Cement/Sulfur for Lithium-Sulfur Cells.

Lithium-sulfur batteries represent a promising class of next-generation rechargeable energy storage technologies, primarily because of their high-capacity sulfur cathode, reversible battery chemistry, low toxicity, and cost-effectiveness. However, they lack a tailored cell material and configuration for enhancing their high electrochemical utilization and stability. This study introduces a cross-disciplinary concept involving cost-efficient cement and sulfur to prepare a cement/sulfur energy storage material. Although cement has low conductivity and porosity, our findings demonstrate that its robust polysulfide adsorption capability is beneficial in the design of a cathode composite. The cathode composite attains enhanced cell fabrication parameters, featuring a high sulfur content and loading of 80 wt% and 6.4 mg cm-2, respectively. The resulting cell with the cement/sulfur cathode composite exhibits high active-material retention and utilization, resulting in a high charge storage capacity of 1189 mA∙h g-1, high rate performance across C/20 to C/3 rates, and an extended lifespan of 200 cycles. These attributes contribute to excellent cell performance values, demonstrating areal capacities ranging from 4.59 to 7.61 mA∙h cm-2, an energy density spanning 9.63 to 15.98 mW∙h cm-2, and gravimetric capacities between 573 and 951 mA∙h g-1 per electrode. Therefore, this study pioneers a new approach in lithium-sulfur battery research, opting for a nonporous material with robust polysulfide adsorption capabilities, namely cement. It effectively showcases the potential of the resulting cement/sulfur cathode composite to enhance fabrication feasibility, cell fabrication parameters, and cell performance values.

A solid-state electrolyte for electrochemical lithium-sulfur cells.

Post-lithium-ion batteries are designed to achieve high energy density and high safety by modifying their active material and cell configuration. In terms of the active material, lithium-sulfur batteries have the highest charge-storage capacity and high active-material utilization because of the use of a conversion-type sulfur cathode, which involves conversion between solid-state sulfur, liquid-state polysulfides, and solid-state sulfides. In terms of the configuration, solid-state batteries ensure high safety by using a solid-state electrolyte in between the two electrodes. Herein, we use a lithium lanthanum titanate (LLTO) solid-state electrolyte in the lithium-sulfur cell with a polysulfide catholyte electrode. The LLTO, which replaces the conventional liquid electrolyte, is a solid-state electrolyte that offers smooth lithium-ion diffusion and prevents the loss of polysulfides, while the highly active polysulfide electrode, which replaces the solid-state sulfur cathode, improves the reaction kinetics and the active-material utilization. The material and electrochemical analyses confirm the stabilized electrodes exhibit long-lasting lithium stripping/plating stability and limited polysulfide diffusion. Moreover, the morphologically and electrochemically smooth interface between the solid-state electrolyte and catholyte enables fast charge transfer in the cell, which demonstrates a high charge-storage capacity of 1429 mA h g-1, high rate performance, and high electrochemical efficiency.

Electrolessly tin-plated sulfur nanocomposite for practical lean-electrolyte lithium-sulfur cells with a high-loading sulfur cathode.

Lithium-sulfur batteries are among the most promising low-cost, high-energy-density storage devices. The high-capacity sulfur active material undergoes electrochemical conversion between the solid and liquid states. Thus, the comprehensive design of a suitable synthesis method, substrate material, and cathode configuration is essential for developing advanced sulfur cathodes with practical cell design and cell performance parameters. Herein, an electroless plating method is employed to develop a tin-plated sulfur nanocomposite. The nanosized tin plating shell effectively encapsulates a large amount of sulfur; the nanocomposite exhibits excellent high sulfur loading and content (6-10 mg cm-2 and 65-85 wt%, respectively), and the cell based on the nanocomposite exhibits a superior low electrolyte-to-sulfur ratio of 7-4 µL mg-1. In addition to these critical cell design parameters, the tin-plated sulfur nanocomposite attains outstanding electrochemical utilization and stability for 200 cycles under a broad range of cycling rates of C/20-C/2, and additional outstanding cell performance properties in terms of a high areal capacity of 6.3-11.4 mA h cm-2, a high gravimetric capacity of 520-663 mA h g-1, a high energy density of 13-24 mW h cm-2, and a low electrolyte-to-capacity ratio of 3.75 µL mA h-1.

Rational Design of a High-Loading Polysulfide Cathode and a Thin-Lithium Anode for Developing Lean-Electrolyte Lithium-Sulfur Full Cells.

Lithium-sulfur cells are attractive energy-storage systems because of their high energy density and the electrochemical utilization rates of the high-capacity lithium-metal anode and the low-cost sulfur cathode. The commercialization of high-performance lithium-sulfur cells with high discharge capacity and cyclic stability requires the optimization of practical cell-design parameters. Herein, a carbon structural material composed of a carbon nanotube skeleton entrapping conductive graphene is synthesized as an electrode substrate. The carbon structural material is optimized to develop a high-loading polysulfide cathode with a high sulfur loading capacity (6-12 mg cm-2 ), rate performance (C/10-C/2), and cyclic stability for 200 cycles. A thin lithium anode based on the carbon structural material is developed and exhibits long lithium stripping/plating stability for ≈2500 h with a lithium-ion transference number of 0.68. A lean-electrolyte lithium-sulfur full cell with a low electrolyte-to-sulfur ratio of 6 µL mg-1 is constructed with the designed high-loading polysulfide cathode and the thin lithium anode. The integration of all the critical cell-design parameters endows the lithium-sulfur full cell with a low negative-to-positive capacity ratio of 2.4, while exhibiting stable cyclability with an initial discharge capacity of 550 mAh g-1 and 60% capacity retention after 200 cycles.

Electrochemically Stable Rechargeable Lithium-Sulfur Batteries Equipped with an Electrospun Polyacrylonitrile Nanofiber Film.

The high theoretical charge-storage capacity and energy density of lithium-sulfur batteries make them a promising next-generation energy-storage system. However, liquid polysulfides are highly soluble in the electrolytes used in lithium-sulfur batteries, which results in irreversible loss of their active materials and rapid capacity degradation. In this study, we adopt the widely applied electrospinning method to fabricate an electrospun polyacrylonitrile film containing non-nanoporous fibers bearing continuous electrolyte tunnels and demonstrate that this serves as an effective separator in lithium-sulfur batteries. This polyacrylonitrile film exhibits high mechanical strength and supports a stable lithium stripping and plating reaction that persists for 1000 h, thereby protecting a lithium-metal electrode. The polyacrylonitrile film also enables a polysulfide cathode to attain high sulfur loadings (4-16 mg cm-2) and superior performance from C/20 to 1C with a long cycle life (200 cycles). The high reaction capability and stability of the polysulfide cathode result from the high polysulfide retention and smooth lithium-ion diffusion of the polyacrylonitrile film, which endows the lithium-sulfur cells with high areal capacities (7.0-8.6 mA·h cm-2) and energy densities (14.7-18.1 mW·h cm-2).

High Entropy Oxide (CrMnFeNiMg)3 O4 with Large Compositional Space Shows Long-Term Stability as Cathode in Lithium-Sulfur Batteries.

The repeated formation and irreversible diffusion of liquid-state lithium polysulfides (LiPSs) are the primary challenges in the development of high-energy-density lithium-sulfur battery (LSB). An effective strategy to alleviate the resulting polysulfide loss is critical for the stability of LSBs. In this regard, high entropy oxides (HEOs) appear as a promising additive for the adsorption and conversion of LiPSs owing to the diverse active sites, offering unparalleled synergistic effects. Herein, we have developed a (CrMnFeNiMg)3 O4 HEO as a functional polysulfide trapper in LSB cathode. The adsorption of LiPSs by the metal species (i. e., Cr, Mn, Fe, Ni, and Mg) in the HEO takes place through two different paths and leads to enhanced electrochemical stability. We demonstrate that the optimal sulfur cathode with the (CrMnFeNiMg)3 O4 HEO attains a high peak and reversible discharge capacities of 857 mAh g-1 and 552 mAh g-1 , respectively, at a cycling rate of C/10, a long cycle life of 300 cycles, and a high rate performance at the cycling rates from C/10 to C/2.

Structural and Surfacial Modification of Carbon Nanofoam as an Interlayer for Electrochemically Stable Lithium-Sulfur Cells.

Electrochemical lithium-sulfur batteries engage the attention of researchers due to their high-capacity sulfur cathodes, which meet the increasing energy-density needs of next-generation energy-storage systems. We present here the design, modification, and investigation of a carbon nanofoam as the interlayer in a lithium-sulfur cell to enable its high-loading sulfur cathode to attain high electrochemical utilization, efficiency, and stability. The carbon-nanofoam interlayer features a porous and tortuous carbon network that accelerates the charge transfer while decelerating the polysulfide diffusion. The improved cell demonstrates a high electrochemical utilization of over 80% and an enhanced stability of 200 cycles. With such a high-performance cell configuration, we investigate how the battery chemistry is affected by an additional polysulfide-trapping MoS2 layer and an additional electron-transferring graphene layer on the interlayer. Our results confirm that the cell-configuration modification brings major benefits to the development of a high-loading sulfur cathode for excellent electrochemical performances. We further demonstrate a high-loading cathode with the carbon-nanofoam interlayer, which attains a high sulfur loading of 8 mg cm-2, an excellent areal capacity of 8.7 mAh cm-2, and a superior energy density of 18.7 mWh cm-2 at a low electrolyte-to-sulfur ratio of 10 µL mg-1.

A Li2S-Based Catholyte/Solid-State-Electrolyte Composite for Electrochemically Stable Lithium-Sulfur Batteries.

Li2S, which features a high theoretical capacity of 1,166 mA·h g-1, is an attractive cathode material for developing high-energy-density lithium-sulfur batteries. However, pristine Li2S requires a high activation voltage of 4.0 V, which degrades both the electrolyte and electrode, leading to poor cycling performance. In an effort to reduce the activation overpotential, in this study, we investigate the use of P2S5 in an advanced Li2S-P2S5 catholyte and demonstrate a new synthetic approach that enables facile and low-temperature processing. Our findings show the P2S5 additive generates two thiophosphates with high ionic conductivities in the catholyte, which improve the activation efficiency and the electrochemical utilization. To further improve this advanced catholyte design, we also investigate two modified Li2S-P2S5 catholytes based on carbon black (to strengthen the conductivity) and dilute polysulfide (Li2S6; to amplify the reaction activity). Our analysis indicates that the optimal Li2S-P2S5-Li2S6 catholyte attains high ionic conductivity and strong reaction kinetics, achieving a high charge-storage capacity of 700 mA·h g-1 with a long-term cyclability of 200 cycles.

Advanced Current Collectors with Carbon Nanofoams for Electrochemically Stable Lithium-Sulfur Cells.

An inexpensive sulfur cathode with the highest possible charge storage capacity is attractive for the design of lithium-ion batteries with a high energy density and low cost. To promote existing lithium-sulfur battery technologies in the current energy storage market, it is critical to increase the electrochemical stability of the conversion-type sulfur cathode. Here, we present the adoption of a carbon nanofoam as an advanced current collector for the lithium-sulfur battery cathode. The carbon nanofoam has a conductive and tortuous network, which improves the conductivity of the sulfur cathode and reduces the loss of active material. The carbon nanofoam cathode thus enables the development of a high-loading sulfur cathode (4.8 mg cm-2) with a high discharge capacity that approaches 500 mA·h g-1 at the C/10 rate and an excellent cycle stability that achieves 90% capacity retention over 100 cycles. After adopting such an optimal cathode configuration, we superficially coat the carbon nanofoam with graphene and molybdenum disulfide (MoS2) to amplify the fast charge transfer and strong polysulfide-trapping capabilities, respectively. The highest charge storage capacity realized by the graphene-coated carbon nanofoam is 672 mA·h g-1 at the C/10 rate. The MoS2-coated carbon nanofoam features high electrochemical utilization attaining the high discharge capacity of 633 mA·h g-1 at the C/10 rate and stable cyclability featuring a capacity retention approaching 90%.

Nanoporosity of Carbon-Sulfur Nanocomposites toward the Lithium-Sulfur Battery Electrochemistry.

An ideal high-loading carbon-sulfur nanocomposite would enable high-energy-density lithium-sulfur batteries to show high electrochemical utilization, stability, and rate capability. Therefore, in this paper, we investigate the effects of the nanoporosity of various porous conductive carbon substrates (e.g., nonporous, microporous, micro/mesoporous, and macroporous carbons) on the electrochemical characteristics and cell performances of the resulting high-loading carbon-sulfur composite cathodes. The comparison analysis of this work demonstrates the importance of having high microporosity in the sulfur cathode substrate. The high-loading microporous carbon-sulfur cathode attains a high sulfur loading of 4 mg cm-2 and sulfur content of 80 wt% at a low electrolyte-to-sulfur ratio of 10 µL mg-1. The lithium-sulfur cell with the microporous carbon-sulfur cathode demonstrates excellent electrochemical performances, attaining a high discharge capacity approaching 1100 mA∙h g-1, a high-capacity retention of 75% after 100 cycles, and superior high-rate capability of C/20-C/3 with excellent reversibility.

A Poly(ethylene oxide)/Lithium bis(trifluoromethanesulfonyl)imide-Coated Polypropylene Membrane for a High-Loading Lithium-Sulfur Battery.

In lithium-sulfur cells, the dissolution and relocation of the liquid-state active material (polysulfides) lead to fast capacity fading and low Coulombic efficiency, resulting in poor long-term electrochemical stability. To solve this problem, we synthesize a composite using a gel polymer electrolyte and a separator as a functional membrane, coated with a layer of poly(ethylene oxide) (PEO) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). The PEO/LiTFSI-coated polypropylene membrane slows the diffusion of polysulfides and stabilizes the liquid-state active material within the cathode region of the cell, while allowing smooth lithium-ion transfer. The lithium-sulfur cells with the developed membrane demonstrate a high charge-storage capacity of 1212 mA∙h g-1, 981 mA∙h g-1, and 637 mA∙h g-1 at high sulfur loadings of 2 mg cm-2, 4 mg cm-2, and 6 mg cm-2, respectively, and maintains a high reversible capacity of 534 mA∙h g-1 after 200 cycles, proving its ability to block the irreversible diffusion of polysulfides and to maintain the stabilized polysulfides as the catholyte for improved electrochemical utilization and stability. As a comparison, reference and control cells fabricated using a PEO-coated polypropylene membrane and a regular separator, respectively, show a poor capacity of 662 mA∙h g-1 and a short cycle life of 50 cycles.

Lean-electrolyte lithium-sulfur electrochemical cells with high-loading carbon nanotube/nanofiber-polysulfide cathodes.

A carbon nanotube/nanofiber (CNT/CNF) composite is applied as a cathode substrate to develop a high-loading polysulfide cathode (8.64 mg cm-2, 68 wt% sulfur). The high-loading CNT/CNF-polysulfide cathode demonstrates high energy densities (11.4-15.7 mW h cm-2) and long-term cyclability (200 cycles) with low electrolyte-to-sulfur (E/S) ratios of 4-7 µL mg-1.

Module-Designed Carbon-Coated Separators for High-Loading, High-Sulfur-Utilization Cathodes in Lithium-Sulfur Batteries.

Lithium-sulfur batteries have great potential as next-generation energy-storage devices because of their high theoretical charge-storage capacity and the low cost of the sulfur cathode. To accelerate the development of lithium-sulfur technology, it is necessary to address the intrinsic material and extrinsic technological challenges brought about by the insulating active solid-state materials and the soluble active liquid-state materials. Herein, we report a systematic investigation of module-designed carbon-coated separators, where the carbon coating layer on the polypropylene membrane decreases the irreversible loss of dissolved polysulfides and increases the reaction kinetics of the high-loading sulfur cathode. Eight different conductive carbon coatings were considered to investigate how the materials' characteristics contribute to the lithium-sulfur cell's cathode performance. The cell with a nonporous-carbon-coated separator delivered an optimized peak capacity of 1112 mA∙h g-1 at a cycling rate of C/10 and retained a high reversible capacity of 710 mA∙h g-1 after 200 cycles under lean-electrolyte conditions. Moreover, we demonstrate the practical high specific capacity of the cathode and its commercial potential, achieving high sulfur loading and content of 4.0 mg cm-2 and 70 wt%, respectively, and attaining high areal and gravimetric capacities of 4.45 mA∙h cm-2 and 778 mA∙h g-1, respectively.

Current Status and Future Prospects of Metal-Sulfur Batteries.

Lithium-sulfur batteries are a major focus of academic and industrial energy-storage research due to their high theoretical energy density and the use of low-cost materials. The high energy density results from the conversion mechanism that lithium-sulfur cells utilize. The sulfur cathode, being naturally abundant and environmentally friendly, makes lithium-sulfur batteries a potential next-generation energy-storage technology. The current state of the research indicates that lithium-sulfur cells are now at the point of transitioning from laboratory-scale devices to a more practical energy-storage application. Based on similar electrochemical conversion reactions, the low-cost sulfur cathode can be coupled with a wide range of metallic anodes, such as sodium, potassium, magnesium, calcium, and aluminum. These new "metal-sulfur" systems exhibit great potential in either lowering the production cost or producing high energy density. Inspired by the rapid development of lithium-sulfur batteries and the prospect of metal-sulfur cells, here, over 450 research articles are summarized to analyze the research progress and explore the electrochemical characteristics, cell-assembly parameters, cell-testing conditions, and materials design. In addition to highlighting the current research progress, the possible future areas of research which are needed to bring conversion-type lithium-sulfur and other metal-sulfur batteries into the market are also discussed.

Bifunctional Binder with Nucleophilic Lithium Polysulfide Immobilization Ability for High-Loading, High-Thickness Cathodes in Lithium-Sulfur Batteries.

Lithium-sulfur batteries remain a promising next-generation renewable energy storage device due to their high theoretical energy density over the current commercial lithium-ion battery technology. However, to have any practical viability toward reaching the theoretical value, high-loading cathodes with sufficient sulfur content and specifically the effect of nonconductive binders must be investigated. We consider the limitations of conventional binders for high-loading, high-thickness cathodes by integrating a bifunctional binder with a linear polyethylene chain and maleate-capped ends. The linear polymer allows for flexibility within the high-loading cathode whereas the maleate ends improve the polysulfide trapping ability with carbon-sulfur binding. With the strong polysulfide immobilization ability due to the nucleophilic binding, the binder achieves high sulfur loadings of 12 mg cm-2 with a high sulfur content of 80 wt %. The work serves as a proof of concept for exploring the incorporation of polymeric materials into sulfur cathodes to realize practical viability.

Pyrrolic-Type Nitrogen-Doped Hierarchical Macro/Mesoporous Carbon as a Bifunctional Host for High-Performance Thick Cathodes for Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries are highly considered as a next-generation energy storage device due to their high theoretical energy density. For practical viability, reasonable active-material loading of >4.0 mg cm-2 must be employed, at a cost to the intrinsic instability of sulfur cathodes. The incursion of lithium polysulfides (LiPS) at higher sulfur loadings results in low active material utilization and poor cell cycling capability. The use of high-surface-area hierarchical macro/mesoporous inverse opal (IOP) carbons to investigate the effects of pore volume and surface area on the electrochemical stability of high-loading, high-thickness cathodes for Li-S batteries is presented here. The IOP carbons are additionally doped with pyrrolic-type nitrogen groups (N-IOP) to act as a polar polysulfide mediator and enhance the active-material reutilization. With a high sulfur loading of 6.0 mg cm-2 , the Li-S cells assembled with IOP and N-IOP carbons are able to attain a high specific capacity of, respectively, 1242 and 1162 mA h g-1 . The N-IOP enables the Li-S cells to demonstrate good electrochemical performance over 300 cycles.

Designing Lithium-Sulfur Batteries with High-Loading Cathodes at a Lean Electrolyte Condition.

Developing lithium-sulfur cells with a high-loading cathode at a lean-electrolyte condition is the key to bringing the lithium-sulfur technology into the energy-storage market. However, it has proven to be extremely challenging to develop a cell that simultaneously satisfies the abovementioned metrics while also displaying high electrochemical efficiency and stability. Here, we present a concept of constructing a conductive cathode substrate with a low surface area and optimized nanoporosity (i.e., limited micropores in the porous matrix) that enables achieving a high sulfur loading of 13 mg cm-2 and a high sulfur content of 75 wt % with an extremely low electrolyte/sulfur ratio of just 4.0 µL mg-1. The high-loading nanocomposite cathodes demonstrate high-areal capacities of 9.3 mA h cm-2, high energy densities of 18.6 mW h cm-2, and superior cyclability with excellent capacity retention of 85% after 200 cycles. These values are higher than the benchmarks set up for developing future commercial lithium-sulfur cells (i.e., areal capacity of >2-4 mA h cm-2, energy density of >8-13 mW h cm-2, and a long cycle life of 200 cycles with a capacity retention of 80%). The cathode design further exhibits high-rate capability from C/20 to 1 C rates and great potential to attain ultrahigh sulfur loading and a content of 17 mg cm-2 and 80 wt %. The key nanostructural feature that enables realizing fast-charge transport is the low surface area and limited microporosity that avoid the fast consumption of the electrolyte during cell cycling.

A Facile, Low-Cost Hot-Pressing Process for Fabricating Lithium-Sulfur Cells with Stable Dynamic and Static Electrochemistry.

Lithium-sulfur batteries are among the most promising low-cost, high-energy-density storage devices. However, the inability to host a sufficient amount of sulfur in the cathode while maintaining good electrochemical stability under a lean electrolyte condition has limited the progress. The main cause of these challenges is the sensitivity of the sulfur cathode to the cell-design parameters (i.e., the amount of sulfur and electrolyte) and the experimental testing conditions (i.e., cycling rates and analysis duration). Here, a hot-pressing method is presented that effectively encapsulates a high amount of sulfur in the cathode within only 5 s, resulting in high sulfur loading and content of, respectively, 10 mg cm-2 and 65 wt%. The hot-pressed sulfur (HPS) cathodes exhibit superior dynamic and static electrochemical performance under a broad cycling-rate (C/20-1C rates) and low electrolyte/sulfur ratio (6 µL mg-1 ) conditions. The dynamic cell stability is demonstrated by high gravimetric and areal capacities of, respectively, 415-730 mAh g-1 and 7-12 mAh cm-2 at C/20-1C rates with a high capacity retention of over 70% after 200 cycles. The static cell stability is demonstrated by excellent shelf life with low self-discharge and stable cycle life on storing for over one year.

Long-Life Lithium-Sulfur Batteries with a Bifunctional Cathode Substrate Configured with Boron Carbide Nanowires.

Developing high-energy-density lithium-sulfur (Li-S) batteries relies on the design of electrode substrates that can host a high sulfur loading and still attain high electrochemical utilization. Herein, a new bifunctional cathode substrate configured with boron-carbide nanowires in situ grown on carbon nanofibers (B4 C@CNF) is established through a facile catalyst-assisted process. The B4 C nanowires acting as chemical-anchoring centers provide strong polysulfide adsorptivity, as validated by experimental data and first-principle calculations. Meanwhile, the catalytic effect of B4 C also accelerates the redox kinetics of polysulfide conversion, contributing to enhanced rate capability. As a result, a remarkable capacity retention of 80% after 500 cycles as well as stable cyclability at 4C rate is accomplished with the cells employing B4 C@CNF as a cathode substrate for sulfur. Moreover, the B4 C@CNF substrate enables the cathode to achieve both high sulfur content (70 wt%) and sulfur loading (10.3 mg cm-2 ), delivering a superb areal capacity of 9 mAh cm-2 . Additionally, Li-S pouch cells fabricated with the B4 C@CNF substrate are able to host a high sulfur mass of 200 mg per cathode and deliver a high discharge capacity of 125 mAh after 50 cycles.

Thin-Layered Molybdenum Disulfide Nanoparticles as an Effective Polysulfide Mediator in Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries are attractive as sulfur offers an order of magnitude higher charge-storage capacity than the currently used insertion-compound cathodes. However, their practical viability is hampered by low electrochemical stability and efficiency, which results from severe polysulfide (LiPS) shuttling during cycling. We present here thin-layered MoS2 nanoparticles (MoS2-NPs) synthesized through a one-pot method and coated onto a commercial polymeric separator (as MoS2-NP-coated separator) as an effective LiPS mediator, facilitated by the nanodimension, polar interactions, and the better edge-binding sites of the MoS2-NPs. The resulting MoS2-NPs have an interlayer spacing of 0.55 nm and are stacked with a few layers. At a sulfur loading of 4.0 mg cm-2, the Li-S cell with a MoS2-NP-coated separator attains a peak discharge capacity of 983 mA h g-1, improving the electrochemical utilization of sulfur. The cell is able to maintain a high capacity of 525 mA h g-1 after 150 cycles at a C/5 rate. The MoS2-NPs are able to effectively anchor the LiPS species to their large S2- anions, enhancing the redox accessibility of sulfur cathodes and enabling better capacity retention.