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Room‐temperature sodium–sulfur (Na–S) batteries are recognized as promising candidates for next‐generation scalable energy storage systems due to their high energy density and cost‐effectiveness. However, several challenges persist, including the shuttle effect of polysulfide and the compatibility of sodium metal with electrolytes. Herein, the study presents a novel type of localized high‐concentration electrolyte (LHCE), utilizing a cost‐effective, low‐density nonfluorinated diluent, toluene, in contrast to the conventional fluorinated diluents. Based on density functional theory calculations and sodium stripping/plating behavior, toluene demonstrates better reduction stability than other aromatic solvents with different substitutions. Also, compared to the 1,2,2‐tetrafluoroethyl‐2,2,3,3‐tetrafluoropropyl‐ether (TTE) diluent, toluene exhibits enhanced compatibility with sodium metal. Furthermore, it modifies the solvation structure by favoring anion‐dominated species, which contributes to the formation of a robust inorganic‐rich solid‐electrolyte interphase (SEI) with better Na‐ion transport. Consequently, Na–S cells featuring sulfurized polyacrylonitrile (SPAN) cathode with the developed LHCE exhibit good cycling stability with high capacity. The work presents a promising strategy for developing low‐cost practical Na–S batteries. [ABSTRACT FROM AUTHOR]

Sodium‐sulfur (Na─S) batteries have drawn considerable research interest owing to their high theoretical energy density and nature abundance. However, the intrinsic sluggish kinetics that has so far been scarcely explored in the conversion reaction of sodium polysulfides (NaPS) hinders its practical application. Herein, the design strategy of heterointerfaced nanoreactor is presented as sulfur reduction reaction (SRR) electrocatalyst for room temperature Na─S batteries. The synergistic incorporation of heterointerface and confined structure design can modulate the electronic structure of transitional metal active site and upshift its d‐band center, leading to enhanced NaPS adsorption and catalytic conversion toward streamlined SRR. Moreover, the spatial confinement of nanoreactor can not only stockpile nanoparticles to avoid their agglomeration and detachment, but also effectively immobilize sulfur species to inhibit shuttle effect and accommodate volume expansion over sodiation. The as‐developed electrocatalyst can achieve high discharge capacity of 1310 mAh g−1, remarkable cycling stability over 2500 cycles, and excellent performance under high sulfur loading and lean electrolyte/sulfur ratio. Ah level pouch cell can also exhibit promising performance for practical application. This strategy affords a synergistic combination of nanoreactor and heterointerface structure engineering toward fast and reliable electrochemistry, paving ways for the practical application of room temperature Na─S batteries. [ABSTRACT FROM AUTHOR]

Low ionic migration and compromised interfacial stability pose challenges for low‐temperature batteries. In this work, we discovered that even with the state‐of‐the‐art localized high‐concentration electrolytes (LHCEs), uncontrolled Na electrodeposition occurs with a huge overpotential of >1.2 V at −20 °C, leading to cell failure within tens of hours. To address this, we introduce a new electrolyte category that incorporates an ionic liquid as a key solvation species. Diverging from traditional LHCEs, the IL‐tailored LHCE facilitates an anion–solvent‐molecules exchange within the solvation sheath between Na+ and organic cations at low temperatures. This behavior reduces solvation cluster size and strengthens Na+–anion coordination, which proves instrumental in enabling fast ionic dynamics in both the bulk liquid and at the interface. Therefore, durable Na electrodeposition and shuttle‐free, 0.5 Ah sodium–sulfur pouch cells are achieved at −20 °C, for the first time, surpassing the limitations of typical LHCEs. This tailoring strategy opens a  new design direction for advanced batteries operating in fast‐charge and wide‐temperature scenarios. [ABSTRACT FROM AUTHOR]

The dissolution/shuttling of sodium polysulfides, coupled with sodium dendrites growth, severely compromises the lifespan and stability of room temperature sodium–sulfur (RT Na–S) batteries. Herein, it proposes employing a functionalized porous ZIF‐based membrane (PZM) to address these two challenges. First, the metal ions embedded within the zeolitic imidazolate framework chemically bind with polysulfide anions, curtailing their detrimental shuttling. Second, the tailored porous structure of the membrane ensures a selective and uniform pathway for sodium ions, significantly reducing non‐uniform deposition and curbing dendritic sodium growth. Third, the intrinsically non‐combustible nature of the ZIF‐based membrane acts as a fortification against thermal outbursts and electrolyte decomposition. Implementing this polysulfide‐resistant, dendrite‐inhibiting and flame‐retardant PZM with a standard S/C cathode leads to the creation of a robust separator with lean electrolyte RT Na–S battery. This configuration may impart a novel perspective for the advancement and enhancement of RT Na–S battery systems. [ABSTRACT FROM AUTHOR]

Room‐temperature sodium‐sulfur (RT Na−S) batteries, noted for their low material costs and high energy density, are emerging as a promising alternative to lithium‐ion batteries (LIBs) in various applications including power grids and standalone renewable energy systems. These batteries are commonly assembled with glass fiber membranes, which face significant challenges like the dissolution of polysulfides, sluggish sulfur conversion kinetics, and the growth of Na dendrites. Here, we develop an amorphous two‐dimensional (2D) iron tin oxide (A‐FeSnOx) nanosheet with hierarchical vacancies, including abundant oxygen vacancies (Ovs) and nano‐sized perforations, that can be assembled into a multifunctional layer overlaying commercial separators for RT Na−S batteries. The Ovs offer strong adsorption and abundant catalytic sites for polysulfides, while the defect concentration is finely tuned to elucidate the polysulfides conversion mechanisms. The nano‐sized perforations aid in regulating Na ions transport, resulting in uniform Na deposition. Moreover, the strategic addition of trace amounts of Ti3C2 (MXene) forms an amorphous/crystalline (A/C) interface that significantly improves the mechanical properties of the separator and suppresses dendrite growth. As a result, the task‐specific layer achieves ultra‐light (~0.1 mg cm−2), ultra‐thin (~200 nm), and ultra‐robust (modulus=4.9 GPa) characteristics. Consequently, the RT Na−S battery maintained a high capacity of 610.3 mAh g−1 and an average Coulombic efficiency of 99.9 % after 400 cycles at 0.5 C. [ABSTRACT FROM AUTHOR]

The practical application of room‐temperature sodium‐sulfur (RT Na–S) batteries is blocked by the notorious shuttle effect of sodium polysulfides (NaPSs) and sluggish refox reaction kinetics. Single‐atom catalysts (SACs) have been widely studied for boosting the energy storage performance of RT Na‐S batteries. Nevertheless, the catalytic centers of SACs reported so far have focused mainly on symmetrical metal–N4 structures, which offer weak bonding affinity toward polar NaPSs, leading to detrimental shuttle effect and sluggish sulfur conversion kinetics. Herein, a novel asymmetrical Mn–N2 structure is implanted into nitrogen‐doped carbon nanofibers (Mn‐N2/CNs) through thermal NH3 etching of a symmetrical Mn–N2O2 structure. The Mn–N2 structure promotes the bonding affinity and catalytic conversion of NaPSs due to the strengthened d‐p orbital‐hybridization between the d orbital of Mn in the Mn–N2 structure and the p orbital of S in NaPSs. Consequently, Mn‐N2/CNs@S achieves a high capacity of 458 mAh g−1 at 3.0 C with a capacity decay of 0.23% over 2300 cycles. This work offers a promising pathway for regulating the coordination number of SACs with strengthened d‐p orbital‐hybridization for high‐performance RT Na–S batteries. [ABSTRACT FROM AUTHOR]

The room‐temperature sodium‐sulfur (RT Na‐S) batteries have been seriously hindered in their practical application due to the sluggish redox kinetics and incomplete conversion of polysulfides. In this study, a structure‐determined Keggin‐type heteropolyvanadotungstate of H5PW10V2O40·30H2O (PW10V2) is engineered and reveal its catalytic mechanism in RT Na‐S system. With the assistance of precise V sites and highly reversible multi‐electron redox properties, PW10V2 as a bidirectional molecular catalyst expedites the complete conversions between polysulfides and the insoluble sodium sulfide, while undergoing the reversible transformation between its reduced and oxidized states. Furthermore, PW10V2 with multicenter active sites can capture polysulfides efficiently. Consequently, the cell with the constructed PW10V2‐based modified separator achieves the perdurable cyclability up to 4000 loops even at 10 C toward an exceptionally low capacity decay rate of 0.012% per cycle, far surpassing those of current state‐of‐the‐art RT Na‐S batteries that employ the functional materials based on separator. This work first demonstrates the underlying electrochemical reaction processes of polyoxometalate‐based functional materials, which guides solving the challenging issues related to sodium polysulfides in RT Na‐S batteries. [ABSTRACT FROM AUTHOR]

Significant resources and diligent research have been dedicated to the investigation and enhancement of energy storage devices utilising hydrogen, lithium, or sodium. Efforts of this nature strive to offer sustainable energy storage solutions that are both dependable and environmentally friendly. This report presents a review a thorough an examination of the aforementioned technologies, with a particular emphasis on cost-effectiveness and State of Charge (SoC) administration. Furthermore, it comprehensively assesses their specific advantages and downsides. Sodium-based systems, such as sodium-sulfur batteries, exhibit remarkable stability and efficiency in sustaining desired charge levels, starting from the control of SoC. Lithium-based alternatives, such as Lithium-ion batteries (LIBs) have gained extensive usage adopted in several industries because to their enhanced energy density and improved SoC accuracy. The complexity associated with SoC is a challenge for hydrogen-based systems, including hydrogen fuel cells, due to their dependence on gas storage and conversion techniques. The assessment places significant emphasis on cost analysis, which evaluates the economic feasibility of each storage method. Sodium-based systems, known for their well-established technology and ample availability of raw materials, frequently present a financially viable option, especially for large-scale grid implementations. The pricing of lithium-based systems, particularly in the domains of portable devices and electric cars, is competitive because to their quick improvements and decreasing costs. Hydrogen-based systems, despite their initial expensive capital expenditure, exhibit potential through continuous advancements and the expansion of production capacity. [ABSTRACT FROM AUTHOR]

Na2S is a key material in sodium‐sulfur batteries and its single‐monolayer film may also be a new 2D material. Herein, the results are first reported by STM, XPS, and DFT simulation that the Na2S single‐monolayer film shows different atomic structures depending on the underlying metals, and these structures can be changed by thermal annealing. All structures are well supported by DFT simulation on corresponding Na2S up, down, and standing models, as well as the NaS in‐plane model. Further, a wide bandgap of Na2S single‐monolayer film is measured, which decreases from Au(111) to Ag(111) and Cu(111) due to the different Na2S interactions with metal substrates. Finally, it is demonstrated that dibenzo 18‐crown‐6‐ether molecules can grow on phase VI of Na2S film at room temperature, as compared with preferred metal surfaces and Na2S phase III structure. [ABSTRACT FROM AUTHOR]

Room‐temperature sodium–sulfur (RT Na/S) batteries have received increasing attention for the next generation of large‐scale energy storage, yet they are hindered by the severe dissolution of polysulfides, sluggish redox kinetic, and incomplete conversion of sodium polysulfides (NaPSs). Herein, the study proposes a dual‐modulating strategy of the electronic structure of electrocatalyst and sulfur to accelerate the conversion of NaPSs. The selenium‐modulated ZnS nanocrystals with electron rearrangement in hierarchical structured spherical carbon (Se‐ZnS/HSC) facilitate Na+ transport and catalyze the conversion between short‐chain sulfur and Na2S. And the in situ introduced Se within S can enhance conductivity and form an S─Se bond, suppressing the "polysulfides shuttle". Accordingly, the S@Se‐ZnS/HSC cathode exhibits a specific capacity of as high as 1302.5 mAh g−1 at 0.1 A g−1 and ultrahigh‐rate capability (676.9 mAh g−1 at 5.0 A g−1). Even at −10 °C, this cathode still delivers a high reversible capacity of 401.2 mAh g−1 at 0.05 A g−1 and 94% of the original capacitance after 50 cycles. This work provides a novel design idea for high‐performance Na/S batteries. [ABSTRACT FROM AUTHOR]

As one of NEDO's international demonstration projects, a large‐capacity hybrid battery storage system which consists of two types of battery cells with different charge‐discharge characteristics was constructed in the state of Lower Saxony in the Federal Republic of Germany. By using the hybrid battery system has a lithium‐ion which has an advantage in short time and high rate, and a sodium‐sulfur battery (NAS) which has an advantage in long time and low rate, the tender participation in the balancing power market in Germany had been executed. The hybrid battery storage system could successfully drive and provided services for primary and secondary control reserves, elimination of power imbalance, and reactive power injection, as well as a combination of these services. [ABSTRACT FROM AUTHOR]

In the pursuit of high energy density batteries beyond lithium, room-temperature (RT) sodium–sulfur (Na-S) batteries are studied, combining sulfur, as a high energy density active cathode material and a sodium anode considered to offer high energy density and very good standard potential. Different liquid electrolyte systems, including three different salts and two different solvents, are investigated in RT Na-S battery cells, on the basis of the solubility of sulfur and sulfides, specific capacity, and cyclability of the cells at different C-rates. Two alternative cathode host materials are explored: A bimodal pore size distribution activated carbon host AC MSC30 and a highly conductive carbon host of hollow particles with porous particle walls. An Na-S cell with a cathode coating with 44 wt% sulfur in the AC MSC30 host and the electrolyte 1M NaFSI in DOL/DME exhibited a specific capacity of 435 mAh/gS but poor cyclability. An Na-S cell with a cathode coating with 44 wt% sulfur in the host of hollow porous particles and the electrolyte 1M NaTFSI in TEGDME exhibited a specific capacity of 688 mAh/gS. [ABSTRACT FROM AUTHOR]

The effective flow of electrons through bulk electrodes is crucial for achieving high-performance batteries, although the poor conductivity of homocyclic sulfur molecules results in high barriers against the passage of electrons through electrode structures. This phenomenon causes incomplete reactions and the formation of metastable products. To enhance the performance of the electrode, it is important to place substitutable electrification units to accelerate the cleavage of sulfur molecules and increase the selectivity of stable products during charging and discharging. Herein, we develop a single-atom-charging strategy to address the electron transport issues in bulk sulfur electrodes. The establishment of the synergistic interaction between the adsorption model and electronic transfer helps us achieve a high level of selectivity towards the desirable short-chain sodium polysulfides during the practical battery test. These finding indicates that the atomic manganese sites have an enhanced ability to capture and donate electrons. Additionally, the charge transfer process facilitates the rearrangement of sodium ions, thereby accelerating the kinetics of the sodium ions through the electrostatic force. These combined effects improve pathway selectivity and conversion to stable products during the redox process, leading to superior electrochemical performance for room temperature sodium-sulfur batteries. Efficient charge transfer in sulfur electrodes is a crucial challenge for sodium-sulfur batteries. Here, the authors developed a machine-learning-assisted approach to quickly identify effective single-atom catalysts that enhance selectivity for short-chain sodium polysulfides, leading to improved battery performance. [ABSTRACT FROM AUTHOR]

Porous carbon materials with high electrical conductivity and superior mechanical strength have been demonstrated to be one of most promising sulfur hosts for room‐temperature sodium–sulfur (RT Na–S) batteries. However, the nonpolar surface of intact graphite lattice displays weak interaction toward the polar polysulfides, thereby resulting in the notorious shuttle effect and poor sulfur conversion kinetics. Herein, pentagon defects are designed into the graphite lattice to break the integrity of π‐conjugation, making the localized electron distribution to simultaneously enhance the polysulfide affinity and accelerate sulfur conversion kinetics. Notably, the as‐synthesized carbon materials as the sulfur host exhibit a high reversible capacity of 1275 mAh g−1 at 0.1 C after 100 cycles and long‐term cycling stability with low‐capacity decay of only 0.035% per cycle at 3 C over 600 cycles. Density functional theory calculations and electrochemical experiments confirm that pentagon defects could efficiently accelerate the chemical interaction between pentagon carbon atoms and polysulfides, and markedly lower the sulfur conversion kinetics in comparison with intact graphene. This research offers a basis for designing intrinsic pentagon defects in carbon materials as efficient catalysts for RT Na–S batteries. [ABSTRACT FROM AUTHOR]

Room temperature sodium-sulfur (Na-S) batteries, known for their high energy density and low cost, are one of the most promising next-generation energy storage systems. However, the polysulfide shuttling and uncontrollable Na dendrite growth as well as safety issues caused by the use of organic liquid electrolytes in Na-S cells, have severely hindered their commercialization. Solid-state electrolytes instead of liquid electrolytes are considered to be the most direct and effective solution to solve the above problems. However, its practical application is still greatly challenged due to the poor interfacial compatibility between the all-solid-state electrolytes and the anode/cathode, ionic conductivity, and the shuttle effect caused by the presence of liquid phase in the quasi-solid-state electrolytes. This paper presents a comprehensive review of solid-state Na-S batteries from the perspective of regulating interfacial compatibility and improving ionic conductivity as well as suppressing polysulfide shuttle. According to different components, solid-state electrolytes were divided into five categories: solid inorganic electrolytes, solid polymer electrolytes, polymer/inorganic solid hybrid electrolytes, gel polymer electrolytes, and liquid–solid inorganic hybrid electrolytes. Finally, the prospect of developing high performance solid-state electrolytes to improve the cycling stability of room temperature Na-S cells is envisaged. [ABSTRACT FROM AUTHOR]

Abstract Room‐temperature sodium–sulfur (RT Na/S) batteries have received increasing attention for the next generation of large‐scale energy storage, yet they are hindered by the severe dissolution of polysulfides, sluggish redox kinetic, and incomplete conversion of sodium polysulfides (NaPSs). Herein, the study proposes a dual‐modulating strategy of the electronic structure of electrocatalyst and sulfur to accelerate the conversion of NaPSs. The selenium‐modulated ZnS nanocrystals with electron rearrangement in hierarchical structured spherical carbon (Se‐ZnS/HSC) facilitate Na+ transport and catalyze the conversion between short‐chain sulfur and Na2S. And the in situ introduced Se within S can enhance conductivity and form an S─Se bond, suppressing the “polysulfides shuttle”. Accordingly, the S@Se‐ZnS/HSC cathode exhibits a specific capacity of as high as 1302.5 mAh g−1 at 0.1 A g−1 and ultrahigh‐rate capability (676.9 mAh g−1 at 5.0 A g−1). Even at −10 °C, this cathode still delivers a high reversible capacity of 401.2 mAh g−1 at 0.05 A g−1 and 94% of the original capacitance after 50 cycles. This work provides a novel design idea for high‐performance Na/S batteries.

Room‐temperature sodium–sulfur (RT Na–S) batteries have emerged as a promising candidate for next‐generation scalable energy storage systems, due to their high theoretical energy density, low cost, and natural abundance. However, the practical applications of these batteries are hindered by the notorious shuttle effect of soluble sodium polysulfides (NaPSs) and sluggish reaction kinetics, which result in fast performance loss. To address this issue, recent studies have reported impressive achievements of transition metal nanoparticles/single atoms/cluster/compounds (TM)‐based host materials with strong adsorption and catalyzation to NaPSs. These materials can significantly improve the electrochemical performance of RT Na–S batteries. In this review, the recent progress on TM‐based host materials for RT Na–S batteries, including iron (Fe)‐, cobalt (Co)‐, nickel (Ni)‐, molybdenum (Mo)‐, titanium (Ti)‐, vanadium (V)‐, manganese (Mn)‐, and other TM‐based materials are summarized. The design, fabrication, and properties of these host materials are comprehensively summarized and systematically analyzed the underlying chemical inhibition and electrocatalysis mechanism between NaPSs and TM‐based catalytic materials. At last, the challenges and prospects for designing efficient TM‐based catalytic materials for high‐performance RT Na–S batteries are discussed. [ABSTRACT FROM AUTHOR]

Room‐temperature sodium‐sulfur (RT Na–S) batteries are regarded as one of promising next‐generation energy storage systems owing to the high theoretical energy density (1274 Wh kg−1) and rich abundance of the raw materials. However, the sluggish redox kinetics and low electrical conductivity of sulfur (S) cathode significantly imped their practical application. Herein, a flexible carbon film implanted with single‐atomic Zn−N2 moiety (Zn‐N2/CF) is constructed as the efficient S host material to effectively improve the redox kinetics and electrical conductivity. The theoretical and experimental results show that, compared to Zn−N4 center, unsaturated Zn−N2 center with asymmetric electron distribution has significant advantages in anchoring and activating sodium polysulfides to accelerate the conversion from S8 to Na2S and reducing the reaction energy barrier of Na2S decomposition. Consequently, Zn‐N2/CF/S can retain a reversible capacity of 838.5 mAh g−1 at 0.1 A g−1 after 100 cycles, which is higher than that of Zn‐N4/CF/S (688.0 mAh g−1). Moreover, Zn‐N2/CF/S also maintains a long‐term cycling performance with a negligible capacity decay rate of 0.006% per cycle over 4000 cycles at 10 A g−1. This work provides an effective strategy to obtain the flexible carbon film implanted with unsaturated single‐atomic structure, thereby ultimately resulting in high‐performance RT Na–S batteries. [ABSTRACT FROM AUTHOR]

A novel nitrogen-vacancy Ta 3 N 5− x electrocatalyst is designed by utilizing "ship in a bottle" strategy to controllably construct nitrogen defects inside nanopores, effectively regulating sulfur redox reactions and achieving superior room-temperature sodium-sulfur batteries. [Display omitted] Resolving low sulfur reaction activity and severe polysulfide dissolution remains challenging in metal-sulfur batteries. Motivated by a theoretical prediction, herein, we strategically propose nitrogen-vacancy tantalum nitride (Ta 3 N 5 − x) impregnated inside the interconnected nanopores of nitrogen-decorated carbon matrix as a new electrocatalyst for regulating sulfur redox reactions in room-temperature sodium-sulfur batteries. Through a pore-constriction mechanism, the nitrogen vacancies are controllably constructed during the nucleation of Ta 3 N 5 − x. The defect manipulation on the local environment enables well-regulated Ta 5d-orbital energy level, not only modulating band structure toward enhanced intrinsic conductivity of Ta-based materials, but also promoting polysulfide stabilization and achieving bifunctional catalytic capability toward completely reversible polysulfide conversion. Moreover, the interconnected continuous Ta 3 N 5 − x -in-pore structure facilitates electron and sodium-ion transport and accommodates volume expansion of sulfur species while suppressing their shuttle behavior. Due to these attributes, the as-developed Ta 3 N 5 − x -based electrode achieves superior rate capability of 730 mAh g−1 at 3.35 A g−1, long-term cycling stability over 2000 cycles, and high areal capacity over 6 mAh cm−2 under high sulfur loading of 6.2 mg cm−2. This work not only presents a new sulfur electrocatalyst candidate for metal-sulfur batteries, but also sheds light on the controllable material design of defect structure in hopes of inspiring new ideas and directions for future research. [ABSTRACT FROM AUTHOR]

The interaction between heteroatom-doped carbon and MoS 2 was deeply analyzed via experiments and theoretical calculations. Compared with N -doped carbon@MoS 2 /S, the N, O-codoped carbon@MoS 2 /S cathode exhibits higher cycle capacity, rate performance, and D N a + . Based on density functional theory (DFT) calculations, the electron transfer from MoS 2 to O-doped carbon was observed owing to the high electronegativity of O, thus increasing the Lewis acidity of MoS 2 and improving its catalytic activity towards NaPSs by weakening the sodium-sulfur bonds, which suggests NOC@MoS 2 is indeed more suitable for RT Na-S batteries. [Display omitted] • Apply the hierarchical MOF-derived flower-like N, O-codoped carbon@MoS 2 composite for RT Na-S batteries for the first time. • The interaction between N, O-codoped carbon, and MoS 2 was analyzed via experiments and theoretical calculations. • Based on electronic structure calculation, the O doping in the carbon matrix can induce the electron transfer from MoS 2 to the carbon substrate, thus enhancing the Lewis acidity of MoS 2 and increasing the reaction kinetics. Room-temperature sodium–sulfur batteries (RT Na-S) are promising energy storage systems with high energy densities and low costs. Nevertheless, drawbacks, including the limited cycle life and sluggish redox kinetics of sodium polysulfides, hinder their implementation. Herein, a heterostructure of MoS 2 nanosheets coated on a metal–organic framework (MOF)-derived N, O-codoped flower-like carbon matrix (NOC) was designed as a sulfur host for advanced RT Na-S batteries. The NOC@MoS 2 hierarchical host provided a sufficient space to guarantee a high sulfur loading and confinement for the volume expansion of sulfur during the charge/discharge process. According to first-principle calculations, the NOC@MoS 2 composite exhibited metallic conductivity because electronic states crossed the Fermi level, which indicates that the introduction of NOC significantly improved the electronic conductivity of MoS 2. Furthermore, electron transfer from MoS 2 to the O-doped carbon sites was observed owing to the strong electronegativity of O, which can effectively increase the Lewis acidity of MoS 2 and weaken the sodium–sulfur bonds in sodium polysulfides after adsorption on the cathode, leading to reductions in the Na 2 S dissociation energy barrier and Gibbs free energy for the rate-limiting step of the sulfur reduction process. Therefore, with the synthetic effects of MoS 2 and N, O-codoped carbon, the obtained cathode exhibited a superior electrochemical performance. [ABSTRACT FROM AUTHOR]

Rechargeable sodium–sulfur/selenium/iodine (Na–S/Se/I2) batteries are regarded as promising candidates for large‐scale energy storage systems, with the advantages of high energy density, low cost, and environmental friendliness. However, the electrochemical performances of Na–S/Se/I2 batteries are still restricted by several inherent issues, including the "shuttle effect" of polysulfides/polyselenides/polyiodides (PSs/PSes/PIs), sluggish kinetics of the conversion reactions at the cathodes, and Na dendrite growth at the anodes. Among these challenges, uncontrolled "shuttle effect" of PSs/PSes/PIs is a major contributing factor for the irreversible loss of active cathode materials and severe side reactions on Na metal anodes, leading to rapid failure of the batteries. Separator modification has been demonstrated to be an effective strategy to suppress the shuttling of PSs/PSes/PIs. Herein, the latest achievement in modifying separators for high‐performance Na–S/Se/I2 batteries is comprehensively reviewed. The reaction mechanisms of each battery system are first discussed. Then, strategies of separator modification based on the different functions for regulating the transportation of PSs/PSes/PIs are summarized, including applying electrostatic repulsive interaction, introducing conductive layers, improving sieving effects, enhancing chemisorption capability, and adding efficient electrocatalysts. Finally, future perspectives on the practical application of modified separators in high‐energy rechargeable batteries are provided. [ABSTRACT FROM AUTHOR]

Room temperature sodium‐sulfur (RT‐Na/S) battery is regarded as a promising next‐generation battery system because of their high theoretical specific capacity, and abundant availability of anodes and cathodes. Nevertheless, the direct use of sodium metal could result in the dendrite growth, causing the safety concerns. Interestingly, employing Na2S as the cathode materials can be paired with Na‐free anode to effectively avoid the problem of dendrite growth. However, the poor electronic conductivity of Na2S and the sluggish kinetic conversion to sodium polysulfides can lead to high initial charge activation barriers and rapid capacity degradation, thereby constraining their practical application. In this concept, the electrochemical mechanism of Na2S cathode is summarized to present the potential for RT‐Na/S batteries. Additionally, recent advances on Na2S cathodes have been discussed in detail with an emphasis on functionalized matrix, morphology modulation, and optimizing cell structure. Finally, the future opportunities and challenges for the development of Na2S cathode based RT‐Na/S batteries are proposed. [ABSTRACT FROM AUTHOR]

In this review, the formation mechanism of NaPSs shuttling and their interaction with different battery components are introduced in detail, and recent advances and strategies for suppressing the shuttle effect of polysulfides are systematically discussed, which will point out the direction to design high-performance RT Na-S batteries. [Display omitted] • Room-temperature sodium-sulfur batteries are emerging as a promising next-generation energy storage system. • The efficient suppression of the shuttle effect is crucial to improve the battery cycling stability. • A comprehensive review targets the underlying mechanisms of shuttling behavior. Room-temperature sodium-sulfur (RT Na-S) batteries are considered as a promising next-generation energy storage system due to their remarkable energy density and natural abundance. However, the severe shuttling behavior of sodium polysulfides (NaPSs) significantly hinders their commercial visibility. Therefore, several strategies have been developed to tackle this issue, which is crucial to boosting the reaction kinetics of sulfur and enhancing the battery cycling stability. This review meticulously and comprehensively summarizes the various strategies employed by different components to inhibit the shuttling of NaPSs. First, we describe the working principles of RT Na-S batteries and the corresponding formation mechanism of the shuttle effect in detail. Subsequently, the latest advancements and techniques for alleviating the NaPSs shuttling are systematically examined from four perspectives: cathode, electrolyte, separator, and anode. Finally, this review presents an exhaustive analysis of the current challenges and future research prospects concerning the inhibition of the shuttle effect in RT Na-S batteries. [ABSTRACT FROM AUTHOR]

Sodium-sulfur (Na−S) batteries are promising energy storage devices for large-scale applications due to their high-energy-density and abundant material reserve. However, the practical implementation of room temperature (RT) Na−S batteries faces challenges, including low-energy-density and limited lifespan, particularly attributed to the properties of sulfurized polyacrylonitrile (SPAN). In this study, we address these challenges by introducing tellurium doping into SPAN nanoflowers, enhancing their performance for Na−S batteries. The resulting material exhibits high sulfur loading as well as superior electron and ion transport properties, leading to enhanced redox kinetics and improved battery performance. The tellurium-doped SPAN nanoflower electrode delivers an exceptional composite capacity of 700 mAh g−1 at 0.1 C and demonstrates stable cycling over 2400 cycles with minimal capacity fade (0.01 % average fading rate). Even under challenging conditions (24.0 mg cm−2, E/S=5 mg μL S −1, N/P=2.1), the Na−S battery achieves a high areal capacity of 16.1 mAh cm−2, resulting in an impressive energy density of 340.9 Wh kg–1 based on cathode and anode. This work presents a promising approach to designing high-energy-density, long-lifespan RT Na−S batteries, with potential applications for other metal-sulfur battery systems. [Display omitted] • The synergy of Te-doping and nanoflower enables SPAN-based cathode with superior kinetics and high capacity. • Sulfur cathode exhibits ultrahigh specific capacities and remarkable long-lifespan in Na−S batteries. • Na-S cell delivers an ultrahigh areal capacity of 16.1 mAh cm−2 and a calculated energy density of 340.9 Wh kg−1 [ABSTRACT FROM AUTHOR]

[Display omitted] • A ZIF-8 enhanced PVDF/PEO blending polymer gel membrane (PPZ) is designed. • The PPZ with the dense framework exhibits the rapid Na+ migration, superior mechanical property, which is conductive to regulate the Na+ ion flux with the uniform Na plating. • The Na/PPZ-GPE/Na cell delivered the stable cycling for 250 h with almost constant voltage hysteresis of 150 mV. • The SPAN/PPZ-GPE/Na cell exhibited the high capacity of 1585.4 mA h g−1 with the capacity retain of 97 % of third cycle after 465 cycles. Ambient-temperature sodium-sulfur (Na-S) battery with high energy density and low cost has been considered as the promising energy density system. However, its commercial application is limited by the rapid capacity decay of the sulfur electrode and the instability of sodium dendrites with the safety issues. Herein, a ZIF-8 enhanced PVDF/PEO blending polymer gel membrane (PPZ) is reported for stable and safe quasi-solid-state Na-S battery with sulfurized polyacrylonitrile (SPAN) cathode and Na metal anode. The optimized gel polymer membrane with the dense framework exhibited the rapid Na+ migration, superior mechanical property with the tensile strength of 16.5 MPa and the elongation-at-break of 171 %, which is conductive to regulate the Na+ ion flux with the uniform Na plating and prevent the dendritic growth. The assembled symmetric Na/PPZ-GPE/Na cell delivered the stable cycling for 250 h with almost constant voltage hysteresis of 150 mV. Benefited from the superior interfacial stability between PPZ-GPE and Na as well as PPZ-GPE and SPAN, the SPAN/PPZ-GPE/Na cell exhibited the high capacity of 1585.4 mA h g−1 with the capacity retain of 97 % of third cycle after 465 cycles. This work offers exemplary electrolyte design that concurrently and effectively tackles the problems in Na-S battery and presents an excellent quasi-solid sodium-sulfur battery with the high capacity and long cycling. [ABSTRACT FROM AUTHOR]

[Display omitted] • A hetero-structured Ni-MnO 2 embedded on the nitrogen-doped hollow carbon sphere was synthesized. • The 3D hollow structure facilitates charge/ion transport and shortens the mass transport distance. • Heterostructured Ni-MnO 2 demonstrates the dual effect of chemisorption and catalytic conversion of polysulfide. • Nitrogen-doped hollow carbon spheres efficiently suppress the polysulfide shuttling and improve the low intrinsic conductivity of active sulfur. The room-temperature sodium-sulfur (RT Na-S) battery is considered to be a highly promising electrochemical energy storage device, attributed to its high energy density, rich sulfur reserve, and nontoxicity. However, it is constrained by the polysulfide shuttling and the low intrinsic conductivity of active sulfur. A sacrificial template method has been used to develop hetero-structured Ni-MnO 2 embedded in micro/mesoporous hollow carbon spheres (HCS@Ni-MnO 2) to overcome these challenges. As evidenced by electrochemical properties and computational results, the construction of hetero-structured Ni-MnO 2 provides a strong affinity to polysulfides. Meanwhile, the highly conductive in-situ constructing Ni-MnO 2 structure has strong adsorption to soluble sodium polysulfides and effectively improves the catalytic conversion. The micro- and mesoporous hollow carbon sphere improves the reactivity of the sulfur cathodes and physically suppresses polysulfides shuttling. Befitting from the physical and chemical confinement and the fast redox reaction of polysulfides, the as-prepared S/HCS@Ni-MnO 2 cathode exhibits a high capacity of 1031.7 mAh g−1 at 0.2 A g−1 after 100 cycles, surpassing the capacities of S/HCS@Ni (820.3 mAh g−1), S/HCS@MnO 2 (942.4 mAh g−1) and S/HCS (866.7 mAh g−1). Moreover, the battery with S/HCS@Ni-MnO 2 cathode also exhibits excellent cycle life (586.8 mAh g−1 at 5 A g−1 after 1000 cycles) and a high rate performance (553.8 mAh g−1 at 10 A g−1). This study provides an efficient strategy for synthesizing multiple compound hetero-structured materials to facilitate the development of energy storage applications. [ABSTRACT FROM AUTHOR]

Room-temperature (RT) sodium-sulfur (Na–S) battery is a promising energy storage technology with low-cost, high-energy-density and environmental-friendliness. However, the current RT Na–S battery suffers from various problems, such as poor cycling stability and poor electrolyte-electrode compatibility caused by polysulfide shuttling and active Na-metal anode. Here, a nonflammable localized high-concentration electrolyte (LHCE) (sodium bis(trifluoromethanesulfonyl)imide salt, sulfolane solvent and 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether diluent in a molar ratio of 1:2:2), and a pre-sodium activated carbon cloth (NaACC) anode, are combined to enable stable and high-safety RT Na–S battery. In LHCE, the shuttle effect of polysulfide is greatly alleviated, a stable anions-derived NaF-rich cathode electrolyte interphase is formed, and a solid-solid conversion mechanism of a solid S 8 -solid Na 2 S n (1 ≤ n ≤ 3) is achieved. Meanwhile, the Na dendrites and side reactions between electrolyte and anode are effectively inhibited by using NaACC anode. Therefore, under the synergistic effect of electrolyte regulation and negative electrode structure optimization, although using a low N/P ratio of 1.7, the RT Na–S battery also delivers a high initial capacity of 1220.8 mAh g−1, good rate capability and stable cycling performance with a high average Coulombic efficiency of 99.1 %. The capacity still remains at 704.5 mAh g−1 after 100 cycles. This innovative combination of LHCE and NaACC anode in Na–S batteries provides a new idea for further achieving stable RT Na–S batteries with long-cycle-life and high-safety. [Display omitted] • Synergy of LHCE and NaACC anodes enables safe and stable RT Na–S batteries. • LHCE realizes the solid S 8 -solid Na 2 S n (1 ≤ n ≤ 3) conversion mechanism. • The NaACC electrode inhibits side effects and the growth of sodium dendrites. • RT Na–S full cells have good cycle performance and high Coulombic efficiency. [ABSTRACT FROM AUTHOR]

A research article titled "Inside Front Cover: Amorphous FeSnOx Nanosheets with Hierarchical Vacancies for Room-Temperature Sodium-Sulfur Batteries" discusses the development of a new type of nanosheet for use in sodium-sulfur batteries. The nanosheet contains oxygen vacancies and nano-sized perforations, which provide strong adsorption and catalytic sites for polysulfides, as well as facilitate the regulation of sodium-ion transport. This new material, when used as a layer overlaying commercial separators, enhances the electrochemical performance of sodium-sulfur batteries. The article highlights the ultra-light, ultra-thin, and ultra-robust properties of this nanosheet. [Extracted from the article]

Metal–Sulfur (Li/Na–S) battery technology is considered one of the most promising energy storage systems because of its high specific capacity of 1675 mA h/g, attributed to sulfur. However, the rapid capacity degradation, mainly caused by metallic polysulfide dissolution, remains a significant challenge prior to practical applications. This work demonstrates for the first time that a Fe-based metal organic framework (MIL-100(Fe)) can remarkably stabilize the electrochemical behavior of sulfur-cathodes in Metal-S cells during prolonged cycling. The chemical and morphological properties of MIL-100(Fe) and, especially conjugated with their textural characteristics, can help immobilize lithium/sodium polysulfides within the highly microporous cathode structure. Capacity loss per cycle is 0.044 mA h after 3000 cycles at 2C in Li–S cells. This behavior is confirmed when the MOF-based cathode is studied in RT Na–S batteries, managing to stabilize the capacity with a loss of less than 0.08 % during 2000 cycles at 0.1 C-rate. The excellent performance can be attributed to the synergistic effects of the highly microporous structure of MOF-100(Fe), which provide an ideal matrix to confine polysulfides, and the presence of Fe(III) active centers that provide chemical affinities to sulfur and polysulfides. These factors contribute to the excellent cycling performance of the S@MIL-100(Fe) composite in Metal-Sulfur batteries. [Display omitted] • For the first time, Fe-based MOF is used as a sulfur-host in metal-sulfur cathodes. • MIL-100(Fe) MOF morphology is maintained during electrode preparation process. • Remarkable rate capability behavior and low polarization are shown by MIL-100(Fe). • Sulfur/MIL-100(Fe) cathodes overperform other MOFs in Li–S reaching 3000 cycles. • Highly stable Na–S cathodes are achieved with sulfur/MIL-100(Fe) composites. [ABSTRACT FROM AUTHOR]

The development of room-temperature sodium sulfur batteries is severely constrained by the sluggish solid-solid conversion kinetics of Na 2 S/Na 2 S 2 and the accumulation of "dead Na 2 S/Na 2 S 2 ". Here, we accelerate the conversion kinetics of Na 2 S/Na 2 S 2 as well as reduce the accumulation of "dead Na 2 S/Na 2 S 2 " by 1-butyl-1-methylpyrrolidine trifluoromethanesulfonate ([P14][OTf]) ionic liquid additive that is compatible with metallic Na and has high Na 2 S/Na 2 S 2 solubility. The results of three-electrode kinetics tests show a significant enhancement of the apparent redox kinetics of Na 2 S/Na 2 S 2 through increasing its concentration. During battery cycling, the increase in Na 2 S/Na 2 S 2 concentration can induce the formation of three-dimensional Na 2 S deposition and reduce the coverage of the electrode effective electroactive area, thus decreasing the battery polarization, especially at high rates. In addition, high Na 2 S/Na 2 S 2 solubility can promote the reuse of "dead Na 2 S/Na 2 S 2 " and greatly improve the utilization of active material. At 2C rate, 351 mAh g−1 can be maintained after 800 cycles, and the capacity decay per cycle is 0.046 %. The rate and cycle performance of the battery are greatly improved. Further, a mechanism is proposed for the enhancement of battery performance via overpotential and diffusion theories. [Display omitted] • The solubility of Na 2 S/Na 2 S 2 is increased to three times with the addition of [P14][OTf] to the electrolyte. • The increase in Na 2 S/Na 2 S 2 concentration induces the formation of three-dimensional Na 2 S deposition. • High Na 2 S/Na 2 S 2 solubility can promote the reuse of "dead Na 2 S/Na 2 S 2 ". • A mechanism of improved battery performances is proposed via overpotential and diffusion theories. [ABSTRACT FROM AUTHOR]

Captured by high theoretical capacity and low-cost, Sodium-Sulfur (Na-S) batteries have been deemed as promising energy-storage systems. However, their electrochemical properties, containing both cycling and rate properties, still suffer from the notorious "shuttle effect" of polysulfide. Herein, through the effective regulation of pore sizes, a series of S/SiO 2 cathode materials are obtained. Benefitting from the abundant pore channels of SiO 2 particles, the sulfur loading is as high as 76.3%. Importantly, a suitable pore size can lead to adequate reaction and rapid diffusion behaviors, resulting in excellent electrochemical performances. Specifically, at 2.0 A g -1 , the initial capacity of the as-optimized sample can be up to 1370.6 mAh g -1 . Surprisingly, even after 1050 cycles, it could achieve a high reversible capacity of 1280.8 mAh g -1 with an attenuation rate of 0.089%. At 5.0 A g -1 , after 500 cycles, the capacity can still remain ≈ 1132.6 mAh g -1 (capacity retention rate, 97.5%). Given this, the work is anticipated to offer an effective strategy for advanced electrodes for Na-S batteries., (© 2024 Wiley‐VCH GmbH.)

• Sulfur-rich polymer cathode for sodium-sulfur batteries was prepared by inverse vulcanization. • The failure mechanism of sulfur-rich polymer cathode at first charge was studied. • Nitrogen-doped carbon is combined with sulfur-rich polymer to reverse the failure. • The composite cathode exhibits unprecedented performance of similar materials. Room temperature sodium-sulfur (RT Na-S) batteries are one of the most promising energy storage systems with high energy density due to the abundant reserves of sodium and sulfur elements on Earth. As a potential cathode material, sulfur-rich polymers are rarely reported in RT Na-S batteries compared with other metal-sulfur batteries. The unusual occurrence is a result of sulfur-rich polymer cathodes failing in Na-S batteries. To reverse the process, herein, we first illuminate the failure mechanism of sulfur-rich polymer cathodes (S-DIB as an example) in Na-S batteries, which root from the chemical reaction between the polysulfide and the sodium anode. To address this issue, we incorporate nitrogen-doped carbon (NC) into composites with S-DIB to establish ion diffusion pathways and limit polysulfide diffusion. The resulting S-DIB@NC composite demonstrates exceptional cycling performance, achieving a high capacity of 457 mA h g-1 after 1300 cycles. This research constitutes a significant step towards enhancing the viability of sulfur-rich polymers in Na-S batteries and paves the way for their widespread application. [Display omitted] [ABSTRACT FROM AUTHOR]

Linearly interlinked single atoms offer unprecedented physiochemical properties, but their synthesis for practical applications still poses significant challenges. Herein, linearly interlinked iron single-atom catalysts that are loaded onto interconnected carbon channels as cathodic sulfur hosts for room-temperature sodium-sulfur batteries are presented. The interlinked iron single-atom exhibits unique metallic iron bonds that facilitate the transfer of electrons to the sulfur cathode, thereby accelerating the reaction kinetics. Additionally, the columnated and interlinked carbon channels ensure rapid Na + diffusion kinetics to support high-rate battery reactions. By combining the iron atomic chains and the topological carbon channels, the resulting sulfur cathodes demonstrate effective high-rate conversion performance while maintaining excellent stability. Remarkably, even after 5000 cycles at a current density of 10 A g -1 , the Na-S battery retains a capacity of 325 mAh g -1 . This work can open a new avenue in the design of catalysts and carbon ionic channels, paving the way to achieve sustainable and high-performance energy devices., (© 2024 The Authors. Advanced Materials published by Wiley‐VCH GmbH.)

• Interaction mechanism of Co 9 S 8 was investigated via the first-principles. • Adsorption energies of Co 9 S 8 towards Na 2 S n are larger than those towards Li 2 S n. • Co 9 S 8 has a more effective suppression on shuttle effect in Na-S than Li-S system. • Co 9 S 8 is a promising cathode material for sulfur in alkali metal-sulfur batteries. Severe shuttle effect will deteriorate electrochemical performances of alkali metal-sulfur batteries involving lithium- or sodium-sulfur batteries. In this paper, the interaction mechanism between Co 9 S 8 and polysulfides (Li 2 S n /Na 2 S n) has been investigated thoroughly via the first-principles calculations. Both band structure and density of state show the metallicity of Co 9 S 8 , implying its positive role in conductivity improvement for cathodes. The adsorption energies of Co 9 S 8 towards long-chain Na 2 S n are larger than those towards Li 2 S n , indicating a more effective suppression of Co 9 S 8 on shuttle effect in Na-S than Li-S system. Co 9 S 8 also exhibits a catalytic property to beneficially decrease the Gibbs free energy barrier and thus speed up electrochemical reactions. Co 9 S 8 has been verified theoretically to be a promising cathode material for alkali metal-sulfur batteries. [ABSTRACT FROM AUTHOR]