Sulfur Cathode Research Articles

Enhanced Performance of Lithium-Sulfur Batteries Using Construction Wastes: A Sustainable Approach to High-Loading Sulfur Cathodes.

Advancing lithium-sulfur battery technology requires addressing both extrinsic cell-fabrication and intrinsic material challenges to improve efficiency, cyclability, and environmental sustainability. A key challenge is the low conductivity of sulfur cathodes, which is typically managed by incorporating conductive carbon materials. These materials enhance the performance of sulfur cathodes by facilitating high sulfur loading and improving polysulfide retention. In line with green chemistry principles and circular economy concepts, this study explores the use of recycled materials-specifically recycled quartz and board-as substrates for graphene coatings in lithium-sulfur cells. Recycled quartz bricks and blocks, predominantly SiO2, and recycled shelf boards, rich in Al2O3, are successfully coated with graphene, which significantly improves polysulfide adsorption and overall battery performance. The graphene-coated quartz exhibits high sulfur loading (8 mg cm-2), exceptional charge-storage capacity (1,114 mA·h g-1), and long cycle stability (200 cycles) with an energy density of 19 mW·h cm-2. This approach enhances the electrochemical performance of the lithium-sulfur cells and also aligns with sustainability goals by repurposing waste materials and minimizing environmental impact. This novel methodology demonstrates that integrating recycled materials can effectively address key challenges in lithium-sulfur battery technology, advancing both performance and environmental sustainability.

Balancing high graphitization and porous structure in N-doped carbon lamella for effective sulfur host of Li[sbnd]S battery

Porous carbon synchronously with high conductivity and abundant porous structure is considered to be an effective sulfur host material for boosting the lithium-storage property in battery fields. Herein, a natural silk cocoon derived in-situ N-doping porous carbon lamella with ultrahigh graphitization degree is prepared by a facile synchronous carbonization and catalysis using the bimetallic mixed salts of FeCl3 and ZnCl2. The pore structure and graphitization degree are easily regulated by changing carbonization temperature to balance the synergistic adsorption and conversion actions toward the polysulfides adhered to porous carbon lamellar. When the carbon lamellar is used to design sulfur cathode, the abundant porous structure not only encapsulates active sulfur, but also facilitates electrolyte infiltration. The shuttle effect of polysulfides can be restrained by the synergistic adsorption of porous structure and N-doping. Especially, the ultrahigh graphitized carbon lamellas provide an excellent conductive network for the favorable redox conversion of polysulfide species during charge/discharge. Owing to the structure merits of the porous carbon lamella prepared at 1000 °C, the corresponding carbon/sulfur composite cathode delivers a first discharge capacity of 807.7 mAh g−1 at 0.2C. Even at a current rate of 1C, the stable long cycling performance of 1000 cycles is still maintained. This high graphitized porous carbon materials will provide potential application in other energy-storage fields.

In Situ Synthesis of CoMoO4 Microsphere@rGO as a Matrix for High-Performance Li-S Batteries at Room and Low Temperatures

Lithium–sulfur batteries (Li-S batteries) have attracted wide attention due to their high theoretical energy density and the low cost of sulfur cathode material. However, the poor conductivity of the sulfur cathode, the polysulfide shuttle effect, and the slow redox kinetics severely affect their cycling performance and Coulombic efficiencies, especially under low-temperature conditions, where these effects are more exacerbated. To address these issues, this study designs and synthesizes a microspherical cobalt molybdate@reduced graphene oxide (CoMoO4@rGO) composite material as the cathode material for Li-S batteries. By growing CoMoO4 nanoparticles on the rGO surface, the composite material not only provides a good conductive network but also significantly enhances the adsorption capacity to polysulfides, effectively suppressing the shuttle effect. After 100 cycles at room temperature with a current density of 1 C, the reversible specific capacity of the battery stabilizes at 805 mAh g−1. Notably, at −20 °C, the S/CoMoO4@rGO composite achieves a reversible specific capacity of 840 mAh g−1. This study demonstrates that the CoMoO4@rGO composite has significant advantages in suppressing polysulfide diffusion and expanding the working temperature range of Li-S batteries, showing great potential for applications in next-generation high-performance Li-S batteries.

Coordinatively Unsaturated Co Single-Atom Catalysts Enhance the Performance of Lithium-Sulfur Batteries by Triggering Strong d-p Orbital Hybridization.

The catalytic activities displayed by single-atom catalysts (SACs) depend on the coordination structure. SACs supported on carbon materials often adopt saturated coordination structures with uneven distributions because they require high-temperature conditions during synthesis. Herein, bisnitrogen-chelated Co SACs that are coordinatively unsaturated are prepared by integrating a Co complex into a conjugated microporous polymer (CMP-CoN2). Compared with saturated analogues, i.e., tetranitrogen-chelated Co SACs (denoted as CMP-CoN4), CMP-CoN2 exhibits higher electrocatalytic activity in polysulfide conversions due to an enhanced hybridization between the 3d orbitals of the Co atoms and the 3p orbitals of the S atoms in the polysulfide. As a result, sulfur cathodes prepared with CoN2 deliver outstanding performance metrics, including a high specific capacity (1393 mA h g-1 at 0.1 C), a superior rate capacity (673.2 mA h g-1 at 6 C), and a low capacity decay rate (of only 0.045% per cycle at 2 C over 1000 cycles). They also outperform sulfur cathodes that contain CMP-CoN4 or CMPs that are devoid of Co SACs. This work reveals how the catalytic activity displayed by SACs is affected by their coordination structures, and the rules that underpin the structure-activity relationship may be extended to designing electrocatalysts for use in other applications.

Ab Initio Simulation of Raman Fingerprints of Sulfur/Carbon Copolymer Cathodes During Discharge of Li-S Batteries.

Sulfur/carbon copolymers have emerged as promising alternatives for conventional crystalline sulfur cathodes for lithium-sulfur batteries. Among these, sulfur--n--1,3--diisopropenylbenzene (S/DIB) copolymers, which present a 3D network of DIB molecules interconnected via sulfur chains, have particularly shown a good performance and, therefore, have been under intensive experimental and theoretical investigations. However, their structural complexity and flexibility have hindered a clear understanding of their structural evolution during redox reactions at an atomistic level. Here, by performing state-of-the-art ab initiomolecular dynamics-based Raman spectroscopy simulations, we investigate the spectral fingerprints of S/DIB copolymers arising from local structures during consecutive reactions with lithium. We discuss Raman spectral changes in particular frequency ranges which are common in S/DIB copolymers having shortand those consisting of longer sulfur chains. We also highlight those spectroscopic fingerprints specific to local S/DIB structures containing only short or long sulfur chains. This could help distinguish them experimentally during discharge. Our theoretically predicted results are in a good agreement with experimental Raman measurements on cells at different discharge stages. This work representsan attempt to compute Raman fingerprints ofcopolymer cathodes during battery operationincluding quantum-chemical and finite-temperature effects, and provides a guideline for Raman spectral changes of arbitrary electrodes during discharge.

Review on polymer electrolytes for lithium‐sulfurized polyacrylonitrile batteries

AbstractLithium‐sulfur (Li‐S) batteries are deemed as the next generation of energy storage devices due to high theoretical specific capacity (1675 mAh g−1) and energy density (2600 Wh kg−1). However, the commercial application has always been constrained by lithium polysulfide (LiPSs) shuttling effects and still has a long way to go. Sulfurized polyacrylonitrile (SPAN) is a promising alternative candidate to replace traditional sulfur cathode and is conducive to eliminating LiPSs by realizing “solid‐solid” direct conversion in conventional carbonate electrolytes. However, an over 25% irreversible capacity loss is exhibited inevitably in the first discharge process, the inherent structure of SPAN and the related reaction mechanism remain unclear. In this review, the structure characteristics and electrochemical behaviors of SPAN are summarized for better interpreting current knowledge and favoring the design of high performance materials. In the past few decades, many problems in traditional Li‐S batteries have been solved by improving electrolytes. Polymer electrolytes (PEs) have been widely used due to structural designability, multi‐functionality, exceptional chemical stability, and excellent processability. Surprisingly, the relevant researches on PEs compatible with SPAN remains limited currently. Therefore, the recent modification strategies of gel polymer electrolytes and solid polymer electrolytes in Li‐SPAN batteries are introduced in terms of Li+ transfer and interface engineering, the design principles are concluded, the specific challenges encountered by polymer‐based electrolytes are summarized and the instructive directions for future research on PEs are demonstrated, facilitating the commercialization of Li‐SPAN batteries.

Optimizing Aqueous Zinc-Sulfur Battery Performance via Regulating Acetonitrile Co-Solvents and Carbon Nanotube Carriers.

Rechargeable aqueous zinc-sulfur batteries (AZSBs) are gaining attention due to their high energy density, ultra-stable discharge platform, and safety. However, poor liquid/solid reaction processes at the anode and cathode reduce reaction kinetics, and the severe dissolution of polysulfides causes shuttle effects during discharge/charge cycles, hindering practical applications. Improving performance requires optimizing both the cathode and electrolyte. Herein, we design an organic-inorganic hybrid electrolyte (zinc trifluoromethanesulfonate and trace iodine monomer dissolved in an acetonitrile/water co-solvent (AN-X)) and a partially exfoliated multi-walled carbon nanotube (PECNT) hosted sulfur (S@PECNTs) cathode for AZSBs. The sulfur is highly dispersed along the PECNTs with appropriate wettability at the electrode/electrolyte interface using AN-3 as the electrolyte. Meanwhile, this electrolyte inhibits hydrogen evolution at negative potentials and promotes uniform Zn ion stripping/plating. Expressively, the AN-3-based AZSB exhibits a high discharge capacity of 1370 mAh g-1 with excellent Coulombic efficiency (79.9%), outstanding rate capability, and cycling performance. These improvements are attributed to the synergistic effect between the S@PECNTs and the AN-3 electrolyte, which reduces Rct to enhance reaction kinetics and blocks the dissolution and shuttle effect of polysulfides, ensuring a reversible reaction between zinc and sulfur.

Bi-Functional Materials for Sulfur Cathode and Lithium Metal Anode of Lithium-Sulfur Batteries: Status and Challenges.

Over the past decade, the most fundamental challenges faced by the development of lithium-sulfur batteries (LSBs) and their effective solutions have been extensively studied. To further transfer LSBs from the research phase into the industrial phase, strategies to improve the performance of LSBs under practical conditions are comprehensively investigated. These strategies can simultaneously optimize the sulfur cathode and Li-metal anode to account for their interactions under practical conditions, without involving complex preparation or costly processes. Therefore, "two-in-one" strategies, which meet the above requirements because they can simultaneously improve the performance of both electrodes, are widely investigated. However, their development faces several challenges, such as confused design ideas for bi-functional sites and simplex evaluation methods (i. e. evaluating strategies based on their bi-functionality only). To date, as few reviews have focused on these challenges, the modification direction of these strategies is indistinct, hindering further developments in the field. In this review, the advances achieved in "two-in-one" strategies and categorizing them based on their design ideas are summarized. These strategies are then comprehensively evaluated in terms of bi-functionality, large-scale preparation, impact on energy density, and economy. Finally, the challenges still faced by these strategies and some research prospects are discussed.

Preparation of TiO2 nanoparticles decorated porous carbon via a pseudo co-templating strategy and their application as substrates for high performance cathode of Li[sbnd]S batteries

Lithium‑sulfur batteries (LSBs) with a high theoretical specific capacity are considered as one of the most promising energy storage devices for next-generation. However, issues such as the insulation of pristine sulfur, the shuttle effect of polysulfides (LiPSs), and the volume change of sulfur cathode during cycling hinder their commercial applications. In this work, composite microspheres of TiO2@p-C consisting of porous carbon decorated with TiO2 nanoparticles, have been designed and synthesized aiming to confine and trap the polysulfides inside the porous substrates and to improve the kinetics of the electrochemical reaction therein. TiO2 particles with size of a few nanometers are prepared by a tetraethyl ammonium hydroxide assisted sol-gel method. Composite microspheres of TiO2@p-C are created through spray drying technique using chitosan as carbon source, and nanoparticles of SiO2 with TiO2 as co-template while selectively etching of the former. The confinement effects via the pores in the TiO2@p-C microspheres and the affinity between the polar TiO2 moieties and the polysulfide species work synergistically, alleviating the effusion of the polysulfides and promoting the conversion reaction of them as well. As a result, the shuttle effect of polysulfides can be inhibited obviously. Significantly, the S@TiO2@p-C-2 composite cathode exhibits excellent cyclic performance of 1263 mAh g−1 at 0.2C and maintains still a discharge capacity of 809 mAh g−1 after 100 charge and discharge cycles. At a current density of 2C, it still delivers an outstanding specific capacity of 772 mAh g−1. In the case of high sulfur load up to 90 wt%, the discharge capacity of S@TiO2@p-C-2 composite electrode could still maintain at 469.5 mAh g−1 after 100 cycles under current density of 0.2C.

Insight into the Impact of Electrolyte on Passivation of Lithium–Sulfur Cathodes

AbstractOne of the remaining challenges for lithium–sulfur batteries toward practical application is early cathode passivation by the insulating discharge product: Li2S. To understand how to best mitigate passivation and minimize related performance loss, a kinetic Monte–Carlo model for Li2S crystal growth from solution is developed. The key mechanisms behind the strongly different natures of Li2S layer growth, structure, and morphology for salts with different (DN) are revealed. LiTFSI electrolyte in dimethyl ether leads to lateral Li2S growth on carbon and fast passivation because it increases the Li2S precipitation‐to‐dissolution probability on carbon relative to Li2S. In contrast, LiBr electrolyte has a higher DN and yields a particle‐like structure due to a significantly higher precipitation‐to‐dissolution probability on Li2S compared to carbon. The resulting large number of Li2S sites further favors particle growth, leading to low passivation. This study is able to identify the key parameters of the electrolyte and substrate material to tune Li2S morphology and growth to pave the way for optimized performance.

Bimetallic NiCo@C with a Hollow Sea Urchin Structure Enables Li-S Batteries to Hasten the Reaction Kinetics and Effectively Inhibit the Shuttling of Polysulfides.

The "shuttle effect" and several issues related to it are seen as "obstacles" to the study and development of lithium-sulfur batteries (LSBs). This work aims at finding how to fully expose bimetallic sites and quicken the battery reaction kinetics. Here, a bimetallic NiCo-MOF and its derivative NiCo@C with a hollow sea urchin structure are produced. The obtained NiCo@C possesses a micromesoporous structure and fully disclosed bimetallic active sites because of its distinctive structure. The experimental findings demonstrate that fully exposed bimetallic active sites take on chemical adsorbents and collaborate with micromesopores as physical constraints to effectively suppress the "shuttle effect". Furthermore, the hollow sea urchin structure of NiCo@C enables a highly conductive grid, which provides channels to facilitate the movement of solvated Li+. Thanks to these advantages, the NiCo@C-based sulfur cathode offers a high initial discharge specific capacity of 924.41 mAh g-1 at 0.1 C and sustains 390.35 mAh g-1 discharge specific capacity after 100 cycles. The quick transfer of solvated lithium ions (DLi+ = 1.81 × 10-8 cm2 s-1) enables the battery to still contribute a discharge specific capacity of 367.54 mAh g-1 at 1 C. This work provides a new understanding for the structural design of positive electrodes in LSBs.

Adsorption and Catalysis Effects of LaMnO3 Nanosheets for High‐Performance Li–S Batteries

In this article, an effective redox regulation strategy of Li–S batteries is illustrated by introducing a unique petal‐like LaMnO3 nanosheet (LMO‐NS) into the sulfur cathode. It is found that the LMO‐NS with abundant active sites offers strong chemical affinity toward the sulfur species, which play key roles in immobilizing the produced polysulfides during charge/discharge operation and then accelerating their redox conversion. Consequently, the Li–S reaction kinetics is remarkably boosted and the polysulfide shuttle is greatly alleviated owing to the adsorption‐catalysis effects of the LMO‐NS, which endows the composite cathode with increased reversible capacity and improved cycle and rate capability.

Cutting-Edge Progress in Aqueous Zn-S Batteries: Innovations in Cathodes, Electrolytes, and Mediators.

Rechargeable aqueous zinc-sulfur batteries (AZSBs) are emerging as prominent candidates for next-generation energy storage devices owing to their affordability, non-toxicity, environmental friendliness, non-flammability, and use of earth-abundant electrodes and aqueous electrolytes. However, AZSBs currently face challenges in achieving satisfied electrochemical performance due to slow kinetic reactions and limited stability. Therefore, further research and improvement efforts are crucial for advancing AZSBs technology. In this comprehensive review, it is delved into the primary mechanisms governing AZSBs, assess recent advancements in the field, and analyse pivotal modifications made to electrodes and electrolytes to enhance AZSBs performance. This includes the development of novel host materials for sulfur (S) cathodes, which are capable of supporting higher S loading capacities and the refinement of electrolyte compositions to improve ionic conductivity and stability. Moreover, the potential applications of AZSBs across various energy platforms and evaluate their market viability based on recent scholarly contributions is explored. By doing so, this review provides a visionary outlook on future research directions for AZSBs, driving continuous advancements in stable AZSBs technology and deepening the understanding of their charge-discharge dynamics. The insights presented in this review signify a significant step toward a sustainable energy future powered by renewable sources.

Engineering rare earth metal Ce-N coordination as catalyst for high redox kinetics in lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries are a key area of research in energy storage due to their high theoretical energy density, low cost, and environmental friendliness. However, the shuttle effect caused by lithium polysulfides (LiPSs) intermediates often results in poor cycling stability. Therefore, constructing rational cathode structures to achieve fast reaction kinetics in adsorbing and catalyzing LiPSs is the key to obtain high-performance Li-S batteries. Metallic single-atom catalysts (SACs), known for their 100 % atomic utilization rate and low cost, have demonstrated excellent catalytic activity and selectivity in the redox reactions of Li-S batteries, positioning them as one of the most promising catalysts in this field. Rare earth metallic SACs with versatile oxidation states, diverse coordination chemistry and environmentally friendly are rarely investigated in Li-S system. Herein, we fabricate a rare earth metal-based single-atom catalyst (CeSAs) supported on a three-dimensional porous N-doped carbon (3DCeSA-N-WS), and systematically study its performance in Li-S batteries. Benefitting from the atomic dispersion and versatile oxidation states (Ce3+/Ce4+), the 3DCeSA-N-WS demonstrates excellent performance in anchoring and catalyzing LiPSs, significantly enhancing the redox reaction kinetics. Consequently, the prepared sulfur cathode exhibits exceptional electrochemical performance, with a high initial specific discharge capacity of 1225 mAh g−1 at 0.2 C and a capacity retention of 76.1 % after 160 cycles. The assembled 100 mAh-level pouch cellmaintains a high specific discharge capacity of 877 mAh g−1 after 50 cycles at 0.5 C. This work provides new insights into the design of sulfur cathode catalysts, thereby contributing to the realization of high-performance Li-S batteries.

Operando Fabricated Quasi-Solid-State Electrolyte Hinders Polysulfide Shuttles in an Advanced Li-S Battery

Lithium-sulfur (Li-S) batteries are a promising option for energy storage due to their theoretical high energy density and the use of abundant, low-cost sulfur cathodes. Nevertheless, several obstacles remain, including the dissolution of lithium polysulfides (LiPS) into the electrolyte and a restricted operational temperature range. This manuscript presents a promising approach to addressing these challenges. The manuscript describes a straightforward and scalable in situ thermal polymerization method for synthesizing a quasi-solid-state electrolyte (QSE) by gelling pentaerythritol tetraacrylate (PETEA), azobisisobutyronitrile (AIBN), and a dual salt lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and lithium nitrate (LiNO3)-based liquid electrolyte. The resulting freestanding quasi-solid-state electrolyte (QSE) effectively inhibits the polysulfide shuttle effect across a wider temperature range of −25 °C to 45 °C. The electrolyte’s ability to prevent LiPS migration and cluster formation has been corroborated by scanning electron microscopy (SEM) and Raman spectroscopy analyses. The optimized QSE composition appears to act as a physical barrier, thereby significantly improving battery performance. Notably, the capacity retention has been demonstrated to reach 95% after 100 cycles at a 2C rate. Furthermore, the simple and scalable synthesis process paves the way for the potential commercialization of this technology.

Spatial structure design of interlayer for advanced lithium–sulfur batteries

The practical application of lithium-sulfur (Li–S) batteries has been hindered by the lithium polysulfide shuttle effect. An effective way to solve this problem is to utilize interlayer engineering to confine polysulfides and promote their catalytic conversion. From a spatial perspective, we designed a carbon nanofiber conductive layer (CNF, without Sn content, labeled as 0) and two Sn-doped carbon nanofiber catalytic layers (SCNF, with 10 wt% and 20 wt% Sn content, labeled as 1 and 2, respectively) with different contents of catalyst content, and verified an efficient interlayer structure by adjusting the order of preferential contact between the conductive layer and the catalytic layer with the sulfur cathode to form a hierarchical system for the inhibition and conversion of lithium polysulfide. Electrochemical measurements show that different spatial configurations have significant discrepancies on the electrochemical performance of Li–S batteries. Thus, the space configuration of 210 enables the Li–S battery to provide a specific capacity of up to 1088 mAh g−1 after 100 cycles at 0.2C. Even under the harsh conditions of high sulfur loading (5.6 mg cm−2) and lean electrolyte (E/S = 10 μL mg−1), the Li–S battery was able to cycle stably for 94 cycles at 0.2C with 87 % capacity retention. This study provides a novel spatial strategy for advancing the spatial design of high-performance Li–S batteries.

Building Li–S batteries with enhanced temperature adaptability via a redox-active COF-based barrier-trapping electrocatalyst

Covalent organic frameworks (COFs) are promising materials for mitigating polysulfide shuttling in lithium-sulfur (Li–S) batteries, but enhancing their ability to convert polysulfides across a wide temperature range remains a challenge. Herein, we introduce a redox-active COF (RaCOF) that functions as both a physical barrier and a kinetic enhancer to improve the temperature adaptability of Li–S batteries. The RaCOF constructed from redox-active anthraquinone units accelerates polysulfide conversion kinetics through reversible C=O/C-OLi transformations within a voltage range of 1.7 to 2.8 V (vs. Li+/Li), optimizing sulfur redox reactions in ether-based electrolytes. Unlike conventional COFs, RaCOF provides bidentate trapping of polysulfides, increasing binding energy and facilitating more effective polysulfide management. In-situ XRD and ToF-SIMS analyses confirm that RaCOF enhances polysulfide adsorption and promotes the transformation of lithium sulfide (Li2S), leading to better sulfur cathode reutilization. Consequently, RaCOF-modified Li–S batteries demonstrate low self-discharge (4.0% decay over a 7-day rest), excellent wide-temperature performance (stable from −10 to +60 °C), and high-rate cycling stability (94% capacity retention over 500 cycles at 5.0 C). This work offers valuable insights for designing COF structures aimed at achieving temperature-adaptive performance in rechargeable batteries.

Development and Optimization of Thin-Lithium-Metal Anodes with a Lithium Lanthanum Titanate Stabilization Coating for Enhancement of Lithium-Sulfur Battery Performance.

Lithium-ion batteries are dominating high-energy-density energy storage for 30 years. However, their development approaches theoretical limits, spurring the development of lithium-sulfur cells that achieve high energy densities through reversible electrochemical conversion reactions. Nevertheless, the commercialization of lithium-sulfur cells is hindered by practical challenges associated primarily with the use of thick-lithium anodes, low-loading sulfur cathodes, and high electrolyte-to-sulfur ratios, which prevent realization of the cells' full potential in terms of electrochemical and material performance. To solve these extrinsic and intrinsic problems, the effect of lithium-metal thickness on the electrochemical behavior of lithium-sulfur cells with high-loading sulfur cathodes in lean-electrolyte configurations is investigated. Specifically, lithium lanthanum titanate (LLTO), a solid electrolyte, is utilized to form an ionically/electronically conductive coating to stabilize lithium-metal anodes, thereby enhancing their lithium-ion pathways and interfacial charge transfer. Electrochemical analyses reveal that an LLTO coating significantly reduces excessive reactions between lithium metal and an electrolyte, thereby minimizing lithium consumption and electrolyte depletion. Further, LLTO-stabilized lithium anodes improve lithium-sulfur cell performance, and most importantly, allow the fabrication of thin-lithium, high-loading-sulfur cells that open a pathway toward high-energy-density batteries.

Scalable Li-Ion Battery with Metal/Metal Oxide Sulfur Cathode and Lithiated Silicon Oxide/Carbon Anode.

A Li-ion battery combines a cathode benefitting from Sn and MnO2 with high sulfur content, and a lithiated anode including fumed silica, few layer graphene (FLG) and amorphous carbon. This battery is considered a scalable version of the system based on lithium-sulfur (Li-S) conversion, since it exploits at the anode the Li-ion electrochemistry instead of Li-metal stripping/deposition. Sn and MnO2 are used as cathode additives to improve the electrochemical process, increase sulfur utilization, while mitigating the polysulfides loss typical of Li-S devices. The cathode demonstrates in half-cell a maximum capacity of ~1170 mAh gS -1, rate performance extended over 1 C, and retention of 250 cycles. The anode undergoes Li-(de)alloying with silicon, Li-(de)insertion into amorphous carbon, and Li-(de)intercalation through FLG, with capacity of 500 mAh g-1 in half-cell, completely retained over 400 cycles. The full-cells are assembled by combining a sulfur cathode with active material loading up to 3 mg cm-2 and lithiated version of the anode, achieved either using an electrochemical pathway or a chemical one. The cells deliver at C/5 initial capacity higher than 1000 mAh gS -1, retained for over ~40 % upon 400 cycles. The battery is considered a promising energy storage system for possible scaling-up in pouch or cylindrical cells.

Customized Nano‐Confinement Effects of Metal‐Organic Frameworks for High‐Performance Lithium‐Sulfur Batteries

Lithium‐sulfur batteries (LSBs) are considered one of the most promising next‐generation energy storage devices due to their significant theoretical energy density and high specific capacity of sulfur cathode. However, several critical challenges still must be addressed for practical application. The shuttle effect and sluggish redox kinetics severely impact their performance. Metal‐organic frameworks (MOFs) have garnered significant interest attributed to their high structural tunability. Their ability to nano‐confine lithium polysulfides (LiPSs) can be precisely controlled at the molecular level by regulating metal centers and organic ligands, thereby suppressing the shuttle effect and improving the electrochemical performance of LSBs. This review summarizes the nano‐confinement effects of MOFs in LSBs, and the discussion is divided into the selective confinement and nano‐confined adsorption by inert MOFs, as well as nano‐confined catalysis facilitated by catalytically active MOFs. Furthermore, the existing challenges and future prospects for application of MOFs in LSBs are proposed.