High performance room temperature all-solid-state Na-SexS battery with Na3SbS4-coated cathode via aqueous solution

All-solid-state(ASS)Na-S batteries are promising for large-scale energy storage because of the incombustible solid electrolyte and avoiding the dissolution of intermediates.However,the poor contact between the active material and the solid electrolyte in the positive electrode leads to poor electrochemical performance.Here,we report an aqueous solution approach to fabricate Na3SbS4-coated SexS-based active materials for a Na-S battery working at room temperature.Compared with the Na3SbS4 and SexS mixed cathode,the coated cathode achieves significantly improved Na-ion diffusion kinetics and reduced impedance resistance.Additionally,the nanoparticle coating sustains the volume expansion of the cathode during cycling.The resulting batteries deliver an intensively enhanced specific capacity at various rates.Regardless of the mass loading,the Na3SbS4-coated cathode maintains a decent reversible capacity for the long-term discharge/charge cycling.The best battery achieves an initial discharge capacity of509 mAh g^-1 at a current density of 437.4 mA g^-1 and capacity retention of 98.9%for 100 cycles.To the best of our knowledge,this is one of the best room temperature ASS Na-S battery so far.This work demonstrates that Na3SbS4 is very promising for the cathode coating purpose for ASS Na-S batteries.

Role of Catalytic Materials on Conversion of Sulfur Species for Room Temperature Sodium–Sulfur Battery

Room temperature sodium–sulfur(RT Na-S)battery with high theoretical energy density and low cost has spurred tremendous interest,which is recognized as an ideal candidate for large-scale energy storage applications.However,serious sodium polysulfide shutting and sluggish reaction kinetics lead to rapid capacity decay and poor Coulombic efficiency.Recently,catalytic materials capable of adsorbing and catalyzing the conversion of polysulfides are profiled as a promising method to improve electrochemical performance.In this review,the research progress is summarized that the application of catalytic materials in RT Na-S battery.For the role of catalyst on the conversion of sulfur species,specific attention is focused on the influence factors of reaction rate during different redox processes.Various catalytic materials based on lightweight and high conductive carbon materials,including heteroatom-doped carbon,metals and metal compounds,single-atom and heterostructure,promote the reaction kinetic via lowered energy barrier and accelerated charge transfer.Additionally,the adsorption capacity of the catalytic materials is the key to the catalytic effect.Particular attention to the interaction between polysulfides and sulfur host materials is necessary for the exploration of catalytic mechanism.Lastly,the challenges and outlooks toward the desired design of efficient catalytic materials for RT Na-S battery are discussed.

A novel one-step reaction sodium-sulfur battery with high areal sulfur loading on hierarchical porous carbon fiber

Room temperature sodium-sulfur(RT Na-S)batteries are gaining extensive attention as attractive alternatives for large-scale energy storage,due to low cost and high abundancy of sodium and sulfur in nature.However,the dilemmas regarding soluble polysulfides(Na_(2)Sn,4<n<8)and the inferior reaction kinetics limit their practical application.To address these issues,we report the activated porous carbon fibers(APCF)with small sulfur molecules(S2-4)confined in ultramicropores,to achieve a reversible single-step reaction in RT Na-S batteries.The mechanism is investigated by the in situ UV/vis spectroscopy,which demonstrates Na2S is the only product during the whole discharge process.Moreover,the hierarchical carbon structure can enhance areal sulfur loading without sacrificing the capacity due to thorough contact between electrolyte and sulfur electrode.As a consequence,the APCF electrode with 38 wt%sulfur(APCF-38S)delivers a high initial reversible specific capacity of 1412 mAh g^(-1) and 10.6mAh cm^(-2)(avg.areal sulfur loading:7.5 mg cm^(-2))at 0.1 C(1C=1675 mA g^(-1)),revealing high degree of sulfur utilization.This study provides a new strategy for the development of high areal capacity RT Na-S batteries.

Manipulating metal-sulfur interactions for achieving high-performance S cathodes for room temperature Li/Na-sulfur batteries

Rechargeable lithium/sodium-sulfur batteries working at room temperature(RT-Li/S,RT-Na/S)appear to be a promising energy storage system in terms of high theoretical energy density,low cost,and abundant resources in nature.They are,thus,considered as highly attractive candidates for future application in energy storage devices.Nevertheless,the solubility of sulfur species,sluggish kinetics of lithium/sodium sulfide compounds,and high reactivity of metallic anodes render these cells unstable.As a consequence,metal-sulfur batteries present low reversible capacity and quick capacity loss,which hinder their practical application.Investigations to address these issues regarding S cathodes are critical to the increase of their performance and our fundamental understanding of RT-Li/S and RT-Na/S battery systems.Metal-sulfur interactions,recently,have attracted considerable attention,and there have been new insights on pathways to high‐performance RT-Li/Na sulfur batteries,due to the following factors:(1)deliberate construction of metal-sulfur interactions can enable a leap in capacity;(2)metal-sulfur interactions can confine S species,as well as sodium sulfide compounds,to stop shuttle effects;(3)traces of metal species can help to encapsulate a high loading mass of sulfur with high‐cost efficiency;and(4)metal components make electrodes more conductive.In this review,we highlight the latest progress in sulfide immobilization via constructing metal bonding between various metals and S cathodes.Also,we summarize the storage mechanisms of Li/Na as well as the metal-sulfur interaction mechanisms.Furthermore,the current challenges and future remedies in terms of intact confinement and optimization of the electrochemical performance of RT-Li/Na sulfur systems are discussed in this review.

Reasonable suppression of polysulfides/polyselenides shuttle based on MXene in Na-SeS_(2)batteries

Metal-sulfur/selenium batteries have become the focus of new-generation energy storage systems due to the advantages of low-cost and high energy density.However,it still suffers from the notorious shuttle of polysulfides/polyselenides,poor electronic conductivity and tremendous volume expansion.Herein,a dual defense system for polysulfides/polyselenides was proposed and constructed based on MXene.The nitrogen-doped porous carbon(NPC)decorated by Ti_(3)C_(2)T_(x)MXene(M@NPC)was employed as the SeS_(2)host(SeS_(2)@M@NPC).Particularly,Ti_(3)C_(2)T_(x)sheets wrapped on NPC guarantee the rapid ion diffusion and serve as the first barrier for SeS_(2)and dissolved sodium polysulfides/polyselenides.Meanwhile,the few-layered Ti_(3)C_(2)T_(x)sheets coated on glass fiber separators act as the second barrier for alleviating the shuttle of polysulfides/polyselenides through physical interception and chemical adsorption.With this elaborate design,the integrated Na-SeS_(2)battery achieves a high specific capacity of 1243 mAh·g^(-1)at 1.0C,revealing a distinct superiority over its counterparts(SeS_(2)@M@NPC,1083mAh·g^(-1)at 0.5C;and SeS_(2)@NPC,823 mAh·g^(-1)at 0.5C).The findings gained in this work provide a creative idea for the construction of durable room-temperature Na-SeS_(2)batteries based on MXenes and their derivative materials.