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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]

[Display omitted] • MFB additive optimizes the solvation structure of Na+ and the interfacial chemistry of the Na anode. • The lower LUMO value of MFB compared to PC facilitates the formation of a NaF-rich inorganic phase SEI. • F-containing CEIs are formed at the sulfur-based cathode, which greatly improves the performance of RT Na-S batteries. Room temperature sodium-sulfur (RT Na-S) batteries are considered as advanced energy storage technology due to their low cost and high theoretical energy density. However, challenges such as the growth of sodium dendrite and dissolution of sodium polysulfides significantly hinder the electrochemical performance. Herein, we developed a propylene carbonate (PC)-based electrolyte with Methyl 2-Fluoroisobutyrate (MFB) as an additive. The ester group in the MFB additive is capable of participating in and reconfiguring the coordination of their Na+ solvated structures, thereby lowering the desolvation barrier and regulating the Na anode's interfacial reaction and nucleation behavior. The polar C−F bond at the other end helps to reduce the lowest unoccupied molecular orbital (LUMO) energy of the MFB additive, enabling the preferential decomposition of MFB to form the F-rich inorganic phase strong polar solid electrolyte interphase (SEI), contributing to the inhibition of Na dendrite growth, the accumulation of dead Na. In addition, NaF-riched cathode electrolyte interphase (CEI) was also observed on sulfur-based cathode, which can effectively inhibited the shuttle effect. Consequently, the developed RT Na-S battery exhibit excellent electrochemical performance. [ABSTRACT FROM AUTHOR]

[Display omitted] Room temperature sodium-sulfur (RT-Na/S) batteries are a promising candidate for large-scale energy storage systems owing to their low manufacturing cost and high energy density. However, the severe shuttle effects and sluggish reaction kinetics hinder their practical application. Here, a Fe 3 Se 4 nanoparticle anchored three-dimensional nitrogen-doped porous carbon nanosheet was designed as a functional defender to inhibit the shuttle effect and achieve high sulfur utilization. The porous carbon nanosheet builds a fast platform for electron and ion transport and acts as a limiting barrier for polysulfide dissolution and shuttling. Additionally, Fe 3 Se 4 nanoparticles are incorporated to enhance the chemical anchoring and catalytic activity of polysulfides. The ex-situ characterization revealed that the Fe sites can feed electrons to polysulfides, thus facilitating the conversion of long-chain polysulfides to Na 2 S, resulting in high sulfur availability (323 mAh/g at 2 A/g) and long-term cycle life (72 % capacity retention at 1 A/g for 500 cycles). [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]

In this study, we monitor the dissolution of sulfur and sulfides in electrolyte solvents for lithium–sulfur (Li–S) and sodium–sulfur (Na–S) batteries. The first aim of this research is to assemble a comprehensive set of data on solubilities and dissolution kinetics that may be used in the simulation of battery cycling. The investigation also offers important insights to address key bottlenecks in the development and commercialization of metal–sulfur batteries, including the incomplete dissolution of sulfur in discharge and insoluble low-order sulfides in charge, the probability of shuttling of soluble polysulfides, and the pausing of the redox reactions in precipitated low order sulfides depending on their degree of solid state. The tested materials include sulfur, lithium sulfides Li2Sx, x = 1, 2, 4, 6, and 8, and sodium sulfides Na2Sx, x = 1, 2, 3, 4, 6, and 8, dissolved in two alternative electrolyte solvents: DOL:DME 1:1 v/v and TEGDME. The determined properties of the solute dissolution in the solvent include saturation concentration, mass transfer coefficient, and diffusion coefficient of the solvent in the solid solute. In general, the DOL:DME system offers high solubility in Li–S batteries and TEGDME offers the highest solubility in Na–S batteries. Low solubility sulfides are Li2S2 and Li2S for the Li–S batteries, and Na2S3, Na2S2, and Na2S for the Na–S batteries. However, it is noted that Na2S3 dissolves fast in TEGDME and also TEGDME diffuses fast into Na2S3, offering the possibility of a swollen Na2S3 structure in which Na+ ions might diffuse and continue the redox reactions in a semisolid state. [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]

Room‐temperature sodium–sulfur batteries are potential candidate for sustainable large‐scale energy storage systems due to their high energy density and low cost. However, the shuttling effect of high‐order polysulfides (Na2Sn, 4 < n ≤ 8) usually leads to rapid capacity fading, while the reaction kinetics of low‐order polysulfides (Na2Sn, 1 ≤ n ≤ 4) are slow. In this work, microporous‐mesoporous carbon derived from mangosteen peels is reported as cathode materials for RT Na–S batteries. The designed micro‐mesoporous structure not only effectively suppresses the shuttling effect of sodium polysulfides (NaPS), but also has high electrical conductivity and porosity, which facilitates electron/ion diffusion. Oxygen functional groups on the surface provide high catalytic activity for efficient low‐order NaPS conversion. The obtained Na–S battery exhibits high reversible capacity with excellent long‐term cycle performance (526.1 mAh g−1 at 4 A g−1 after 1000 cycles) and outstanding rate performance (676.59 mAh g−1 at 16 A g−1). This work demonstrates a novel activation strategy of biomass‐derived carbons for high‐performance Na–S batteries. [ABSTRACT FROM AUTHOR]

The electrochemical performance of room-temperature sodium-sulfur batteries (SSBs) is limited by slow reaction kinetics and sulfur loss in the form of sodium polysulfides (SPSs). Here, it is demonstrated that through electron spin polarization, at no additional energy cost, an external magnetic field (M on) generated by a permanent magnet can significantly improve the SPSs adsorption capacity and reaction dynamics of a ferrimagnetic sulfur host. More specifically, the preparation of a carbon nanofiber/CoFe2O4/S (CNF/CoFe2O4/S) cathode with unprecedented performance and stability at ambient temperature is detailed when M on. It is experimentally and theoretically demonstrated that the magnetic field polarizes the electrons of Co ions, enhancing the adsorption of SPSs and their catalytic conversion. CNF/CoFe2O4/S cathodes with spin polarization provide unprecedented decay rates down to 0.0039% per cycle at 1.0 C for 2700 cycles. The performance of SSBs is further tested, which has 248 mAh g-1 under 1.0 C after 100 cycles when M on. Furthermore, it is evidenced that even when removing the external magnetic field, the magnetic polarization effect persists, opening the door for practical applications. This study not only demonstrates an effective strategy to improve electrochemical performance in SSBs, but also contributes to the enrichments of spin effects in the fields of electrocatalysis. [ABSTRACT FROM AUTHOR]

Room-temperature sodium–sulfur batteries are still hampered by severe shuttle effects and sluggish kinetics. Most of the sulfur hosts require high cost and complex synthesis process. Herein, a facile method is proposed to prepare a phosphorous doped porous carbon (CSBP) with abundant defect sites from camellia shell by oxidation pretreatment combined with H3PO4 activation. The pretreatment can introduce pores and adjust the structure of biochar precursor, which facilitates the further activation of H3PO4 and effectively avoids the occurrence of large agglomeration. Profiting from the synergistic effects of physical confinement and doping effect, the prepared CSBP/S cathode delivers a high reversible capacity of 804 mAh g−1 after 100 cycles at 0.1 C and still maintains an outstanding capacity of 458 mAh g−1 after 500 cycles at 0.5 C (1 C = 1675 mA g−1). This work provides new insights into the rational design of the microstructures of carbon hosts for high-performance room temperature sodium–sulfur batteries. [ABSTRACT FROM AUTHOR]

Complex metal nanoparticles distributed uniformly on supports demonstrate distinctive physicochemical properties and thus attract a wide attention for applications. The commonly used wet chemistry methods display limitations to achieve the nanoparticle structure design and uniform dispersion simultaneously. Solid-phase synthesis serves as an interesting strategy which can achieve the fabrication of complex metal nanoparticles on supports. Herein, the solid-phase synthesis strategy is developed to precisely synthesize uniformly distributed CoFe@FeOx core@shell nanoparticles. Fe atoms are preferentially exsolved from CoFe alloy bulk to the surface and then be carburized into a FexC shell under thermal syngas atmosphere, subsequently the formed FexC shell is passivated by air, obtaining CoFe@FeOx with a CoFe alloy core and a FeOx shell. This strategy is universal for the synthesis of MFe@FeOx (M = Co, Ni, Mn). The CoFe@FeOx exhibits bifunctional effect on regulating polysulfides as the separator coating layer for Li-S and Na-S batteries. This method could be developed into solid-phase synthetic systems to construct well distributed complex metal nanoparticles. Solid-phase synthesis strategy is promising for fabricating desired complex metal nanoparticles on supports. Here, the authors synthesize CoFe@FeOx core-shell nanoparticles as the separator coatings via precise solid-phase method which effectively regulates polysulfides for lithium/ sodium-sulfur batteries. [ABSTRACT FROM AUTHOR]

Recent developments have increased the availability and prevalence of renewable energy sources (RESs) in grid-connected microgrids (MGs). As a result, the operation of an MG with numerous RESs has received considerable attention during the past few years. However, the variability and unpredictability of RESs have a substantial adverse effect on the accuracy of MG energy management. In order to obtain accurate outcomes, the analysis of the MG operation must consider the uncertainty parameters of RESs, market pricing, and electrical loads. As a result, our study has focused on load demand variations, intermittent RESs, and market price volatility. In this regard, energy storage is the most crucial facility to strengthen the MG's reliability, especially in light of the rising generation of RESs. This work provides a two-stage optimization method for creating grid-connected MG operations. The optimal size and location of the energy storage are first provided to support the hosting capacity (HC) and the self-consumption rate (SCR) of the RESs. Second, an optimal constrained operating strategy for the grid-connected MG is proposed to minimize the MG operating cost while taking into account the optimal size and location of the energy storage that was formerly determined. The charge–discharge balance is the primary criterion in determining the most effective operating plan, which also considers the RES and MG limitations on operation. The well-known Harris hawks optimizer (HHO) is used to solve the optimization problem. The results showed that the proper positioning of the battery energy storage enhances the MG's performance, supports the RESs' SCR (reached 100% throughout the day), and increases the HC of RESs (rising from 8.863 MW to 10.213 MW). Additionally, when a battery energy storage system is connected to the MG, the operating costs are significantly reduced, with a savings percentage rate of 23.8%. [ABSTRACT FROM AUTHOR]

Room-temperature sodium–sulfur (Na–S) batteries hold great potential for next-generation energy storage devices due to their high theoretical energy density and low cost. However, the shuttling effect of sodium polysulfide (Na2Sn) species and the sluggish kinetics of the electrochemical conversion reaction greatly hamper the practical application of Na–S batteries. To address these challenges, by means of density functional theory (DFT) computations, we proposed two-dimensional metal chloride (MCl2, M = Mg and Ni) monolayers as multifunctional anchoring materials, including immobilizing soluble Na2Sn intermediates, boosting the reduction reaction of Na2Sn and the decomposition of Na2S species. Our results revealed that the NiCl2 monolayer can effectively immobilize the higher-order Na2Sn species with a stronger binding strength than the common electrolytes to prevent their dissolution. In particular, the NiCl2 substrate exhibits excellent electrocatalytic activity for the sulfur reduction reaction with a low free energy barrier (0.37 eV) and the Na2S decomposition reaction with a small kinetic barrier (0.45 eV), greatly lowering the energy barriers of Na2Sn conversions during discharge and charge and thus guaranteeing the fast redox kinetics and high sulfur utilization of Na–S batteries. Therefore, we predicted that NiCl2 monolayers can be utilized as a highly efficient multifunctional anchoring material for Na–S batteries. [ABSTRACT FROM AUTHOR]

A systematic comparison has been made of three different porous carbon structures derived from waste coffee grounds to investigate the effect of carbon porosity on the electrochemical performance of RT Na–S batteries. The differences in their electrochemical performances were investigated in relation to the pore size distribution and the presence of sulfur molecules (S n , 2 ≤ n ≤ 8) in the pores. We demonstrated that the hierarchically porous structure resulted in good rate capability and superior cycling stability. In particular, optimized carbon with micro-, meso-, and macroporous structures is beneficial because of its excellent wettability and kinetic accessibility. The optimized carbon structure with an appropriate sulfur content exhibited significantly higher capacity retention and long cycle stability in RT Na–S batteries. In addition, the reaction mechanisms have been investigated in combination with X-ray photoelectron spectroscopy measurements during the discharge process. The study established a relevance between the exact regulation of the pore structure of the carbon materials and their electrochemical performance, and also built a correlation between waste biomass and high-effective energy storage materials, which can inspire the rational design of porous carbon structures for further development of the highly efficient, cost-effective and sustainable RT Na–S batteries. The electrochemical performances of RT Na–S batteries were studied by systematically comparing three different porous carbon structures derived from waste coffee grounds, and the reaction mechanisms were investigated by the existing forms of sulfur molecules in the pores, demonstrating the optimized porous carbon structure can lead to a significantly higher capacity retention and long-term cycling stability. [Display omitted] [ABSTRACT FROM AUTHOR]

Room temperature sodium sulfur (RT Na‐S) batteries with high theoretical energy density and low cost have recently gained extensive attention for potential large‐scale energy storage applications. However, the shuttle effect of sodium polysulfides is still the main challenge that leads to poor cycling stability, which hinders the practical application of RT Na‐S batteries. Herein, a multifunctional hybrid MXene interlayer is designed to stabilize the cycling performance of RT Na‐S batteries. The hybrid MXene interlayer comprises a large‐sized Ti3C2Tx nanosheets inner layer followed by a small‐sized Mo2Ti2C3Tx nanoflake outer layer on the surface of the glass fiber (GF) separator. The large‐sized Ti3C2Tx nanosheet inner layer provides an effective physical block and chemical confinement for the soluble polysulfides. The small‐sized Mo2Ti2C3Tx outer layer offers an excellent polysulfide trapping capability and accelerates the reaction kinetics of polysulfide conversion, due to its superior electronic conductivity, large specific surface area, and Mo‐rich catalytic surfaces. As a result, RT Na‐S batteries with this hybrid MXene interlayer modified glass fiber separator deliver a stable cycling performance over 200 cycles at 1 C with an enhanced capacity retention of 71%. This unique structure design provides a novel strategy to develop 2D material‐based functional interlayer for high‐performance metal‐sulfur batteries. [ABSTRACT FROM AUTHOR]

Developing highly efficient catalysts for the Na2S redox process and sodium polysulfide anchoring is becoming increasingly important for high‐performance sodium–sulfur (Na–S) batteries. The recently emerged graphene‐supported biatom catalysts (G‐BACs) exhibit great potential for providing high activity in both discharging and charging processes. However, the fast screening of promising G‐BACs for Na–S batteries is hindered by the formidable computational cost for calculating Na2S decomposition barriers (Eb). Herein, this work develops an "elemental property—adsorption energy descriptor—decomposition barrier" three‐tier model to accelerate this process and elucidates the origin of catalytic activity. It is found that Eb during the charging process is linearly correlated with the adsorption energy difference between the initial and final states of Na2S decomposition (Ediff) for both homonuclear and heteronuclear transition metal G‐BACs. This work further correlates Ediff with intrinsic properties of metal elements by machine learning approaches and unravels the most significant elemental feature to be the outer electron number. This work not only accelerates the design of highly efficient G‐BACs in Na–S batteries based on the structure–activity relationship, but also provides a feasible strategy for the fast screening of catalysts for other electrochemical reactions for potential experimental design. [ABSTRACT FROM AUTHOR]

Room temperature sodium–sulfur (Na–S) batteries are severely hampered by dissolution of polysulfides into electrolytes. Herein, a facile approach is used to tune a biomass‐derived carbon down to an ultrasmall 0.37 nm microporous structure for the first time as a cathode in sodium–sulfur batteries. This produced an intact uniform Na2S membrane to greatly confine the dissolution of polysulfides while realizing a direct solid phase conversion for complete reduction of sulfur to Na2S, which delivers a sulfur loading of 1 mg cm−2 (50 wt.%), an excellent rate capacity (933 mAh g−1 @ 0.1 A g−1 and 410 mAh g−1 @ 2 A g−1), long cycle performance (0.036% per cycle decay at 1 A g−1 after 1500 cycles), and a high energy density for 373 Wh kg−1 (0.1 A g−1) based on whole electrode weight (active sulfur loading + carbon), ranking the best among all reported plain carbon cathode‐based room temperature sodium–sulfur batteries in terms of the cycle life and rate capacity. It is proposed that the solid Na2S produced in the ultrasmall pores (0.37 nm) can be squeezed out to grow an intact membrane on the electrode surface covering the outlet of the pores and greatly depressing the dissolution effect of polysulfides for the long cycle life. This work provides a green chemistry to recycle wastes for sustainable energies and sheds light on design of a unique pore structure to effectively block the dissolution of polysulfides for high‐performance sodium–sulfur batteries. [ABSTRACT FROM AUTHOR]

Sodium‐sulfur (Na–S) batteries that utilize earth‐abundant materials of Na and S have been one of the hottest topics in battery research. The low cost and high energy density make them promising candidates for next‐generation storage technologies as required in the grid and renewable energy. In recent years, extensive efforts have been devoted to the diversity and functionalities of Na–S batteries, aiming to extend their potential applications across multiple temporal and spatial dimensions. Here, we summarize the unconventional designs for the functionalities of Na–S batteries such as flexible batteries, solid‐state cells, flame resistance, and operation at extreme temperatures. By highlighting these design strategies that help to realize the functionalities, we hope this review offers a pathway to foster the bright future of Na–S batteries in diverse applications. [ABSTRACT FROM AUTHOR]

Sodium-sulfur (Na-S) batteries hold great promise for cutting-edge fields due to their high specific capacity, high energy density and high efficiency of charge and discharge. However, Na-S batteries operating at different temperatures possess a particular reaction mechanism; scrutinizing the optimized working conditions toward enhanced intrinsic activity is highly desirable while facing daunting challenges. This review will conduct a dialectical comparative analysis of Na-S batteries. Due to its performance, there are challenges in the aspects of expenditure, potential safety hazards, environmental issues, service life and shuttle effect; thus, we seek solutions in the electrolyte system, catalysts, anode and cathode materials at intermediate and low temperatures (T < 300 °C) as well as high temperatures (300 °C < T < 350 °C). Nevertheless, we also analyze the latest research progress of these two situations in connection with the concept of sustainable development. Finally, the development prospects of this field are summarized and discussed to look forward to the future of Na-S batteries. [ABSTRACT FROM AUTHOR]

Due to the high theoretical energy density, low cost, and rich abundance of sodium and sulfur, room‐temperature sodium–sulfur (RT Na–S) batteries are investigated as the promising energy storage system. However, the inherent insulation of the S8, the dissolution and shuttle of the intermediate sodium polysulfides (NaPSs), and especially the sluggish conversion kinetics, restrict the commercial application of the RT Na–S batteries. To address these issues, various catalysts are developed to immobilize the soluble NaPSs and accelerate the conversion kinetics. Among them, the polar catalysts display impressive performance. Polar catalysts not only can significantly accelerate (or alter) the redox process, but also can adsorb polar NaPSs through polar–polar interaction because of their intrinsic polarity, thus inhibiting the notorious shuttle effect. Herein, the recent advances in the electrocatalytic effect of polar catalysts on the manipulation of S speciation pathways in RT Na–S batteries are reviewed. Furthermore, challenges and research directions to realize rapid and reversible sulfur conversion are put forward to promote the practical application of RT Na–S batteries. [ABSTRACT FROM AUTHOR]

Although batteries fitted with sodium metal anodes and sulfur cathodes are attractive for their higher energy density and lower cost, the threat of polysulfide migration in organic liquid electrolytes, uncontrollable dendrites, and corresponding safety issues has locked the deployment of the battery system. Introduction of solid‐state electrolytes to replace conventional liquid‐based electrolytes has been considered an effective approach to address these issues and further render solid‐state sodium‐sulfur battery (SSSSB) systems with higher safety and improved energy density. Nevertheless, the practical applications of SSSSB are still hampered by grand challenges, such as poor interfacial contact, sluggish redox kinetics of sulfur conversion, and Na dendrites. Currently, various strategies have been proposed and utilized to negate the problems within the solid‐state battery. Herein, a timely and comprehensive review of emerging strategies to promote the development of SSSSB is presented. The critical challenges that prevent the real application of the SSSSB technique are analyzed initially. Subsequently, various strategies for boosting the development of SSSSB are comprehensively summarized, containing the developing of the advanced cathode and cathode/electrolyte interface, tailoring the solid electrolyte, and designing the stable anode and anode/electrolyte interface. Finally, further perspectives on stimulating the practical application of SSSSB technology are provided. [ABSTRACT FROM AUTHOR]

Room-temperature sodium-sulfur batteries (RT-NaSBs) with high theoretical energy density and low cost are ideal candidates for next-generation stationary and large-scale energy storage. However, the dissolution of sodium polysulfide (NaPS) intermediates and their migration to the anode side give rise to the shuttle phenomenon that impedes the reaction kinetics leading to rapid capacity decay, poor coulombic efficiency, and severe loss of active material. Inhibiting the generation of long-chain NaPS or facilitating their adsorption via physical and chemical polysulfide trapping mechanisms is vital to enhancing the electrochemical performance of RT-NaSBs. This review provides a brief account of the polysulfide inhibition strategies employed in RT-NaSBs via physical and chemical adsorption processes via the electrode and interfacial engineering. Specifically, the sulfur immobilization and polysulfide trapping achieved by electrode engineering strategies and the interfacial engineering of the separator, functional interlayer, and electrolytes are discussed in detail in light of recent advances in RT-NaSBs. Additionally, the benefits of engineering the highly reactive Na anode interface in improving the stability of RT-NaSBs are also elucidated. Lastly, the future perspectives on designing high-performance RT-NaSBs for practical applications are briefly outlined. [ABSTRACT FROM AUTHOR]

Room‐temperature sodium–sulfur (RT/Na–S) batteries are a promising low‐cost energy storage technology. However, the vital role of the separator in the system is often overlooked. Inspired by the maintenance of brain homeostasis by human brain capillaries, this work pioneers a host–guest self‐assembled strategy for covalent organic scaffold membranes, endowing the membrane with multiple functions (sodium ion transport, confinement, and conversion of polysulfides) to maintain the stability of the RT/Na–S battery system. The free‐standing multifunctional covalent organic framework membrane (HB/CNT@COF) maximizes the roles of the host framework and guest molecules. Because of the synergistic effect of hydroxynaphthol blue (HB) and multiwalled carbon nanotubes (CNT), the HB/CNT@COF cell exhibits a capacity of 733.4 mAh g−1 with limited capacity fading after 400 cycles at 4 C. This performance is nearly four times that of commercial glass fiber separators. Additionally, the cell demonstrates excellent performance under electrolyte‐poor conditions. [ABSTRACT FROM AUTHOR]

The cathode materials for sodium‐sulfur batteries have attracted great attention since cathode is one of the important components of the sodium‐sulfur battery, and there are cathode materials that have high capacity, non‐toxicity, and cost‐efficiency. Nevertheless, due to their low Coulombic efficiency and proneness to cycling decay, the practical application of the sodium–sulfur battery has always been suppressed. In terms of the responsibility of these problems, the polysulfide shuttle and the sluggish kinetics are the main culprits. To address these issues, impeding the notorious reaction between polysulfide intermediates on the cathode and improve the kinetics reaction on the anode are extremely important. Herein, a comprehensive review is prepared of different approaches to increasing the electrochemical performance and strengthening the stability of cathodes. The influences of various choices and the consequent properties of the cathode in relation to the whole sodium–sulfur battery performance is investigated. Finally, the current research challenges related to cathodes for sodium–sulfur batteries and future perspectives are also discussed. [ABSTRACT FROM AUTHOR]

Room-temperature sodium–sulfur batteries (RT-Na/S batteries) with high reversible capacity (1675 mA h g−1) and excellent energy density (1274 W h kg−1) based on abundant resources of the metal Na have become a research hotspot recently. However, the intermediate product sodium polysulfides (NaPSs) generated during the charge–discharge process are easily dissolved in the ether electrolyte and transferred from the sulfur cathode to the metallic sodium surface, resulting in rapid capacity decay (shuttle effect), which seriously affects the practical application of RT-Na/S batteries. Herein, the mechanism and recent research progress in suppressing the shuttle effect of the sulfur cathode in RT-Na/S batteries are summarized. Strategies such as carbon-based materials physically fixing NaPSs, polar materials absorbing NaPSs to reduce their dissolution, and catalytic materials accelerating the transformation of NaPSs into final products are provided. Challenges and insights into high-performance sulfur electrodes for optimizing RT-Na/S batteries are discussed. [ABSTRACT FROM AUTHOR]

In this paper, a monolayer of TiX2 (X = S, Se) is used to suppress the shuttle effect of polysulfides, thereby accelerating the kinetic process of lower‐order polysulfides. The results show that the adsorption energies of the studied TiX2 for Na2Sn are all better than those of common electrolytes, and the effect of adsorption on the structure of Na2Sn is negligible. The calculated results show that the anchoring behavior of TiX2 to Na2Sn has no effect on the metallic properties of pristine TiX2. On the other hand, the introduction of this material can reduce the diffusion barrier energy of Na2S and improve the utilization rate of sulfur more effectively. In conclusion, TiX2 has suitable adsorption strength, enhances electrical conductivity, and promotes the oxidative decomposition process of polysulfides. It can be theoretically demonstrated that TiS2 is better than TiSe2 in improving the performance of sodium–sulfur batteries and is more suitable as an anchoring material (AM) for sodium–sulfur batteries. [ABSTRACT FROM AUTHOR]

The fundamental challenges that coexisted around sulfur cathode energy storage systems, are the severe polysulfide dissolution and low reactivity resulting in poor reversibility and short cycle life, specifically, in inexpensive sodium ion batteries. Herein, the solution‐processed synthesis of ultra‐high intimate contacted FeS2/S architecture is reported and evolution of the dynamic multistage coupling between the FeS2 and S in sodium–sulfur batteries is revealed. Atomic visualization and in situ spectroscopy conclude that: NaxFeS2 (0

An amorphous GeO x /NC composite as an efficient host for room-temperature sodium–sulfur batteries. The fabricated S@GeO x /NC electrodes with enriched oxygen vacancies to immobilize and facilitate the redox kinetics of polysulfide for RT Na–S batteries, delivering superior electrochemical performance. [Display omitted] The practical applications of room-temperature sodium-sulfur (RT Na-S) batteries have been greatly hindered by the natural sluggish reaction kinetics of sulfur and the shuttle effect of sodium polysulfide (NaPSs). Herein, oxygen vacancy (OV)-mediated amorphous GeO x /nitrogen doped carbon (donated as GeO x /NC) composites were well designed as sulfur hosts for RT Na–S batteries. Experimental and density functional theory studies show that the introduction of oxygen vacancies on GeO x /NC can effectively immobilize polysulfides and accelerate the redox kinetics of polysulfides. Meanwhile, the micro-and mesoporous framework, acting as a reactor for storing active S, is conducive to alleviating the expansion of S during the charging/discharging process. Consequently, the S@GeO x /NC cathode affords a reversible capacity of 1017 mA h g−1 at 0.1 A g−1 after 100 cycles, outstanding rate capability of 333 mA h g−1 at 10.0 A g−1 and long lifespan cyclability of 385 mAh g−1 at 1 A g−1 after 1200 cycles. This work furnishes a new way for the rational design of metal oxides with oxygen vacancies and boosts the application for RT Na-S batteries. [ABSTRACT FROM AUTHOR]

Sodium-sulfur (Na–S) batteries are regarded as one of the promising next-generation energy storage systems; while being more cost-effective than lithium-sulfur batteries, Na–S batteries also suffer from the shuttle effect. Different strategies to tackle the long-chain polysulfide product shuttling issue have been proposed, mainly focusing on sulfur product confinement with costly materials and complex methods. Seeking high-performance and low-cost electrode material precursors is of great importance to promoting Na–S battery applications. We present a high specific surface area microporous carbon framework synthesized from degradable biowaste, namely lychee seeds, with a facile room-temperature etching process. Unlike the traditional dissolution-precipitation mechanism, a quasi-solid-state route takes place with the help of micropore (0.48 nm) confinement, preventing the formation of long-chain polysulfides for excellent electrochemical performance. The obtained Na–S battery exhibits an outstanding initial reversible discharge specific capacity of 1395 mAh g−1 at 0.2C and still maintains a high capacity of 518 mAh g−1 after 500 cycles at 1.0C. The lychee seed-derived microporous carbon provides insights into sustainable and scalable host fabrication for high-performance sulfur-based batteries. [Display omitted] [ABSTRACT FROM AUTHOR]

Room‐temperature sodium–sulfur (RT/Na–S) batteries are regarded as promising large‐scale stationary energy storage systems owing to their high energy density and low cost as well as the earth‐abundant reserves of sodium and sulfur. However, the diffusion of polysulfides and sluggish kinetics of conversion reactions are still major challenges for their application. Herein, we developed a powerful and functional separator to inhibit the shuttle effect by coating a lightweight three‐dimensional cellulose nanofiber‐derived carbon aerogel on a glass fiber separator (denoted NSCA@GF). The hierarchical porous structures, favorable electronic conductivity, and three‐dimensional interconnected network of N,S‐codoped carbon aerogel endow a multifunctional separator with strong polysulfide anchoring capability and fast reaction kinetics of polysulfide conversion, which can act as the barrier layer and an expanded current collector to increase sulfur utilization. Moreover, the hetero‐doped N/S sites are believed to strengthen polysulfide anchoring capability via chemisorption and accelerate the redox kinetics of polysulfide conversion, which is confirmed from experimental and theoretical results. As a result, the assembled Na–S coin cells with the NSCA@GF separator showed a high reversible capacity (788.8 mAh g−1 at 0.1 C after 100 cycles) and superior cycling stability (only 0.059% capacity decay per cycle over 1000 cycles at 1 C), thereby demonstrating the significant potential for application in high‐performance RT/Na–S batteries. [ABSTRACT FROM AUTHOR]

CoS2/C microprisms with adsorption–catalysis synergistic effects were designed to be sulfur hosts in room-temperature sodium–sulfur batteries. CoS2/C can act as a polysulfide mediator to inhibit the shuttle effect and as a catalyst to accelerate polysulfide redox kinetics, achieving enhanced capabilities of 623 mA h g−1 after 870 cycles at 1 A g−1. [ABSTRACT FROM AUTHOR]