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Rechargeable aqueous batteries are promising energy storage devices because of their high safety and low cost. However, their energy densities are generally unsatisfactory due to the limited capacities of ion‐inserted electrode materials, prohibiting their widespread applications. Herein, a high‐energy aqueous all‐sulfur battery was constructed via matching S/Cu2S and S/CaSx redox couples. In such batteries, both cathodes and anodes undergo the conversion reaction between sulfur/metal sulfides redox couples, which display high specific capacities and rational electrode potential difference. Furthermore, during the charge/discharge process, the simultaneous redox of Cu2+ ion charge‐carriers also takes place and contributes to a more two‐electron transfer, which doubles the capacity of cathodes. As a result, the assembled aqueous all‐sulfur batteries deliver a high discharge capacity of 447 mAh g−1 based on total mass of sulfur in cathode and anode at 0.1 A g−1, contributing to an enhanced energy density of 393 Wh kg−1. This work will widen the scope for the design of high‐energy aqueous batteries. [ABSTRACT FROM AUTHOR]

The energy densities of conventional aqueous batteries are often unsatisfactory due to the limited capacities of electrode materials.Therefore, the design of creative aqueous batteries has to be considered. Herein, aqueous S-MnO2 batteries are constructed by matching S/Cu2S redox couples and MnO2 deposition/dissolution. In such batteries, S/Cu2S redox couples undergo the solid-solid conversion reaction with four-electron transfer, ensuring a high specific capacity of 2220 mAh g-1 in S anodes.Furthermore, the conversion reaction of S/Cu2S redox couples can take place stably in acidic electrolyte that is essential for the MnO2 deposition/dissolution. As a result, the S/Cu2S redox couples can match MnO2 deposition/dissolution well, which endow the batteries with a membrane-free configuration. As a proof of concept,  Ah-level prismatic and single-flow batteries were assembled and could operate stably for over 1000 h, demonstrating their great potential for large-scale energy storage. This work broadens the horizons of aqueous batteries beyond metal-manganese chemistry., (© 2024 Wiley‐VCH GmbH.)

High‐energy density and ultra‐long cycling lifespan are of great significance in pursuit of practical lithium–sulfur (Li‐S) batteries, in which the construction of ultrathick, high‐areal‐capacity, and stable‐cycling sulfur cathodes remains challenging. Here, a unique layered reinforced concrete structure (LRCS) is reported by integrating an ice‐template method with incorporating carbon fibers in the thick electrodes for Li‐S batteries. The LRCS enables aligned through‐channel structure and intertwined conductive network, which lead to both fast kinetics of ions/electrons transport and strengthened electrode integrity to tolerate the volume change during cycling and the dimensional deformation under a high compaction density. Benefiting from the unique structure, the ultra‐thick Se0.05S0.95 @ pPAN cathode (20.2 mg cm−2) delivers a high capacity of 10 mAh cm−2 and excellent capacity retention of 80.8% over 140 cycles at a low electrolyte‐to‐sulfur ratio of 2 and a negative‐to‐positive capacity ratio of 2.7, corresponding to a calculated energy density of 390 Wh kg−1. This investigation not only provides guidance for the design of thick sulfur electrodes but also paves the way for the development of practical Li‐S batteries. [ABSTRACT FROM AUTHOR]

Lithium–sulfur batteries are deemed to have the opportunity to replace lithium‐ion batteries because of their high energy density. Nonetheless, the shuttling of soluble long‐chain polysulfides severely deteriorates the cyclic performances of the batteries. Herein, an encapsulated sulfur electrode to tackle the shuttle effect is designed. This high‐performance electrode is fabricated by encapsulating the active sulfur inside a sealing configuration composed of lithiated Nafion (Li‐Nafion), carbon black (BP2000), and a binder of polytetrafluoroethylene. The dense surface of the encapsulated configuration can physically obstruct the mobility of soluble polysulfides. Meanwhile, the sulfonic acid groups fixed on the Li‐Nafion backbone provide a robust electrostatic repulsion to inhibit the negatively charged polysulfides from migrating into the electrolyte. Therefore, the encapsulated sulfur electrode delivers 522.6 mAh g−1 at the 600th cycle with a retention of 80.36%, exhibiting a more competitive cyclic stability than the pristine sulfur electrode. [ABSTRACT FROM AUTHOR]

The room‐temperature (RT) Na/S battery is a promising energy storage system owing to suitable operating temperature, high theoretical energy density, and low cost. However, it has a poor cycle life and low reversible capacity. In this work, we report a long‐life RT‐Na/S battery with amorphous porous silica as a sulfur host. The sulfur is loaded into amorphous silica by a dipping method; the optimal sulfur loading is up to 73.48 wt %. Molecular dynamics simulation and first‐principles calculations suggest that the complex pores, acting as micro‐containers and the formation of Na‐O chemical bonds between amorphous silica and sodium polysulfide, give the electrodes a strong ability to inhibit sodium polysulfide shuttle. This would give rise to effectively avoiding the loss of active sulfur, corresponding to a superior capacity and an excellent cyclability even at 10 A gsulfur−1 (nearly 100 % coulomb efficiency and high reversible capacity of 955.8 mAh gsulfur−1 after 1460 cycles). [ABSTRACT FROM AUTHOR]

The mechanism of the cathodic reduction of sulfur is studied via cyclic voltammetry. An analysis of cyclic voltammograms using normalized coordinates shows that insoluble products (particularly Li2S2) form not as a result of an electrochemical process, but due to the disproportionation of Li2S4. The degradation of sulfur electrodes during cycling is associated with incomplete oxidation of the products of the cathodic reaction to elemental sulfur. [ABSTRACT FROM AUTHOR]

We present a sulfur‐layered carbon electrode, a new configuration of sulfur cathode, which is constructed by a two‐step slurry‐casting process. The LiS cells employing the new sulfur cathode normally operate with large capacities. Sulfur particles on the carbon layer are not visible upon discharging to 2.1 V in the first discharge, indicating that electrically isolated sulfur is participated in the electrochemical reactions at the carbon surface. This strategy will bring about a paradigm shift in the design of high‐performance sulfur cathodes and open new perspectives in the low‐cost manufacturing of sustainable LiS cells. [ABSTRACT FROM AUTHOR]

The presence of electrocatalysis in lithium–sulfur batteries has been proposed but not yet sufficiently verified. In this study, molybdenum phosphide (MoP) nanoparticles are shown to play a definitive electrocatalytic role for the sulfur cathode working under lean electrolyte conditions featuring a low electrolyte/active material ratio: the overpotentials for the charging and discharging reactions are greatly decreased. As a result, sulfur electrodes containing MoP nanoparticles show faster kinetics and more reversible conversion of sulfur species, leading to improvements in charging/discharging voltage profiles, capacity, rate performance, and cycling stability. Taking advantage of the electrocatalytic properties of MoP, high‐performance sulfur electrodes were successfully realized that are steadily cyclable at a high areal capacity of 5.0 mAh cm−2 with a challenging electrolyte/sulfur (E/S) ratio of 4 μLE mg−1S . [ABSTRACT FROM AUTHOR]

Abstract Change in the content of lithium sulfide is quantitatively studied through the methods of precipitation and back iodometric titration in lithium-sulfur cells during charge-discharge cycling for 100 cycles. It is shown that in the initial cycles (25 cycles) of charge-discharge cycling, electrochemically inactive lithium sulfide accumulates. The predominantly inactive lithium sulfide accumulates in the sulfur electrode. It is likely that lithium sulfide is deposited in the pores of the carbon material, blocks the pores and loses the ability to participate in the electrochemical reactions. On the surface of the lithium electrode, a surface layer containing lithium sulfide is formed during the cycling of the lithium-sulfur cells and is in equilibrium with the electrolyte system. It is found that lithium sulfide does not accumulate on the lithium electrode for at least 100 charge-discharge cycles. Graphical abstract Image 1 Highlights • Lithium sulfide content in Li-S cells is studied. • Lithium sulfide does not accumulate on lithium electrodes over 100 cycles. • Lithium sulfide is blocked in the pores of carbon particles of positive electrode. [ABSTRACT FROM AUTHOR]

Abstract: We have designed and synthesized novel hollow Ni/Fe layered double hydroxide (LDH) polyhedrons as an advanced sulfur host for enhancing the performance of lithium–sulfur (Li–S) batteries. The Ni/Fe LDH host shows multiple advantages. First, the Ni/Fe LDH shells can provide sufficient sulfiphilic sites for chemically bonding with polysulfides. Second, the hollow architecture can provide sufficient inner space for both loading a large amount of sulfur and accommodating its large volumetric expansion. Moreover, once the active material is confined within the host, the shells could easily restrict the outward diffusion of polysulfides, guaranteeing prolonged cycle life even with high sulfur loading. As a result, the S@Ni/Fe LDH cathode has successfully solved the main issues related to sulfur electrodes, and it exhibits significantly improved electrochemical performances with prolonged life over 1000 cycles and excellent rate properties. [ABSTRACT FROM AUTHOR]

Abstract: Ambient‐temperature sodium–sulfur (Na–S) batteries are considered a promising energy storage system due to their high theoretical energy density and low costs. However, great challenges remain in achieving a high rechargeable capacity and long cycle life. Herein we report a stable quasi‐solid‐state Na‐S battery enabled by a poly(S‐pentaerythritol tetraacrylate (PETEA))‐based cathode and a (PETEA‐tris[2‐(acryloyloxy)ethyl] isocyanurate (THEICTA))‐based gel polymer electrolyte. The polymeric sulfur electrode strongly anchors sulfur through chemical binding and inhibits the shuttle effect. Meanwhile, the in situ formed polymer electrolyte with high ionic conductivity and enhanced safety successfully stabilizes the Na anode/electrolyte interface, and simultaneously immobilizes soluble Na polysulfides. The as‐developed quasi‐solid‐state Na‐S cells exhibit a high reversible capacity of 877 mA h g−1 at 0.1 C and an extended cycling stability. [ABSTRACT FROM AUTHOR]

Abstract: Li–S batteries have received tremendous attention owing to their high theoretical capacity (1672 mA h g−1), sulfur abundance, and low cost. However, main systemic issues, associated with polysulfide shuttling and low Coulombic efficiency, hinder the practical use of the sulfur electrode in commercial batteries. Herein, we demonstrate an effective strategy of decorating nano‐MnO2 (less than 10 wt %) onto the sulfur reservoir to capture the out‐diffused polysulfides through chemical interaction and thereby improve the electrochemical performance of the sulfur electrode without increasing the mass burden of total battery configuration. Pistachio shell‐derived sustainable carbon (PC) was employed as effective sulfur containers owing to its structural characteristics (interconnected macro channels and micropores). With the aids of the structural benefits of the PC scaffold and the uniform decoration of nano‐MnO2, polysulfide shuttling was significantly suppressed and the cycling performance of the sulfur cathode was dramatically improved over 250 cycles. [ABSTRACT FROM AUTHOR]

In the present paper electrochemical leaching has been applied to recover gold from the gold concentrate (Vasilkovskoe deposit, Kazakhstan) into water solution. The specially prepared sulfur-graphite electrode (SGE) was used as a source of sulfurcontaining anions, acting as leaching agents. To prevent anodic oxidation of sulfur-containing anions, the cathodic compartment was separated from the anodic one with PVC separator. Cathodic polarization of SGE immersed into NaOH aqueous solution in the presence of gold concentrate leads to gold partial recover into solution. The following leaching process conditions allow to obtain maximum gold recovery (93 %): CNaOH = 2 M; i = 80 mA cm-2; L:S = 7; leaching duration = 210 min. The SGE consumption is about 55 g per 1 g of the gold in the solution under the above-mentioned conditions. [ABSTRACT FROM AUTHOR]

Abstract: As one of the important ingredients in lithium‐sulfur battery, the binders greatly impact the battery performance. However, conventional binders have intrinsic drawbacks such as poor capability of absorbing hydrophilic lithium polysulfides, resulting in severe capacity decay. This study reports a new type of binder by polymerization of hydrophilic poly(ethylene glycol) diglycidyl ether with polyethylenimine, which enables strongly anchoring polysulfides for high‐performance lithium sulfur batteries, demonstrating remarkable improvement in both mechanical performance for standing up to 100 g weight and an excellent capacity retention of 72% over 400 cycles at 1.5 C. Importantly, in situ micro‐Raman investigation verifies the effectively reduced polysulfides shuttling from sulfur cathode to lithium anode, which shows the greatly suppressed shuttle effect by the polar‐functional binder. X‐ray photoelectron spectroscopy analysis into the discharge intermediates upon battery cycling reveals that the hydrophilic binder endows the sulfur electrodes with multidimensional Li‐O, Li‐N, and S‐O interactions with sulfur species to effectively mitigate lithium polysulfide dissolution, which is theoretically confirmed by density‐functional theory calculations. [ABSTRACT FROM AUTHOR]

Abstract: Lithium–sulfur (Li–S) batteries have the potential to be as efficient and as widespread as lithium‐ion (Li‐ion) batteries, since sulfur electrode has high theoretical capacity (1672 mA h gsul−1) and this element is affordable. However, unlike their ubiquitous lithium ion (Li‐ion) counterparts, it is difficult to realize the commercialization of Li‐S battery. Because the shuttle effect of polysulfide inevitably results in the serious capacity degradation. Tremendous progress is devoted to approach this problem from the aspect of physical confinement and chemisorption of polysulfide. Owing to weak intermolecular interactions, physical confinement strategy, however is not effective when the battery is cycled long‐term. Chemisorption of polysulfide that derived from polar–polar interaction, Lewis acid–base interaction, and sulfur‐chain catenation, are proven to significantly suppress the shuttle effect of polysulfide. It is also discovered that the metal compounds have strong chemical interactions with polysulfide. Therefore, this review focuses on latest metal–organic frameworks metal sulfides, metal hydroxides, metal nitrides, metal carbides, and discusses how the chemical interactions couple with the unique properties of these metal compounds to tackle the problem of polysulfide shuttle effect. [ABSTRACT FROM AUTHOR]

Abstract: Lithium‐sulfur batteries are a promising alternative to lithium‐ion batteries due to their low weight and the high availability of sulfur. In addition to research on material aspects, scalable processes are needed to manufacture tailored sulfur cathodes with high‐energy densities. Therefore, this work focuses on the usage of mechanical processes to prepare defined carbon‐sulfur composite materials that are subsequently processed to electrodes. DEM simulations are used to calculate the necessary power input and the resulting stress energy for different mechanical processes. [ABSTRACT FROM AUTHOR]

Amorphous phase TiO 2 nanotube (NT) arrays as sulfur reservoir are fabricated by anodization method on Ti plate used as current collector. Properties of the NT arrays before heat-treatment are evaluated with those after heat-treatment for applicability as a reservoir and conductor of sulfur electrode. A reasonably high amount of sulfur is loaded (14.8%) from 30% feed sulfur solution at 160 °C in the candidate NT array chosen as the sulfur reservoir. Three electrodes from the only NT array, the sulfur-loaded NT array with and without coating layer are evaluated on electrochemical performances. The sulfur electrode with coating layer, consisting of super-P and PVdF, exhibits the highest initial and retention capacity in discharge, respectively, of 1547 mAh g −1 and 1085 mAh g −1 up to 100 cycles. Rate capability at various C-rates from 0.1 to 30 C is also found to be exceptionally good. [ABSTRACT FROM AUTHOR]

Practical lithium-sulfur batteries require high sulfur electrode loading and lean electrolyte designs, which entail more research efforts on the two cell-design parameters - sulfur loading and electrolyte/sulfur loading ratio (E/S). In this work, a systematic investigation is performed to understand the impact of these two variables over key Li-S cell performance parameters. It is demonstrated that Li-S cell's power performance strongly depends on the E/S ratio, while both E/S ratio and sulfur loading significantly influence the cycle life of Li-S cells. Low E/S ratio and high sulfur loading both give rise to fast lithium anode corrosion, which induces fast capacity fade and Coulombic efficiency decay. Pre-passivation of the lithium anode with an ionic conductor Li3PO4 protection layer only improves the Coulombic efficiency retention at sulfur loading levels much lower than the practical threshold. Meanwhile, increasing the concentration of LiNO3 additive in the electrolyte is found effective in sustaining the cycling capacity and the Coulombic efficiency over a reasonable usage window (∼200 cycles). The role of LiNO3 is the protection of lithium anode during cycling. [ABSTRACT FROM AUTHOR]

A designed custom glyme ether with unsymmetrical (ethyl and butyl) end groups (UG) has been shown to give highly conducting liquid solvate electrolytes. Solvates prepared with UG glyme: salt ratios of 1:1, 2:1, and 3:1 using lithium bis(trifluoromethane sulfonyl) imide (LiTFSI) and lithium bis(fluoro sulfonyl) imide (LiFSI) lithium salts have been characterized with emphasis on the 2:1 composition. Conductivity in the order of 10-3 S/cm was observed at room temperature with an electrochemical stability window of 4.5 V. DSC studies indicate a low crystallization temperature between -60 °C and -75 °C for LiFSI based solvate electrolyte. Galvanostatic cycling studies (C/10) with LiFePO4 electrodes indicate a capacity deliverance of 145 mAh/g and good C-rate capability up to 2C at room temperature. Preliminary tests using unsymmetrical glyme-based solvate electrolytes with sulfur and LiNi1/3Mn1/3Co1/3O2 (NMC) electrodes reveal a low degree of polysulfide dissolution with sulfur electrodes and stable voltage profiles with NMC electrodes suggesting the use of these electrolytes for Li/S batteries and high-voltage Li-ion batteries. [ABSTRACT FROM AUTHOR]

Lithium sulfur batteries have been regarded as next-generation battery technology due to its high energy density, environmental benignity and abundance. However, the poor electric/ionic conductivity of sulfur limits the practical use of sulfur in an electrode. The main problem is the high solubility of long-chain polysulfides, which are the intermediates of the electrochemical processes in the liquid electrolyte. The dissolved polysulfide ions shuttle between the cathode and anode, thus causing precipitation of insulating Li 2 S 2 /Li 2 S on the surface of the electrode. The unavoidable phenomenon results in loss of active materials and fast capacity fading. In this regard, we show one simple method to prepare free-standing paper electrode used as cathode material for lithium sulfur batteries. Binder-free graphene-polypyrrole (PPy)/S-graphene (G-PPy/S-G) paper-like sandwich structural electrode was prepared by using the vacuum filtration method. In this structure, the unique graphene layers of sandwich-like framework not only serve as a conductive film, but also effectively block the diffusion of polysulfides, leading to suppression of the shuttle effect and low self-discharge behaviour. In addition, the middle layer, the PPy nanofibers can limit the diffusion of dissolved polysulfides due to the special bond with sulfur, and furthermore maintain the structural stability of the paper electrode because the nanofibers can serve as elastic springs to accommodate the huge volume changes in charging-discharging processes. When tested as cathode for Li-S batteries, the as-prepared sample G-PPy/S-G exhibits excellent electrochemical performance. We believe that our strategy could provide a useful pathway towards commercial utilizing of sulfur. [ABSTRACT FROM AUTHOR]

Composite sulfur electrodes are prepared by high-temperature mechanical milling (443 K) for use in all-solid-state lithium–sulfur batteries, and their structures and electrochemical properties are investigated. Composites comprising sulfur, acetylene black, and a Li 3.25 Ge 0.25 P 0.75 S 4 solid electrolyte are fabricated by planetary ball milling using a temperature-controlled system. The composite electrode exhibits a high discharge capacity of greater than 1200 mAh g −1 and a good cycle capability. As a result of high-temperature milling, composites are formed, incorporating novel structural units from the reaction between sulfur and the solid electrolyte, along with their intrinsic characteristics. Hence, high-temperature milling demonstrates promise for the fabrication of a composite electrode exhibiting high, reversible electrochemical activities for use in an all-solid-state lithium–sulfur battery. [ABSTRACT FROM AUTHOR]

All-solid-state Na/S cells with high safety, capacity, and low material costs are desirable for smart grid systems. We report sulfur composite electrodes prepared by the mechanical milling of sulfur, Ketjen black, and P 2 S 5 or Na 3 PS 4 for high-capacity cells. A cell using P 2 S 5 , which is not ion conductive, in the sulfur electrode exhibits a high reversible capacity of 340 mAh (g‑sulfur electrode) − 1 at 0.04 C rate at 25 °C, which is much larger than that (37.3 mAh (g‑sulfur electrode) − 1 ) obtained in a conventional cell using a high ion-conductive Na 3 PS 4 electrolyte. To investigate the reaction mechanism of the sulfur composite electrode containing P 2 S 5 , X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) measurements and scanning and transmission electron microscopy (SEM/TEM) observations of the electrodes were conducted. The results indicate that a crystalline Na 3 PS 4 component is automatically produced by the electrochemical reaction with Na in the amorphous S-P 2 S 5 electrode and it mixing with the sulfur redox parts at the nanoscale. The mixing degree is higher than that at microscale in the conventional S-Na 3 PS 4 electrode, which results in the high capacity of the cells containing the S-P 2 S 5 electrode. Partial substitution of P 2 S 5 for SiS 2 in the sulfur electrode suppresses the nanocrystallization and further increases the reversible capacity up to 390 mAh (g‑sulfur electrode) − 1 under 0.04 C rate, which is the highest in reported all-solid-state Na batteries to date. [ABSTRACT FROM AUTHOR]

A cathode was prepared by sealing a carbon supported sulfur electrode inside a composite ion-selective net made of carbon, binder and lithiated ionomer to restrict shuttling of polysulfide anionic species. As a result, the soluble polysulfide anions become unable to escape from the composite ion-selective films due to the electrostatic repulsion between the immobilized single ion conducting ionomers and the polysulfides with no dead angles. Experimentally, lithiated 4,4′-difluoro bis(benzene sulfonyl)imide and PEG200 were copolymerized to form a polyether based single ion conducting polymer. The ionic conductivity of the blend film made of ionomer and poly(vinylidene fluoride- co -hexafluoropropylene) (PVDF-HFP) at a mass ratio of 1:1 is 0.57 mS cm −1 at room temperature. The battery capacity with the sealed sulfur electrode is 1412 mAh g −1 at 0.5 C, 1041 mAh g −1 at 1.0 C, 873 mAh g −1 at 2.0 C and 614 mAh g −1 at 5.0 C, significantly better than the results with lithiated Nafion especially at high C rates. In addition, a long cycling test at 2 C for 500 cycles gives rise to a stable capacity of 800 mAh g −1 . The intrinsic electrostatic repulsion between polysulfide anions and the negatively charged electrolyte film, together with the overall sealed electrode configuration, is responsible for blocking the shuttling of polysulfides effectively. [ABSTRACT FROM AUTHOR]

The high energy lithium-sulfur batteries have received more attention for next-generation energy storage; however, low conductivity of the sulfur cathode and shuttle of polysulfides still limit the utilization of sulfur. To optimizing sulfur utilization and improving the cycling lifespan of Li-S cells, we report a three-dimensional hierarchical porous N-doped graphene (NG) assisted sulfur cathode and its coated separator for high performance of Li-S batteries. In particular, the formation of the novel 3D structure is inspired from the combination of active hydrothermal releasing gas and cohesive action from in situ polymerization of pyrrole. The as prepared 3D N-doped graphene/S composite containing 75 wt% sulfur delivers reversible capacity of 582.7 mAh g −1 after 200 cycles at 0.2 C with capacity retention rate of 79.5%. The as-developed 3D N-doped graphene coated on separator as an interlayer could not only enhance the charge-transfer network of cathode but also protect the Li anode from been destroyed. The interlayer cell confirmed enhanced the cycling performance with reversible capacity of 851.8 mAh g −1 after 200 cycles at 0.2 C and retain 88.7% of its maximum discharging capacity (666.8 mAh g −1 ) after 300 cycles at 0.5 C, suggesting potential strategy to tackle the fundamental challenges underlying high sulfur loading Li-S batteries. [ABSTRACT FROM AUTHOR]

The carbon aerogel (CA) uniformly doped neodymium oxide (Nd 2 O 3 ) nanoparticle was synthesized by an effective in-situ method via acid catalyzing and used as the cathode matrix for lithium-sulfur batteries. The doped materials with interconnected pore structure of CA and evenly dispersed Nd 2 O 3 offer crucial confinement role to anchor sulfur and suppress the loss of polysulfide ions for interrelate function of S/polysulfides by Nd 2 O 3 . The composited sulfur electrodes present high electrochemical performances and initial discharge capacities, especially, the Nd2-CA/S sample gains initial discharge capacity of 1327 mAh g − 1 at 0.2 C and remains at 1082 mAh g − 1 after 100 cycles. Meanwhile, it still remains capacity of about 907 mAh g − 1 at 0.5 C after 300 cycles. The enhanced electrochemical performances can be ascribed to the crosslink mesoporous CA materials and well distributed neodymium oxide. Furthermore, the metal additive also takes promoting effect on redox reactions of the Li/S batteries presenting higher discharge voltages. [ABSTRACT FROM AUTHOR]

A metal hydride is used for the first time as anode in a complete all-solid-state battery with sulfur as cathode and LiBH 4 as solid electrolyte. The hydride is a nanocomposite made of MgH 2 and TiH 2 counterparts. The battery exhibits a high reversible capacity of 910 mAh g −1 with discharge plateaus at 1.8 V and 1.4 V. Moreover, the capacity remains to 85% of the initial value over the 25 first charge/discharge cycles. [ABSTRACT FROM AUTHOR]

Sulfur cathodes have attracted much attention recently because of their high energy density and power density. However, sulfur possesses very poor electrical conductivity, and lithium polysulfides, resulting from the lithiation of sulfur, are prone to dissolving into electrolytes, which leads to the loss of active materials and poor cyclic performance of the sulfur cathodes. Here we report an MnO 2 -graphene oxide (GO) double-shelled sulfur (S@MnO 2 @GO) with improved rate capability and cyclic performance, in which we propose a new reaction using sulfur-reducing KMnO 4 to produce MnO 2 that covers the surface of the excess sulfur in situ . The resulting MnO 2 with honeycomb-like morphology provides excellent voids for storing polysulfides. The outermost GO was assembled to block the open pores of MnO 2 , thereby minimizing the opportunity for polysulfides to leach into the electrolytes. The GO significantly improved the electrical conductivity of the sulfur cathode, and the S@MnO 2 @GO exhibited excellent rate capability and long cycle life. [ABSTRACT FROM AUTHOR]

Hierarchical porous hollow carbon microstructures (HPHCMs) have been successfully prepared from the cheap and abundant natural resource of oil palm shells, which are a well-known host material for the sulfur electrode in Li–S batteries. In this preparation, the hollow tracheids are chemically isolated from oil palm shells, further heat-treated at 400 °C for carbonization and then calcined at 800 °C with KOH/K2CO3 for activation. In Li–S batteries, the as-prepared HPHCMs are loaded with 60 wt% sulfur to form the cathode material, which delivers an initial specific capacity of 1105 mA h g−1 and a high capacity retention of 74%, even after 100 cycles. Thus, this investigation provides a facile method for preparing hierarchical porous hollow carbon microstructures from plant tracheids, which can be applied excellently as electrode materials. [ABSTRACT FROM AUTHOR]

We explore the influence of coverage percentage of the sulfur electrode on the cycle performance of lithium-sulfur batteries. Four sulfur electrodes covered with composite films made of carbon (BP2000), nano-Al 2 O 3 and polytetrafluoroethylene (PTFE) with different exposure are prepared and tested in lithium-sulfur batteries. The results display that both the capacity retention and coulombic efficiency are improved with the increase of surface coverage percentage among which the cell with the completely sealed sulfur electrode exhibits the best cycle performance. The discharge capacity of the sealed sulfur electrode is ca. 800 mAh g −1 after 1000 cycles at 2 C with capacity retention over 77%. The ex-situ field emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), Ultraviolet–Visible spectroscopy (UV) and nitrogen sorption measurements reveal that the sealed structure with narrow and irregular interstitials effectively suppresses the diffusion of soluble polysulfides out of the embraced environment with virtually no effect on lithium ion conduction. The present study demonstrates the effectiveness of the sealed structure for achieving robust electrochemical performance of lithium-sulfur batteries. [ABSTRACT FROM AUTHOR]

The honeycomb-like hierarchical porous carbon nanofibers (PCNFs)-carbon nanotubes (CNTs)-sulfur(S) composite electrode is successfully desgined and prepared through ball-milling and heating method, in which the PCNFs are carbonized from fibers in the membrane composed of Polyvinyl Alcohol and Polytetrafluoroethylene by electro-blown spinning technology. The prepared PCNFs-CNTs-S composite are regarded as cathode for lithium-sulfur battery. The tailored porous structure and CNTs in the composite facilitate construction of a high electrical conductive pathway and store more S/polysulfides, and the dissoluble loss of intermediate S species in electrolyte can also be restrained because of acidized PVA-based porous carbon nanofibers. Meanwhile, the porous strcucture and CNTs can effectively alleviate volume changes in battery cycling process. Moreover, the presence of LiNO 3 in electrolyte helps the electrochemical oxidation of Li 2 S and LiNO 3 -derived surface film effectively suppresses the migration of soluble polysulfide to the Li anode surface. Therefore, the obtained PCNFs-CNTs-S cathode exhibits excellent performance in Li-S battery with a high initial discharge capacity as high as 1302.9 mAh g −1 , and super stable capacity retention with 809.1 mAh g −1 after 300 cycles at the current density of 837.5 mA g −1 (0.5 C). And the rate capability of PCNFs-CNTs-S electrode is much better than those of CNTs-S and PCNFs-S electrodes. [ABSTRACT FROM AUTHOR]

This work reports the preparation of 3D porous nickel-sulfur electrode for hydrogen evolution reaction (HER). The construction of the 3D porous structure is achieved by hydrogen bubbles dynamic templates, prepared from Cu electrodeposition at high current density. Subsequently, a nickel-sulfur film is electrodeposited on the 3D porous copper structure. The nickel-sulfur film with high crystal Ni 3 S 2 content is achieved only through controlling deposition current. And the relationship between crystal structure and deposition current has been revealed. The porous crystal Ni 3 S 2 electrode is significantly active for HER with a lower onset overpotential and an additional negative potential leading to a rapid increase in the cathodic current. And the developed electrode shows a lower charge transfer resistance for HER, which takes both advantages of high intrinsic activity and large real surface area. Besides, the electrode shows a higher electrochemical stability during the long-term electrolysis test. [ABSTRACT FROM AUTHOR]

Lithium-sulfur (Li-S) batteries are considered as an attractive electrochemical energy storage system due to the high theoretical capacity of sulfur (1,675 mA h g −1 ). However, high-loading sulfur cathodes would need to be employed for the Li-S cells to be practical, but the resulting poor cell cyclability and severe electrode degradation hamper their development. Here, we present a hierarchical sulfur cathode as a testing platform for understanding the high-loading capability of Li-S batteries. The hierarchical cathode presents good electrochemical utilization of above 70%, stable cyclability for 500–1,000 cycles, and high sulfur loadings of 4.2–10.0 mg cm −2 . The exploration of the activation and the polysulfide-retention processes of the high-loading cathodes illustrates that the electrochemical stability mainly results from the stabilization of dissolved polysulfides within the cathode region as the electrochemically active catholyte. Therefore, the utilization of stabilized polysulfide migration might be a meaningful opportunity for designing high-loading cathodes and further improving their electrochemical stability and long-term cyclability. [ABSTRACT FROM AUTHOR]

Polysulfide (PS) shuttle, which is one of the critical problems that need to be addressed for realizing lithium sulfur batteries, can be suppressed by confining PSs within microporous or mesoporous templates. However, PS dissolution through the external opening of the templates has to be further prevented. In this work, a poly (3,4-ethylenedioxythiophene) (PEDOT) layer is formed in situ on the CMK-3/S cathode by inducing the electro-oxidative polymerization of the EDOT monomer included in electrolytes during pre-charging. The PEDOT layer covering the external cathode surface functions as a PS blocking layer, which suppresses the PS shuttle and, thus, improves the cycling stability. The spectroscopic analysis indicates that the PEDOT layer reduces the decomposition of the electrolyte by preventing any reaction between the active PS species and electrolytes. Therefore, the in situ formation of the PS blocking layer from the electrolyte additive provides a simple and effective method to improve the cycling stability of lithium sulfur batteries. [ABSTRACT FROM AUTHOR]

The effects of solvents on the preparation of sulfur cathodes were investigated by fabricating binder-free sulfur electrode films using three different solvents: 1-methyl-2-pyrrolidinone (NMP), acetonitrile, and deionized water. These solvents are commonly employed to dissolve binders used to prepare sulfur cathodes for lithium–sulfur batteries. The sulfur electrode fabricated with NMP had a higher discharge capacity and longer cycle life than the ones fabricated with acetonitrile and deionized water. Better adhesion between the current collector and the sulfur electrode accounted for the improved capacity and cycle life of the battery. In addition, the stability of the electrode in the electrolyte was a result of the solubility of sulfur in the solvent. We thus concluded that the solvents used in the fabrication of sulfur electrodes had a positive influence on the electrochemical properties of Li–S batteries. [ABSTRACT FROM AUTHOR]

A mixed conductive coating layer composed of lithium ion conductive ceramic powder, carbon and binder was introduced on the surface of a sulfur electrode. This coating layer is designed to suppress the migration of lithium polysulfides from the sulfur electrode, and improve the cycling capacity of a lithium sulfur battery. The protected sulfur cathode with a mixed conductive coating layer delivered an initial specific capacity of 1236 mAh g at 0.5C and maintained a capacity of 842 mAh g after 100 cycles. In particular, a soft package battery with protected cathode exhibits improved cycling capacity and excellent rate performance. [ABSTRACT FROM AUTHOR]

Room-temperature sodium-sulfur (RT-Na/S) batteries possess high potential for grid-scale stationary energy storage due to their low cost and high energy density. However, the issues arising from the low S mass loading and poor cycling stability caused by the shuttle effect of polysulfides seriously limit their operating capacity and cycling capability. Herein, sulfur-doped graphene frameworks supporting atomically dispersed 2H-MoS 2 and Mo 1 (S@MoS 2 -Mo 1 /SGF) with a record high sulfur mass loading of 80.9 wt.% are synthesized as an integrated dual active sites cathode for RT-Na/S batteries. Impressively, the as-prepared S@MoS 2 -Mo 1 /SGF display unprecedented cyclic stability with a high initial capacity of 1017 mAh g -1 at 0.1 A g -1 and a low-capacity fading rate of 0.05% per cycle over 1000 cycles. Experimental and computational results including X-ray absorption spectroscopy, in situ synchrotron X-ray diffraction and density-functional theory calculations reveal that atomic-level Mo in this integrated dual-active-site forms a delocalized electron system, which could improve the reactivity of sulfur and reaction reversibility of S and Na, greatly alleviating the shuttle effect. The findings not only provide an effective strategy to fabricate high-performance dual-site cathodes, but also deepen the understanding of their enhancement mechanisms at an atomic level., (© 2022 The Authors. Advanced Materials published by Wiley-VCH GmbH.)

A simple electrospinning methodology is described for generating novel fiber configurations of sulfur with the potential of yielding high performance sulfur electrodes for use in lithium-sulfur batteries. The unique fiber morphology derived by electrospinning has the capability of generating flexible sulfur yarns for the first time rendering them a highly attractive platform for small-scale mobile device applications such as textile-batteries. The electrospinning methodology reported herein also allows for the formation of a polymer-sulfur interface which acts as a physical barrier to liquid lithium electrolyte facilitating the reduction of polysulfide dissolution, a primary barrier to the progress of Li-S systems. Such flexible sulfur wire materials when converted into pellet sulfur electrodes, exhibit very stable capacities over 135 cycles with high areal capacities (∼2.5 mAh cm −2 ). Coating the electrodes with an inorganic lithium ion conductor coating results in further improvement of cycling behavior with electrodes of ∼650 mAh g −1 capacity and an impressive low fade rate of ∼0.003% fade cycle −1 demonstrating the promise of this unique platform. [ABSTRACT FROM AUTHOR]

Porous 3-D current collectors have been shown to be the primary choice in replacing classical 2D aluminum foil in applicable developments, especially those using carbon-based current collectors. In this study, we investigated the impact of using a non-woven carbon (NWC) based current collector for sulfur electrodes, in terms of performance and practical use in a commercial battery, keeping in mind the simplicity of electrode preparation method. The benefits of using NWC as a 3D current collector include high sulfur utilization for even highly loaded electrodes, lower polarization, and the provision of an efficient electrolyte reservoir. High discharge capacities up to ∼1200 mAh g −1 can be obtained at moderate C-rates, with relatively good capacity retention (<1% loss per cycle) and practical loadings as high as 8 mAh cm −2 . [ABSTRACT FROM AUTHOR]

Lithium-sulfur (Li-S) batteries stand as an important candidate for next-generation high-energy secondary batteries due to its high specific capacity, low cost and environmental friendliness. However, practical application of Li-S batteries suffers from low rechargeability, poor rate capability and cycling instability of sulfur cathode, which can be mainly ascribed to the poor conductivity of sulfur and the dissolution of the intermediate polysulfides generated during discharge-charge cycles. In this work, a Nafion/super P-modified dual functional separator is designed to improve the long-term cycle stability and rate capability of the pure sulfur cathode. The electrostatic repulsion between the SO 3 − groups and the dissolved negative S n 2− ions, and the trap and reutilizing effect of super P for polysulfides, provide double insurance to confine the polysulfides within the cathode side, leading to great improvement in both reversible capacity and cycling stability of the sulfur cathode as compared to the battery with pristine Celgard separator. With such dual functional separator, a simple elemental sulfur cathode with 70% S content delivers a high initial discharge capacity of 1087 mAh g −1 at 0.1C and a long-term cyclability with only 0.22% capacity fade per cycle over 250 cycles at 0.5C. [ABSTRACT FROM AUTHOR]

Nitrogen-doped flexible carbon foam was used to fabricate a lithium sulfur battery. The stability and rate performance of the battery were evaluated. The battery with carbon foam calcined at 800 °C displayed superior stability compared with other tested batteries. Battery performance was closely related to the foam structure and component. However, good rate performance was achieved with the foam calcined at 800 °C. Cathodes with carbon foam calcined at different temperatures had diverse effects on the batteries. [ABSTRACT FROM AUTHOR]

This work, for the first time, presents sulfur electrodes for lithium/sulfur (Li/S) batteries produced by a newly developed single-step electroforming process, which allows simultaneous sulfur incorporation during electroformation of an electrically conducting electrode. This metal is used as binding matrix for the sulfur particles and thereby makes any binder and conducting carbon additives redundant. Furthermore, it serves by itself as the current collector, so that all functionalities (current collector, binder and electrical conductor towards sulfur) are fulfilled by the electroformed metal, while modified sulfur particles are directly incorporated (composite electroformation). In this way, the sulfur cathode can be produced in a single continuous step in form of a metal foil with adjustable thickness and sulfur loading. The process requires functionalization of sulfur to improve its wettability, incorporation homogeneity and volume which is provided by wrapping sulfur particles with polythiophene. Electroformed copper-sulfur composite foils are chosen as a first proof of the new concept. The achieved battery capacity, cycling stability and coulombic efficiency are presented. It is shown that the electroformed copper-sulfur composite foil operates very well as a battery cathode and a discharge capacity of over 400 mAh g −1 at a rate of 0.5 C over 100 cycles is preserved. [ABSTRACT FROM AUTHOR]

A novel in situ X‐ray fluorescence microscopy combined with X‐ray absorption spectroscopy technique is reported to investigate the Li–S batteries during electrochemical cycling. The evolution of morphology changes of the electrode is monitored in real time using the X‐ray fluorescence images, while the changes of the sulfur chemical state are characterized simultaneously using the X‐ray absorption spectroscopy spectra. [ABSTRACT FROM AUTHOR]

High energy and cost-effective lithium sulfur (Li-S) battery technology has been vigorously revisited in recent years due to the urgent need of advanced energy storage technologies for green transportation and large-scale energy storage applications. However, the market penetration of Li-S batteries has been plagued due to the gap in scientific knowledge between the fundamental research and the real application need. Here, a facile and effective approach to integrate commercial carbon nanoparticles into microsized secondary ones for application in high loading sulfur electrodes is proposed The slurry with the integrated particles is easily cast into electrode laminates with practically usable mass loadings. Uniform and crack-free coating with high loading of 2-8 mg cm−2 sulfur are successfully achieved. Based on the obtained thick electrodes, the dependence of areal specific capacity on mass loading, factors influencing electrode performance, and measures used to address the existing issues are studied and discussed. [ABSTRACT FROM AUTHOR]

A versatile, cost-effective electrochemical analysis strategy is described that determines the specific Sn2− adsorptivity of materials, and allows prediction of the long-term performance of sulphur composite electrodes in Li–S cells. Measurement of nine different materials with varying surface area, and hydrophobicity using this protocol determined optimum properties for capacity stabilization. [ABSTRACT FROM AUTHOR]

Lithium sulfur batteries have brought significant advancement to the current state-of-art battery technologies due to their high theoretical specific energy of 1675 mAh g −1 . However, the rapid capacity degradation, mainly caused by polysulfide dissolution, remains a significant challenge prior to practical applications. In this work, a sulfur cathode modified by bifunctional nafion/γ-Al 2 O 3 membrane has been successfully prepared, which can remarkably immobilize the polysulfides within the unique cathode structure due to its ions selectivity and absorbent capacity. A high initial discharge capacity of 1448.0 mAh g −1 can be achieved at 1C and 788.6 mAh g −1 preserved after 200 cycles, indicating a slow degradation. Furthermore, the coulombic efficiency maintains as high as 97% during cycling. The excellent electrochemical properties can be attributed to the bifunctional and stable membrane which can dramatically reduce the shuttle effect and keep integrated even after charging–discharging for 200 cycles. [ABSTRACT FROM AUTHOR]

Porous Fe 2 O 3 was prepared by simple annealing of preformed Prussian blue that was synthesized from a wet chemistry method. The obtained porous Fe 2 O 3 nanoparticles were then mixed with sulfur and used as cathode for lithium–sulfur batteries. The porous Fe 2 O 3 acts as an internal polysulfide reservoir, and thus reduces the shuttle effect. Composite cathode containing 5% porous Fe 2 O 3 shows improved cycling performance as compared to that without porous Fe 2 O 3 . A stable reversible discharge capacity of 574.3 mAh/g was obtained after 50 cycles at 0.5 C. [ABSTRACT FROM AUTHOR]

In situ polymerization of acrylonitrile with nano-sulfur particles has been developed as a synthetic route to prepare sulfur/polyacrylonitrile (S/ p PAN) composite as a cathode material for lithium/sulfur battery. Transmission electronic microscopy revealed the formation of a highly developed network structure consisting of PAN and sulfur homogeneous mixing at nanosized level, providing the “buffering” space to accommodate the volume change of sulfur upon cycling and retaining the structural integrity preventing the material agglomeration and degradation. Benefiting from this unique structure, the S/ p PAN composite cathode demonstrated enhanced reversibility, resulting in a discharge capacity of 1177 mAh g −1 at the second cycle and retained about 100% of this value over 100 cycles at 0.5C. Furthermore, the S/ p PAN composite cathode delivered a discharge capacity of 981 mAh g −1 at the 100th cycle at 1C. [ABSTRACT FROM AUTHOR]

The battery community has recently witnessed a considerable progress in the cycle lives of lithium-sulfur (Li-S) batteries, mostly by developing the electrode structures that mitigate fatal dissolution of lithium polysulfides. Nonetheless, most of the previous successful demonstrations have been based on limited areal capacities. For realistic battery applications, however, the chronic issues from both the anode (lithium dendrite growth) and the cathode (lithium polysulfide dissolution) need to be readdressed under much higher loading of sulfur active material. To this end, the current study integrates the following three approaches in a systematic manner: 1) the sulfur electrode material with diminished lithium polysulfide dissolution by the covalently bonded sulfur-carbon microstructure, 2) mussel-inspired polydopamine coating onto the separator that suppresses lithium dendrite growth by wet-adhesion between the separator and Li metal, and 3) addition of cesium ions (Cs+) to the electrolyte to repel incoming Li ions and thus prevent Li dendrite growth. This combined strategy resolves the long-standing problems from both electrodes even under the very large sulfur-carbon composite loading of 17 mg cm−2 in the sulfur electrode, enabling the highest areal capacity (9 mAh cm−2) to date while preserving stable cycling performance. [ABSTRACT FROM AUTHOR]

Utilizing the unparalleled theoreticalcapacity of sulfur reaching1675 mAh/g, lithium–sulfur (Li–S) batteries have beencounted as promising enablers of future lithium ion battery (LIB)applications requiring high energy densities. Nevertheless, most sulfurelectrodes suffer from insufficient cycle lives originating from dissolutionof lithium polysulfides. As a fundamental solution to this chronicshortcoming, herein, we introduce a hierarchical porous carbon structurein which meso- and macropores are surrounded by outer micropores.Sulfur was infiltrated mainly into the inner meso- and macropores,while the outer micropores remained empty, thus serving as a “barricade”against outward dissolution of long-chain lithium polysulfides. Onthe basis of this systematic design, the sulfur electrode delivered1412 mAh/gsulfurwith excellent capacity retention of 77%after 500 cycles. Also, a control study suggests that even when sulfuris loaded into the outer micropores, the robust cycling performanceis preserved by engaging small sulfur crystal structures (S2–4). Furthermore, the hierarchical porous carbon was produced in ultrahighspeed by scalable spray pyrolysis. Each porous carbon particle wassynthesized through 5 s of carrier gas flow in a reaction tube. [ABSTRACT FROM AUTHOR]

The performance of Polymer Electrolyte Membrane Fuel Cell (PEMFC) is highly influenced by the contaminants present in the air, like sulfur compounds, nitrogen compounds, carbon oxides, chlorides etc. In particular, sulfur dioxide (SO2) on the cathode side has a severe effect on the performance of PEMFC. In the present paper we have attempted to mitigate the effect of SO2 poisoned catalyst layer of the fuel cell for both half cell and for single cell using a novel catalyst support. The mitigation strategies for the contaminated MEAs were studied by three different methods viz., electrochemical cycling, increased air stoichiometry and by successive polarization. The platinum on graphene as a catalyst support was found to have a better tolerance towards SO2 contamination when compared with the conventional platinum supported on Vulcan XC carbon catalyst. Electrochemical and single cell contamination tests were done to study the extent of SO2 poisoning on both the catalysts. The sulfur coverage was found to be less for Pt/G based catalyst, around 54% compared with Pt/C. The recovery by successive polarization was found to be better compared to air flow regulation. This may be attributed to the indirect removal of sulfur ions from Pt through scavenged OH- ions. [ABSTRACT FROM AUTHOR]