion, thus greatly alleviating the shuttle effects. As a result of these advantages, the TIT/Fe3C‐CNT‐based cathode exhibits a high reversible capacity of 841 mAh g−1 after 200 cycles with a low decay of 0.056 % per cycle at 0.5 C. This work provides a promising and reasonable approach to the rational design of sulfur host for LSBs. [ABSTRACT FROM AUTHOR]

Lithium-sulfur (Li-S) batteries are a promising option for energy storage due to their theoretical high energy density and the use of abundant, low-cost sulfur cathodes. Nevertheless, several obstacles remain, including the dissolution of lithium polysulfides (LiPS) into the electrolyte and a restricted operational temperature range. This manuscript presents a promising approach to addressing these challenges. The manuscript describes a straightforward and scalable in situ thermal polymerization method for synthesizing a quasi-solid-state electrolyte (QSE) by gelling pentaerythritol tetraacrylate (PETEA), azobisisobutyronitrile (AIBN), and a dual salt lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and lithium nitrate (LiNO3)-based liquid electrolyte. The resulting freestanding quasi-solid-state electrolyte (QSE) effectively inhibits the polysulfide shuttle effect across a wider temperature range of −25 °C to 45 °C. The electrolyte's ability to prevent LiPS migration and cluster formation has been corroborated by scanning electron microscopy (SEM) and Raman spectroscopy analyses. The optimized QSE composition appears to act as a physical barrier, thereby significantly improving battery performance. Notably, the capacity retention has been demonstrated to reach 95% after 100 cycles at a 2C rate. Furthermore, the simple and scalable synthesis process paves the way for the potential commercialization of this technology. [ABSTRACT FROM AUTHOR]

Lithium–sulfur (Li–S) battery is a promising next‐generation energy storage system. However, the poor cyclability caused by the shuttle effect is still a key challenge for its practical application. Here, a polypropylene separator modified with α‐MnO2/RuO2 heterostructure is presented to facilitate the transformation of lithium polysulfides (LiPSs) and optimize the rate‐determining step in both the reduction and oxidation processes of the sulfur electrode. The unique separator effectively suppresses the dissolution and shuttling of soluble LiPSs in Li–S batteries. The α‐MnO2/RuO2 heterostructure modified separator with a Ru content of ≈8 wt% enables a high areal capacity of over 5.0 mAh cm−2 after 55 cycles at 0.2C in a Li–S coin cell, and the resultant pouch cell retains 78.2% of its initial capacity after 200 cycles at 0.1C, suggesting considerable potential for commercial applications. This work provides new insights into the regulation of electrochemical reactions in Li–S batteries. [ABSTRACT FROM AUTHOR]

The "shuttle effect" issue severely hinders the practical application of lithium–sulfur (Li–S) batteries, which is primarily caused by the significant accumulation of lithium polysulfides in the electrolyte. Designing effective catalysts is highly desired for enhancing polysulfide conversion to address the above issue. Here, the one‐step flash‐Joule‐heating route is employed to synthesize a W‐W2C heterostructure on the graphene substrate (W‐W2C/G) as a catalytic interlayer for this purpose. Theoretical calculations reveal that the work function difference between W (5.08 eV) and W2C (6.31 eV) induces an internal electric field at the heterostructure interface, accelerating the movement of electrons and ions, thus promoting the sulfur reduction reaction (SRR) process. The high catalytic activity is also confirmed by the reduced activation energy and suppressed polysulfide shuttling by in situ Raman analyses. With the W‐W2C/G interlayer, the Li–S batteries exhibit an outstanding rate performance (665 mAh g−1 at 5.0 C) and cycle steadily with a low decay rate of 0.06% over 1000 cycles at a high rate of 3.0 C. Moreover, a high areal capacity of 10.9 mAh cm−2 (1381.4 mAh g−1) is obtained with a high area sulfur loading of 7.9 mg cm−2 but a low electrolyte/sulfur ratio of 9.0 µL mg−1. [ABSTRACT FROM AUTHOR]

The practical application of lithium‐sulfur batteries with high theoretical energy density and readily available cathode active materials is hampered by problems such as sulfur insulation, dramatic volume changes, and polysulfide shuttling. The targeted development of novel binders is the most industrialized solution to the problem of sulfur cathodes. Herein, an aqueous conductive emulsion binder with the sulfonate‐containing hard elastic copolymer core and the conjugate polymer shell, which is capable of forming a bicontinuous mesoscopic interpenetrating polymer network, is synthesized and investigated. Not only can the elastic skeleton formed by the copolymer bind the active substance under drastic volume changes, but also the rich ester and cyanide groups in it can effectively capture lithium polysulfide. Meanwhile, the conducting skeleton consisting of poly(3,4‐ethylenedioxythiophene) both provides the additional charge conduction pathways and acts as the redox intermediates, significantly accelerating the kinetic process of lithium polysulfide conversion. Based on the synergistic effect of the above mechanisms, the use of the prepared binder on the sulfur carbon cathode significantly improves the rate performance and cycle stability of lithium sulfur batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] The high theoretical energy density and specific capacity of lithium-sulfur (Li-S) batteries have garnered considerable attention in the prospective market. However, ongoing research on Li-S batteries appears to have encountered a bottleneck, with unresolved key technical challenges such as the significant shuttle effect and sluggish reaction kinetics. This investigation explores the catalytic efficacy of three catalysts for Li-S batteries and elucidates the correlation between their structure and catalytic impacts. The results suggest that the combined utilization of lithium-insertion technology and a proton exchange approach for δ-MnO 2 can optimize its electronic structure, resulting in an optimal catalyst (H/Li inserted δ-MnO 2 , denoted as HLM) for the sulfur reduction reaction. The replacement of Mn sites in δ-MnO 2 with Li atoms can enhance the structural stability of the catalyst, while the introduction of H atoms between transition metal layers contributes to the satisfactory catalytic performance of HLM. Theoretical calculations demonstrate that the bond length of Li 2 S 4 adsorbed by the HLM molecule is elongated, thereby facilitating the dissociation process of Li 2 S 4 and enhancing the reaction kinetics in Li-S batteries. Consequently, the Li-S battery utilizing HLM as a catalyst achieves a high areal specific capacity of 4.2 mAh cm−2 with a sulfur loading of 4.1 mg cm−2 and a low electrolyte/sulfur (E/S) ratio of 8 μL mg−1. This study introduces a methodology for designing effective catalysts that could significantly advance practical developments in Li-S battery technology. [ABSTRACT FROM AUTHOR]

Lithium–Sulfur (Li─S) batteries are renowned for their high theoretical specific capacity and cost‐effectiveness. Nevertheless, their performance could be impeded by obstacles including lithium dendrite growth and lithium polysulfide (LiPS) shuttle, particularly under harsh conditions. Herein, an economical strategy is reported for modifying polyolefin separators (PP) with covalent organic polymer networks (TPE) to alter Li solvent structure, enhance lithium‐ion transport, and suppress shuttle effects. Combining in situ/ex situ characterization and theoretical calculations, it is demonstrated that the lithiophilic groups (‐C═N‐) in the TPE@PP separator form strong interaction with lithium, facilitating the dissociation of Li─Solvent/LiPS‐solvent to release freer lithium ion and shape a stable solid electrolyte interface rich in LiF and Li3N. The polymer network serves as a "highway" that accelerates Li transport and promotes uniform nucleation behavior. Therefore, the Li|TPE@PP|CNT/S cell enables 60% capacity retention after 2000 cycles at 1.0 C and exhibits stable cycling performance of 100 cycles from ‐40 to 80 °C. Moreover, the pouch cell maintains a capacity of more than 600 mA h g−1 after 30 cycles at 0 °C. This study provides a promising avenue for the application of high‐performance batteries in harsh environment from the perspective of separator engineering. [ABSTRACT FROM AUTHOR]

Lithium-sulfur (Li-S) batteries hold the potential to revolutionize energy storage due to the high theoretical capacity and energy density. However, the commercialization process is seriously hindered by the rapid capacity decay and low utilization of sulfur, caused by the inevitable slow dynamics and the "shuttle effect". The incorporation of metal-based electrocatalysts into sulfur cathodes shows promise in promoting the conversion of lithium polysulfides (LiPSs), reducing the "shuttle effect", and enhancing cell kinetics and cycle life. Among these, Fe-based materials, characterized by environmental friendliness, low cost, abundant reserves, and high activity, are extensively used in sulfur cathode modification. This article reviews the advancements of Fe-based materials in enhancing Li-S batteries in recent years. Starting from single/multi-component Fe-based metal compounds and single/bimetallic atoms, the influence of different Fe coordination environments on the conversion mechanism of LiPSs is analyzed. It is hoped that this review and the proposed prospects can further stimulate the development and application of the Fe element in Li-S batteries in the future. [ABSTRACT FROM AUTHOR]

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Highlights By introducing fluorine modulation into MXene, a new MXene-derived material TiOF/Ti3C2 was successfully synthesized with a distinctive three-dimensional structure and a tailored F distribution. In situ characterizations and electrochemical analyses demonstrate that TiOF/Ti3C2 catalysts effectively coupled the multiphase sulfur species conversion processes. The investigations reveal that the theoretical basis of the fluorine catalysis in Li–S batteries originated from Lewis acid–base mechanisms and charge compensation mechanisms.

Abstract Room‐temperature sodium‐sulfur (RT Na‐S) batteries are a promising next‐generation energy storage device due to their low cost, high energy density (1274 Wh kg−1), and environmental friendliness. However, RT Na‐S batteries face a series of vital challenges from sulfur cathode and sodium anode: (i) sluggish reaction kinetics of S and Na2S/Na2S2; (ii) severe shuttle effect from the dissolved intermediate sodium polysulfides (NaPSs); (iii) huge volume expansion induced by the change from S to Na2S; (iv) continuous growth of sodium metal dendrites, leading to short‐circuiting of the battery; (v) huge volume expansion/contraction of sodium anode upon sodium plating/stripping, causing uncontrollable solid‐state electrolyte interphase growth and “dead sodium” formation. Various strategies have been proposed to address these issues, including physical/chemical adsorption of NaPSs, catalysts to facilitate the rapid conversion of NaPSs, high‐conductive materials to promote ion/electron transfer, good sodiophilic Na anode hetero‐interface homogenized Na ions flux and three‐dimensional porous anode host to buffer the volume expansion of sodium. Heterostructure materials can combine these merits into one material to realize multifunctionality. Herein, the recent development of heterostructure as the host for sulfur cathode and Na anode has been reviewed. First of all, the electrochemical mechanisms of sulfur cathode/sodium anode and principles of heterostructures reinforced Na‐S batteries are described. Then, the application of heterostructures in Na‐S batteries is comprehensively examined. Finally, the current primary avenues of employing heterostructures in Na‐S batteries are summarized. Opinions and prospects are put forward regarding the existing problems in current research, aiming to inspire the design of advanced and improved next‐generation Na‐S batteries.

Lithium–sulfur (Li–S) batteries have attracted significant attention in the realm of electronic energy storage and conversion owing to their remarkable theoretical energy density and cost‐effectiveness. However, Li–S batteries continue to face significant challenges, primarily the severe polysulfides shuttle effect and sluggish sulfur redox kinetics, which are inherent obstacles to their practical application. Metal‐organic frameworks (MOFs), known for their porous structure, high adsorption capacity, structural flexibility, and easy synthesis, have emerged as ideal materials for separator modification. Efficient polysulfides interception/conversion ability and rapid lithium‐ion conduction enabled by MOFs modified layers are demonstrated in Li–S batteries. In this perspective, the objective is to present an overview of recent advancements in utilizing pristine MOF materials as modification layers for separators in Li–S batteries. The mechanisms behind the enhanced electrochemical performance resulting from each design strategy are explained. The viewpoints and crucial challenges requiring resolution are also concluded for pristine MOFs separator in Li–S batteries. Moreover, some promising materials and concepts based on MOFs are proposed to enhance electrochemical performance and investigate polysulfides adsorption/conversion mechanisms. These efforts are expected to contribute to the future advancement of MOFs in advanced Li–S batteries. [ABSTRACT FROM AUTHOR]

Catalysis is crucial to improve redox kinetics in lithium–sulfur (Li–S) batteries. However, conventional catalysts that consist of a single metal element are incapable of accelerating stepwise sulfur redox reactions which involve 16‐electron transfer and multiple Li2Sn (n = 2–8) intermediate species. To enable fast kinetics of Li–S batteries, it is proposed to use high‐entropy alloy (HEA) nanocatalysts, which are demonstrated effective to adsorb lithium polysulfides and accelerate their redox kinetics. The incorporation of multiple elements (Co, Ni, Fe, Pd, and V) within HEAs greatly enhances the catalytically active sites, which not only improves the rate capability, but also elevates the cycling stability of the assembled batteries. Consequently, HEA‐catalyzed Li–S batteries achieve a high capacity up to 1364 mAh g−1 at 0.1 C and experience only a slight capacity fading rate of 0.054% per cycle over 1000 cycles at 2 C, while the assembled pouch cell achieves a high specific capacity of 1192 mAh g−1. The superior performance of Li–S batteries demonstrates the effectiveness of the HEA catalysts with maximized synergistic effect for accelerating S conversion reactions, which opens a way to catalytically improving stepwise electrochemical conversion reactions. [ABSTRACT FROM AUTHOR]

Zinc–iodine (Zn−I2) batteries are gaining popularity due to cost‐effectiveness and ease of manufacturing. However, challenges like polyiodide shuttle effect and Zn dendrite growth hinder their practical application. Here, we report a cation exchange membrane to simultaneously prevent the polyiodide shuttle effect and regulate Zn2+ deposition. Comprised of rigid polymers, this membrane shows superior swelling resistance and ion selectivity compared to commercial Nafion. The resulting Zn−I2 battery exhibits a high Coulombic efficiency of 99.4 % and low self‐discharge rate of 4.47 % after 48 h rest. By directing a uniform Zn2+ flux, the membrane promotes a homogeneous electric field, resulting in a dendrite‐free Zn surface. Moreover, its microporous structure enables pre‐adsorption of additional active materials prior to battery assembly, boosting battery capacity to 287 mAh g−1 at 0.1 A g−1. At 2 A g−1, the battery exhibits a steady running for 10,000 cycles with capacity retention up to 96.1 %, demonstrating high durability of the membrane. The practicality of the membrane is validated via a high‐loading (35 mg cm−2) pouch cell with impressive cycling stability, paving a way for membrane design towards advanced Zn−I2 batteries. [ABSTRACT FROM AUTHOR]

Highlights: By introducing fluorine modulation into MXene, a new MXene-derived material TiOF/Ti3C2 was successfully synthesized with a distinctive three-dimensional structure and a tailored F distribution. In situ characterizations and electrochemical analyses demonstrate that TiOF/Ti3C2 catalysts effectively coupled the multiphase sulfur species conversion processes. The investigations reveal that the theoretical basis of the fluorine catalysis in Li–S batteries originated from Lewis acid–base mechanisms and charge compensation mechanisms. Fluorine owing to its inherently high electronegativity exhibits charge delocalization and ion dissociation capabilities; as a result, there has been an influx of research studies focused on the utilization of fluorides to optimize solid electrolyte interfaces and provide dynamic protection of electrodes to regulate the reaction and function performance of batteries. Nonetheless, the shuttle effect and the sluggish redox reaction kinetics emphasize the potential bottlenecks of lithium–sulfur batteries. Whether fluorine modulation regulate the reaction process of Li–S chemistry? Here, the TiOF/Ti3C2 MXene nanoribbons with a tailored F distribution were constructed via an NH4F fluorinated method. Relying on in situ characterizations and electrochemical analysis, the F activates the catalysis function of Ti metal atoms in the consecutive redox reaction. The positive charge of Ti metal sites is increased due to the formation of O–Ti–F bonds based on the Lewis acid–base mechanism, which contributes to the adsorption of polysulfides, provides more nucleation sites and promotes the cleavage of S–S bonds. This facilitates the deposition of Li2S at lower overpotentials. Additionally, fluorine has the capacity to capture electrons originating from Li2S dissolution due to charge compensation mechanisms. The fluorine modulation strategy holds the promise of guiding the construction of fluorine-based catalysts and facilitating the seamless integration of multiple consecutive heterogeneous catalytic processes. [ABSTRACT FROM AUTHOR]

Zn‐I2 batteries suffer from uncontrollable shuttle effects of polyiodine ions (I3− and I5−) at the cathode/electrolyte interface and side reactions induced by reactive H2O at the anode/electrolyte interface. In this study, a hydrated eutectic electrolyte is designed that synergizes the eutectic network and functional interfacial adsorbed layer to develop high‐performance Zn‐I2 batteries. The eutectic network can restrain active H2O molecules in the electrolyte to inhibit the side reaction at the anode/electrolyte interface and shuttle effect at the cathode/electrolyte interface. Additionally, the functional interfacial adsorbed layer guides the nucleation behavior of Zn2+ to inhibit the growth of dendrites and also separates the zinc anode from direct contact with active H2O molecules and polyiodine ions to inhibit corrosion. Theoretical calculation, in situ Ultraviolet–visible spectroscopy (UV‐vis) and Raman characterizations, and visualization experiments demonstrate that the hydrated eutectic electrolyte effectively inhibits the shuttling effect and improves the reversibility of zinc deposition/stripping behavior. Consequently, the Zn‐I2 battery can maintain a capacity of 133 mAh g−1 after 5000 cycles at 5 C. This highly efficient synergistic strategy offers a practical approach to the development of advanced Zn‐I2 batteries. [ABSTRACT FROM AUTHOR]

Aqueous Zn–I2 batteries have considerable potential owing to their environmental friendliness and high safety. However, the slow iodine conversion kinetics and shuttle effect prevent their practical applicability. In this study, a series of Zn‐MOF‐74 rods with controllable diameters of 40–500 nm are facilely prepared, denoted as P1–P5. A size confinement strategy effect of Zn‐MOF‐74 derived porous carbon as iodine hosts is proposed to suppress the formation of undesirable iodine species, such as I3− and I5−. Moreover, the graphitization degree of porous carbon samples, including P2‐900, P2‐1000, and P2‐1100, play a critical effect on the iodine conversion kinetics. The P2‐1000 sample possesses a high conductive skeleton and abundant mesopores, which improve the adsorption ability toward iodine species. The electrochemical tests and the in situ technology reveal the size confinement strategy effect and the conversion mechanism of iodine. As a result, the I2@P2‐1000 cathode exhibits a superior discharge capacity of 179.9 mA h g−1 at 100 mA g−1 and exceptional long‐term cycle ability after 5000 cycles. Furthermore, the soft batteries and the flexible quasi‐solid‐state batteries are capable of powering devices, promising to exhibit tremendous adaptability and realize flexible electronic devices in various scenarios. [ABSTRACT FROM AUTHOR]

Alkali metal‐sulfur batteries (MSBs) are one of the most promising next‐generation energy storage technologies due to their high energy density and potential for low cost. They are nonetheless constrained by the sluggish conversion of metal polysulfides (MPS) during the charge/discharge process. Herein, a multifunctional separator able to trap the MPS and catalyze their conversion in the three main MSB chemistries, Li‐, Na‐, and K‐MSBs, is demonstrated. More in detail, SnSe nanosheets are introduced as additive into the cathode side of the glass microfiber (GF) separator of the MSB. Taking lithium‐sulfur batteries (LSBs) as an example, it is demonstrated that the GF‐SnSe separator (GF@SnSe) shows strong chemical affinity to lithium polysulfides (LiPS) and superior catalytic activity, inhibiting the transport of LiPSs to the anode and accelerating their conversion. Combining experimental and calculation results, the SnSe additive is shown to decrease the Li2S decomposition energy barrier. Overall, GF@SnSe separators provide significantly improved LSB rate performance and cycling stability with a 0.049% capacity decay per cycle. Besides, the GF@SnSe separator promotes the electrochemical performance of sodium‐sulfur and potassium‐sulfur batteries. Overall, this work presents a significant advancement in the development of multifunctional separators in LSBs as well as the emerging Na‐S and K‐S systems. [ABSTRACT FROM AUTHOR]

Metal phosphides fabricated using metal organic frameworks (MOF) have recently been widely studied in lithium-sulfur (Li–S) battery because of the unique microstructure and electrocatalytic activity. However, the growth of MOF is very rapid and the particle size mainly focuses on micrometer, which severely limits the catalytic effect. Herein, we fabricate nanoscale MOF embedded with carbon nanotube (CNT), owing to the ultra-small CoP (25 nm, denoted as S-CoP) derived from the phosphating of MOF and unique network of CNT, the designed micro-nano structure S-CoP/CNT accelerates the conversion of lithium polysulfides (LiPSs), boosts the precipitation/decomposition processes of lithium sulfide (Li2S) and provides an effective adsorption barrier. Meanwhile, the fabricated S-CoP/CNT separator endows an ultralong dendrite-free Li deposition up to 1714 h. The Li–S battery with S-CoP/CNT modified separator can deliver an initial capacity of 1513.22 mAh g−1 at 0.1 °C, a reversibility capacity of 574.95 mAh g−1 up to 500 cycles at 0.5 °C. The satisfactory performance is also verified at a high sulfur loading of 4.2 mg cm−2 and a favorable initial capacity of 1161.8 mAh g−1 can be maintained. This study provides a facile strategy to fabricate nano metal phosphides derived from MOF for Li–S battery. [ABSTRACT FROM AUTHOR]

Lithium–sulfur (Li–S) batteries have become promising advanced energy storage and conversion devices because of their high theoretical energy density and specific capacity. Nevertheless, the shuttle effect and slow conversion kinetics of soluble lithium polysulfides (LPSs) have a effect on battery performance. Herein, a Zn–Ni–MOF precursor was synthesized and used to prepare nickel–nitrogen–carbon (Ni–N–C) nanomaterials by removing Zn particles via high-temperature annealing and sacrificial template methods. By incorporating these materials into the Li–S battery separator, the LPS can be effectively blocked and trapped, leading to a conspicuous mitigation of the shuttle effect. Simultaneously, the effective active sites distributed on the surface of Ni–N–C materials facilitate rapid LPSs conversion, resulting in a significant enhancement in electrochemical performance. At a current rate of 0.1C, the initial discharge-specific capacity of 1534 mAh g–1 can be obtained. When the charge–discharge rate is increased to 0.5C, the initial discharge-specific capacity can be measured as 1209 mAh g–1 with a capacity decay rate of only 0.06% per cycle after 300 cycles. Notably, under high-S loading conditions (4.5 mg cm–2), the initial specific capacity is 827.1 mAh g–1 and remains at 634.4 mAh g–1 after 162 cycles at 0.1C. These findings highlight the efficacy of utilizing MOF derivatives to modify conventional Li–S battery separators, effectively mitigating the shuttle effect and enhancing the electrochemical performance of Li–S batteries. [ABSTRACT FROM AUTHOR]

Lithium-sulfur batteries have high energy density and are one of the most promising secondary batteries to alleviating energy scarcity, but many aspects limit their practical applications. Among them, the shuttle effect produced when soluble polysulfides pass through the separator is a big reason for the slow progress in commercialization. In this study, N-doped vanadium pentoxide materials (SZV) were designed and synthesized as a functional material for separator. The SZV material provides abundant adsorption sites and catalytic sites and can effectively inhibit the shuttle effect of polysulfides. The first cycle discharge capacity was 982 mAh g−1 at 1 C, and the capacity decay was only 0.056% per cycle after 1400 cycles. The SZV separator battery have an initial capacity of 869 mAh g−1 at 4 C and retain a capacity of 648 mAh g−1 after 200 cycles. Notably, the modified separator batteries can adapt to temperature changes and show excellent cycling performance. The SZV separator battery has a capacity of 700 mAh g−1 at 60 °C and 864 mAh g−1 at 10 °C after 100 cycles at 0.5 C. [ABSTRACT FROM AUTHOR]

Lithium–sulfur batteries (LSBs) are widely regarded as promising next‐generation batteries due to their high theoretical specific capacity and low material cost. However, the practical applications of LSBs are limited by the shuttle effect of lithium polysulfides (LiPSs), electronic insulation of charge and discharge products, and slow LiPSs conversion reaction kinetics. Accordingly, the introduction of catalysts into LSBs is one of the effective strategy to solve the issues of the sluggished LiPS conversion. Because of their nearly 100% atom utilization and high electrocatalytic activity, single‐atom catalysts (SACs) have been widely used as reaction mediators for LSBs' reactions. Excitingly, the SACs with asymmetric coordination structures have exhibited intriguing electronic structures and superior catalytic activities when compared to the traditional M–N4 active sites. In this review, we systematically describe the recent advancements in the installation of asymmetrically coordinated single‐atom structure as reactions catalysts in LSBs, including asymmetrically nitrogen coordinated SACs, heteroatom coordinated SACs, support effective asymmetrically coordinated SACs, and bimetallic coordinated SACs. Particularly noteworthy is the discussion of the catalytic conversion mechanism of LiPSs spanning asymmetrically coordinated SACs. Finally, a perspective on the future developments of asymmetrically coordinated SACs in LSB applications is provided. [ABSTRACT FROM AUTHOR]

Aqueous zinc–iodine (Zn‐I2) battery is one of the most promising candidates for large‐scale energy storage due to its cost‐effectiveness, environmental friendliness, and recyclability. Its practical application is hindered by challenges including polyiodide "shuttle effect" in the cathode and anode corrosion. In this study, a zinc pyrrolidone carboxylate bifunctional additive is introduced to simultaneously tackle the issues of the polyiodide and Zn anode. It is revealed that the pyrrolidone carboxylate anions decrease the polyiodide concentration by preferential coordination between the pyrrolidone carboxylate anions and I2 based on the Lewis acid‐base effect, suppressing the shuttle effect and therefore improving the conversion kinetics for the iodine redox process. Meanwhile, the pyrrolidone carboxylate anions adsorbed on the Zn anode inhibit Zn corrosion and promote non‐dendritic Zn plating, contributing to impressive Coulombic efficiency and long‐term cycling stability. As a result, the Zn‐I2 full battery with the bifunctional zinc pyrrolidone carboxylate additive realizes a high specific capacity of 211 mAh g−1 (≈100% iodine utilization rate), and an ultralong cycling life of >30 000 cycles with 87% capacity retention. These findings highlight the significant potential of zinc pyrrolidone carboxylate as a transformative additive for aqueous Zn‐I2 batteries, marking a critical advancement in the field of energy storage technologies. [ABSTRACT FROM AUTHOR]

Lithium–sulfur batteries (LSBs) have drawn significant attention owing to their high theoretical discharge capacity and energy density. However, the dissolution of long‐chain polysulfides into the electrolyte during the charge and discharge process ("shuttle effect") results in fast capacity fading and inferior electrochemical performance. In this study, Mn2O3 with an ordered mesoporous structure (OM‐Mn2O3) was designed as a cathode host for LSBs via KIT‐6 hard templating, to effectively inhibit the polysulfide shuttle effect. OM‐Mn2O3 offers numerous pores to confine sulfur and tightly anchor the dissolved polysulfides through the combined effects of strong polar–polar interactions, polysulfides, and sulfur chain catenation. The OM‐Mn2O3/S composite electrode delivered a discharge capacity of 561 mA h g−1 after 250 cycles at 0.5 C owing to the excellent performance of OM‐Mn2O3. Furthermore, it retained a discharge capacity of 628 mA h g−1 even at a rate of 2 C, which was significantly higher than that of a pristine sulfur electrode (206 mA h g−1). These findings provide a prospective strategy for designing cathode materials for high‐performance LSBs. [ABSTRACT FROM AUTHOR]

Abstract The “shuttle effect” issue severely hinders the practical application of lithium–sulfur (Li–S) batteries, which is primarily caused by the significant accumulation of lithium polysulfides in the electrolyte. Designing effective catalysts is highly desired for enhancing polysulfide conversion to address the above issue. Here, the one‐step flash‐Joule‐heating route is employed to synthesize a W‐W2C heterostructure on the graphene substrate (W‐W2C/G) as a catalytic interlayer for this purpose. Theoretical calculations reveal that the work function difference between W (5.08 eV) and W2C (6.31 eV) induces an internal electric field at the heterostructure interface, accelerating the movement of electrons and ions, thus promoting the sulfur reduction reaction (SRR) process. The high catalytic activity is also confirmed by the reduced activation energy and suppressed polysulfide shuttling by in situ Raman analyses. With the W‐W2C/G interlayer, the Li–S batteries exhibit an outstanding rate performance (665 mAh g−1 at 5.0 C) and cycle steadily with a low decay rate of 0.06% over 1000 cycles at a high rate of 3.0 C. Moreover, a high areal capacity of 10.9 mAh cm−2 (1381.4 mAh g−1) is obtained with a high area sulfur loading of 7.9 mg cm−2 but a low electrolyte/sulfur ratio of 9.0 µL mg−1.