Lithium Sulfur Research Articles

Inverse vulcanized sulfur-styrene polymers as effective plasticizers for polystyrene

Inverse vulcanized polymers have demonstrated significant potential as alternatives to conventional petrochemical polymers in various applications, including environmental remediation, where they are used to absorb heavy metals and pollutants from water and soil, and energy devices, such as in the development of high-capacity lithium-sulfur batteries. Despite their promise in these areas, the full application scope of these sulfur-based polymers remains unexplored. There is substantial potential for their use in other fields, such as advanced material coatings, medical devices, and as additives to improve the properties of existing polymers, yet these possibilities have not been thoroughly investigated. This study presents a sulfur-based polymer, synthesized via the inverse vulcanization of sulfur and styrene and partially crosslinked with divinylbenzene, as a novel plasticizer for polystyrene (PS). This polymer blend was prepared using an internal mixer to replace conventional organic-based plasticizers. The selected system was designed to maximize miscibility. Both virgin and plasticized PS were injection molded for comprehensive characterization. Differential Scanning Calorimetry (DSC) confirmed the complete consumption of sulfur, revealing a significant reduction in the glass transition temperature of PS upon the addition of the sulfur-based plasticizer. Morphological analysis showed a homogeneous surface with uniform single-phase morphology, indicating full miscibility of the blend. Tensile tests demonstrated enhanced ductility and reduced stiffness in plasticized PS, with strain at maximum tensile strength and elongation at break increasing by 22.0 % and 28.1 %, respectively. The plasticizer also improved the toughness of PS by 25.2 %. Rheological assessments corroborated the plasticization effect and confirmed the blend's full miscibility. Contact angle measurements indicated increased hydrophilicity of the plasticized PS samples. This newly developed sulfur-based plasticizer proved to be highly effective for PS, showcasing competitive efficiency comparable to commercial plasticizers. This advancement paves the way for new applications in the expanding field of sulfur-based polymers.

Corrigendum to “A fresh perspective to synthesizing and designing carbon/sulfur composite cathodes using supercritical CO2 technology for advanced Li-S battery cathodes” [J. Alloy. Compd. 1008 (2024) 176691]

Corrigendum to “A fresh perspective to synthesizing and designing carbon/sulfur composite cathodes using supercritical CO2 technology for advanced Li-S battery cathodes” [J. Alloy. Compd. 1008 (2024) 176691]

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.

Challenges and Prospects of Electrolyte Design for Lithium‐Sulfurized Polyacrylonitrile Batteries

AbstractSulfurized polyacrylonitrile (SPAN) is regarded as a promising organic sulphur cathode material for lithium‐sulfur (Li−S) batteries. It undergoes a solid‐solid conversion without forming polysulfide intermediate phases, overcoming the poor electrochemical performance caused by the shuttle effect of elemental S cathodes. However, realizing this unique conversion mechanism requires employing appropriate electrolytes. Furthermore, the direct application of metallic Li as the anode unavoidable introduces a series of issues triggered by Li dendrites in Li‐SPAN batteries, such as low lifespan, short circuits, fire, etc. In this review, we endeavor to encapsulate recent advancements in electrolyte research, with a particular focus on the intrinsic relationship between the solvation structure of the electrolyte and the interfacial chemistry of the Li anode and SPAN electrode, aim to provide insights into the electrolytes design for high performance Li‐SPAN full batteries.

Copper-nickel MOF-coated electrospun polyacrylonitrile membranes for Li–S batteries: Mitigating the shuttle effect and enhancing stability

Cu–Ni MOF nanoparticles were synthesized as coating materials for lithium–sulfur battery membranes, and the performance of batteries employing Cu–Ni MOF/PAN (CNMP) electrospinning membranes were examined. The modified membrane efficiently suppresses the shuttle effect, leveraging the synergistic catalysis and adsorption capabilities of the Cu–Ni MOF nanoparticles. The modified membrane exhibited relatively high porosity and outstanding electrolyte absorption capacity. The CNMP membrane battery demonstrated a remarkable first-cycle discharge capacity of 1529 mA h g⁻¹. The battery maintained an exceptional discharge capacity with 85.2 % retention and a minimal capacity decay rate of just 0.074 % per cycle after 200 cycles at 0.5 C. The capacity retention of the modified membrane battery remained at 74.6 % even after 2000 cycles at 2 C. The excellent performance of the modified membrane battery was due to the physical entrapment and strong chemical adsorption of lithium polysulfides by Cu–Ni MOF nanoparticles, significantly preventing the shuttle effect and facilitating rapid oxidation–reduction kinetics based on strong catalytic conversion.

Solid‐State Electrolytes for Lithium Metal Batteries: State‐of‐the‐Art and Perspectives

AbstractThe use of all‐solid‐state lithium metal batteries (ASSLMBs) has garnered significant attention as a promising solution for advanced energy storage systems. By employing non‐flammable solid electrolytes in ASSLMBs, their safety profile is enhanced, and the use of lithium metal as the anode allows for higher energy density compared to traditional lithium‐ion batteries. To fully realize the potential of ASSLMBs, solid‐state electrolytes (SSEs) must meet several requirements. These include high ionic conductivity and Li+ transference number, smooth interfacial contact between SSEs and electrodes, low manufacturing cost, excellent electrochemical stability, and effective suppression of dendrite formation. This paper delves into the essential requirements of SSEs to enable the successful implementation of ASSLMBs. Additionally, the representative state‐of‐the‐art examples of SSEs developed in the past 5 years, showcasing the latest advancements in SSE materials and highlighting their unique properties are discussed. Finally, the paper provides an outlook on achieving balanced and improved SSEs for ASSLMBs, addressing failure mechanisms and solutions, highlighting critical challenges such as the reversibility of Li plating/stripping and thermal runaway, advanced characterization techniques, composite SSEs, computational studies, and potential and challenges of ASS lithium–sulfur and lithium–oxygen batteries. With this consideration, balanced and improved SSEs for ASSLMBs can be realized.

Challenges and Approaches to Designing High‐Energy Density Lithium‐Sulfur Pouch Cells

AbstractLithium‐sulfur (Li−S) batteries are of great interest as next‐generation energy storage devices in a wide variety of applications, due to their high specific capacity and the environmental abundance of sulfur. However, liquid electrolyte Li−S technology faces several challenges such as polysulfide shuttling, anode corrosion and sluggish cathode kinetics. Practical deployment of Li−S batteries requires evaluation in large‐format, high energy density pouch cells. Stringent operating conditions such as high sulfur loading and operating current, low electrolyte amount, and limited anode quantity are required for high energy density pouch cells, which further curtails the electrochemical performance and cycle life. This review aims to provide an understanding of the different failure mechanisms of large‐format Li−S pouch cells and formulate key design parameters of Li−S pouch cells that have high capacity, coulombic efficiency and long cycle life. Recent developments in Li−S pouch cells are then discussed, focusing on cathode and electrolyte design for polysulfide immobilization, accelerated sulfur conversion kinetics, and Li anode protection. A review of advanced characterization techniques suitable for Li−S pouch cell studies is also provided. Finally, viewpoints are offered on the remaining challenges and prospects to guide future research in scaling up Li−S technology for real‐world applications.

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

AbstractLithium‐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, repulsion, 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.

Ion-selective gel polymer electrolyte and cathode binder derived from a shared polyether to synergistically mitigate polysulfides shuttling in lithium sulfur batteries

As one kind of the most promising candidates for next-generation batteries, lithium-sulfur (Li-S) batteries with high theoretical energy density are still faced with the severe shuttle effect of polysulfides (PS) and safety issues caused by the flammable liquid electrolytes. To overcome the above challenges, an enhanced ion-selective strategy is proposed by collaboratively crosslinking a polyether containing epoxy groups with negatively charged aminated sodium lignosulfonate (ASL) and polar phytic acid (PA), respectively, to prepare a PS-repelling gel polymer electrolyte (AGPE) and a PS-anchoring cathode binder (PMG-PA) for Li-S batteries. The synergistically suppressed shuttle effect of PS makes the Li-S battery deliver a high capacity of 749.7 mAh g-1 over 200 cycles at 1 C with a super low capacity decay of 0.11 % per cycle, compared to the poor cycling performance (329.1 mAh g-1 over 200 cycles with a capacity decay of 0.26 % per cycle) of the conventional liquid electrolyte-based battery using polyvinylidene difluoride as the cathode binder. Furthermore, AGPE confines the liquid electrolyte within the polymer network, while ASL quenches free radicals during potential ignition events, thereby significantly enhancing the battery safety during operation. Therefore, the co-design strategy of ion-selective AGPE and PMG-PA cathode binder derived from a shared polyether offers a new way to mitigate polysulfides shuttling for safe and reliable Li-S batteries.

Lithium Metal Recovery from Sea Water by a Flexible and Scalable Membrane with Lithium-Ion Exclusive Channels.

Sea water is abundant in lithium reserves, and extracting lithium metal from it holds the potential to not only mitigate the shortage of lithium in light of the fast-growing electric vehicle industry, but also serve as an anode electrode to provide electricity. The task, however, is challenging due to the harsh reactions and low lithium concentration in sea water. Here, we present a single-channel strategy based on a flexible and scalable lithium ion-sieve membrane for efficient lithium extraction. Our composite membrane exhibits high separation factor βLi/Na of more than 2.87×107 with an ionic conductivity of 6.2×10-5 S cm-1. Lithium metal was electrolytically extracted from sea water through a hybrid-electrolyte system, which yielded a high Coulombic efficiency of 98.04 % and a low energy consumption of 17.4 kWh kgLi -1 at an optimized extracting current of 200 μA cm-2. The extracted lithium metal can be directly integrated into a lithium-sulfur battery, delivering an energy output of 395 Wh kg-1. To demonstrate its industrial viability, we also fabricate a pouch cell with Li metal anode extracted by an amplified extraction prototype. This study has the potential to dispel concerns of lithium depletion and facilitate the sustainable development of lithium-based energy storage systems.

Encapsulation Engineering of Sulfur into Magnesium Oxide for High Energy Density Li-S Batteries.

This study addresses the persistent challenge of polysulfide dissolution in lithium-sulfur (Li-S) batteries by introducing magnesium oxide (MgO) nanoparticles as a novel additive. MgO was integrated with sulfur using a scalable process involving solid-state melt diffusion treatment followed by planetary ball milling. XRD measurements confirmed that sulfur (S8) retains its orthorhombic crystalline structure (space group Fddd) following the MgO incorporation, with minimal peak shifts indicating slight lattice distortion, while the increased peak intensity suggests enhanced crystallinity due to MgO acting as a nucleation site. Additionally, Raman spectroscopy demonstrated sulfur's characteristic vibrational modes consistent with group theory (point group D2h) and highlighted multiwalled carbon nanotube (MWCNT's) D, G, and 2D bands, with a low ID/IG ratio (0.47), which indicated low defects and high crystallinity in the prepared cathode. The S-MgO composite cathode exhibited superior electrochemical behavior, with an initial discharge capacity (950 mA h g-1 at 0.1 C), significantly improved compared to pristine sulfur's. The presence of MgO effectively mitigated the polysulfide shuttle effect by trapping polysulfides, leading to enhanced stability over 400 cycles and the consistent coulombic efficiency of over 99.5%. After 400 cycles, EDS and SEM analyses confirmed the structural integrity of the electrode, with only minor fractures and slight sulfur content loss. Electrochemical impedance spectroscopy further confirmed the enhanced performance.

Exploration of Optimization Strategies for Locking Sulfur in 2D Layered/Polymer-Enveloped Cathode Composite for High Power Li-S Batteries.

In Lithium sulfur (Li-S) batteries the sulfur host material is a significant area of research that could impart enhanced conductivity and alleviate the shuttling of polysulfides. In the present study, graphene oxide- sulfur, GO-S was synthesized in melt diffusion method by exploring the two different strategies: Ambient (G2-M) and Inert (G2-T) conditions. Within the cathode, efficient storage of S with sufficient space in GO interlayers was outperformed by G2-T method. Further with PEDOT nanostructures enveloped by oxidative polymerisation proves to be a robust conductive layer and an adsorbing agent. It is evidenced physicochemically by XRD, FTIR, TGA, HR-SEM. Moreover, in addition to the supporting studies, high binding energies of 168.3 and 169.5 eV confirms the superior performance of PEDOT/GO-S (G3-T) as most suitable cathode within the system. The electrochemical behaviour of G3-T possess very low cell impedance with an excellent cyclic reversibility in CV during (de)lithiation process. At 0.1 C, an initial discharge capacity of 868 mAh g-1 has been achieved confirming a high catalytic activity with a low polarisation potential of (ΔE=0.25) inducing fast reaction kinetics. Thus potential locking of sulfur under inert condition is explored with a proven OCV of 2.3 V with red LED glow.

Advanced Li-S Battery Configuration Featuring Sulfur-Coated Separator and Interwoven rGO/CNT Fabric Current Collector.

The development of lithium-sulfur batteries (LSBs) marks a crucial milestone in advancing energy storage solutions essential for sustainable energy transitions. With high theoretical specific capacity, cost-effectiveness, and reduced ecological footprint, LSBs promise to enhance electric vehicle ranges, extend portable electronics' operational times, and stabilize grids integrated with renewable energy. However, challenges like complex processing, electrode instability, and poor cycling stability hinder their commercialization. This study introduces a novel battery design that addresses these issues by coating sulfur directly onto the separator instead of the current collector, demonstrating that active sulfur can be effectively utilized without being incorporated into the electrode structure. Using an interwoven substrate made from carbon nanotube (CNT) fabric adorned with reduced graphene oxide (rGO), this setup enhances manufacturing scalability, supports optimal sulfur utilization, and improves battery performance. The rGO decoration provides multiple highly conductive polysulfide trapping sites, enhancing active material reutilization, while the flexibility and mechanical strength of CNT fabric contribute to electrode integrity. This combination boosts electrical conductivity and polysulfide-capturing capability, effectively managing migrating sulfur species during charge-discharge cycles and mitigating sulfur loss and polysulfide shuttling. The results demonstrate superior cycling stability and efficiency, highlighting the potential of this approach in advancing LSB technology.

Dual-Functional Additive Bipyridine Cobalt Complex for Highly Efficient Kinetics and Lithium Regulation in Lithium–Sulfur Batteries

Dual-Functional Additive Bipyridine Cobalt Complex for Highly Efficient Kinetics and Lithium Regulation in Lithium–Sulfur Batteries

Melamine-based nanoscale porous organic frameworks as multifunctional separator modifiers to mitigate the polysulfide shuttle effect in lithium–Sulfur batteries

The shuttling of polysulfides between electrodes in lithium-sulfur (Li-S) batteries significantly impairs cycle stability. This study explores the use of melamine-based nanoscale porous organic frameworks (POFs) as polysulfide reservoirs to modify glass fiber (GF) separators. Melamine was reacted with dibromoalkanes of varying carbon chain lengths (n = 4, 8, and 12) to produce a series of POF materials, POF-Cn, with different nanoscale pore sizes and solubilities. The POF composites, POF-Cn/SP/PVP, which include conductive carbon Super P (SP) and a polyvinylpyrrolidone (PVP) binder, were coated onto GF membranes to create modified separators for Li-S batteries. Batteries with these modified GF separators exhibited higher initial capacities, improved rate performance, and better long-term cycle stability compared to those with non-modified separators. Among the POF composites, POF-C8/SP/PVP exhibited the best performance, with an initial specific capacity of 1392 mAh g-1 at 0.1C and a high capacity retention of 90% after 300 cycles at 0.5C. The enhanced capacity, stability, and rate performance are attributed to the nanoporous structure of POF-C8 and its high nitrogen content, which effectively traps soluble LiPSs and reduces their diffusion toward the Li anode. The good solubility of POF-C8 facilitates uniform dispersion in the modifying layer, promoting efficient polysulfide trapping and maximizing their utilization in electrochemical reactions, aided by the conductive SP in the composite.

A Review on Architecting Rationally Designed Metal-Organic Frameworks for the Next-Generation Li-S Batteries.

The modern era demands the development of energy storage devices with high energy density and power density. There is no doubt that lithium‒sulfur batteries (Li‒S) claim high theoretical energy density and have attracted great attention from researchers, but fundamental exploration and practical applications cannot converge to utilize their maximum potential. The design parameters of Li-S batteries involve various complex mechanisms, and their obliviousness has resulted in failure at the commercial level. This article presents a review on rationally designed metal-organic frameworks (MOFs) for improving next-generation Li-S batteries. The use of MOFs in Li-S batteries is of great interest because of their large surface area, porous structure, and selective permeability for ions. The working principles of Li-S batteries, the commercialization of Li-S batteries, and the use of MOFs as electrodes, electrolytes, and separators are critically examined. Finally, designed strategies (host structure, binder improvement, separator modification, lithium metal protection, and electrolyte optimization) are developed to increase the performance of Li-S batteries.

Construction of Ordered and Fast Lithium Ion Channels in Gel Electrolytes for Li-SPAN Batteries.

As one of the most promising battery systems, the lithium sulfur battery is expected to be widely used in fields of high energy density demands. Owing to the unique solid-solid conversion mechanism, there is no shuttle effect for the Li-SPAN (sulfurized polyacrylonitrile) battery. However, the compatibility between Li anode and carbonate electrolyte has not been resolved, which prevents the SPAN from practical applications. Herein, an organic-inorganic gel carbonate electrolyte is proposed to stabilize interphases and structures of both the anode and cathode, where polyimide (PI) is used for electrolyte gelation, which can assist in the uniform distribution of inorganic components at the electrolyte interface. Furthermore, ZnS nanodots loaded on two-dimensional MoS2 flakes provide abundant Li-ion diffusion paths, improve the transfer kinetic of Li ions, and induce uniform nucleation and deposition of Li. This gel electrolyte ensures Li symmetric cells a long-term cycle life of more than 900 h under the condition of deep lithium plating/stripping at 5 mAh cm-1. Li∥Cu cells exhibit a prolonged lifespan of 800 h with a CE of 98.3%. Furthermore, the Li-SPAN battery shows stability of more than 850 cycles, with the capacity retention of 85.1%. This work provides an approach for high-energy Li-SPAN batteries with carbonate-based electrolytes.

Spherical NiS2/Ni17S18–C accelerates ion transport and enhances kinetics for lithium-sulfur battery host material

Transition metal sulfides exhibit notable catalytic activity and possess a high theoretical specific capacity as host materials in lithium-sulfur batteries. However, their restricted conductivity and sluggish Li+ transport hinder their broader application. In this research, we developed a Ni-based metal-organic framework (Ni-MOF) using nitrogen-containing benzimidazole and coupled it with a highly conductive carbon nanotube (CNT) to form NixSy (NiS2–Ni17S18)–C/CNT. The N-doped carbon skeleton derived from the MOF enhances the adsorption and chemical anchoring of polysulfides, while the even distribution of NiS2 and Ni17S18 enhances the redox reaction kinetics. Additionally, the conductive CNT networks aid in rapid electron transport, resulting in improved sulfur utilization. Consequently, the NixSy-C/CNT@S electrode demonstrates an impressive initial specific capacity of 1468 mAh g−1 at 0.2C and maintains 904.4 mAh g−1 after 200 cycles. Moreover, NixSy-C/CNT@S displays exceptional cycle stability, with a capacity retention of 76.20 % and a decay rate of only 0.05 % per cycle after 500 cycles at 0.5C. This study paves the way for the development and synthesis of cathode materials with outstanding electrochemical performance in LSBs.

Study of the Activator Effects on the Specific Surface Area of Porous Carbon and its Performance as Lithium-Sulfur Battery Cathode

A study was conducted to investigate the effect of activator types KOH, ZnCl2, and H3PO4 on the specific surface area of porous carbon and its performance as a Li-S battery. Porous carbon was synthesized from candlenut shells through a carbonization process at 700 °C using three types of activator solutions with a concentration of 0.36 M. The porous carbon activated with KOH achieved the best results, with a specific surface area of 681 m²g-1. The porous carbon candlenut shell-sulfur (PCCS-S) composite was obtained by the solid-state reaction method in a ratio of 1:2.5 w% and heat-treated at 155 °C to form the PCCS-S composite. The PCCS-S composite was then made into a slurry and coated onto Al-foil to obtain a layer of electrodes with a thickness of 200 µm. The PCCS-S cathode was then assembled into a coin battery with lithium metal as the anode and an electrolyte of 1.0 M LiTFSi solution dissolved in 1,3-dioxolane (DOL) and 1,2-dimethoxyethane (DME) (v/v, 1:1). Charge-discharge characterization was carried out at a charge rate of 1 C for 50 cycles. Characterization shows that the performance of the PCCS-S KOH composite cathode Li-S battery is stable at a specific capacity of 324 mAhg-1 after the first 10 cycles, with an average Coulombic efficiency of around 86.8 %.

Vanadium doped in-plane 1T-2H molybdenum disulfide heterostructure as efficient electrocatalyst for lithium-sulfur batteries

The active electronic states in 1T-MoS2 are highly desirable for catalyzing polysulfides conversion. However, stable 1T-MoS2 is difficult to produce using common approaches. Herein, V uniformly doped in-plane 1T-2H heterostructured MoS2 nanosheets (V-MoS2) are prepared by a facile hydrothermal method with a polyoxometalate precursor containing periodic Mo and V atomic arrangement. The doping of V induces the phase transition from semiconducting 2H-MoS2 to metallic 1T-MoS2 and stabilizes the resulted 1T phase. Importantly, the incorporation of V not only modifies the surface electronic property of MoS2, enhancing the active site density, but also improves the adsorption of polysulfides and the catalytic efficiency for sulfur redox reactions. With these advantages, the Li-S batteries using V-MoS2 electrocatalyst achieve accelerated reaction kinetics and superior electrochemical performance. When the S loading of the cathode is 5.41 mg cm−2, a favorable discharge capacity of 4.98 mAh cm−2 is obtained with satisfying cycle stability. This work provides an efficient atomic engineering approach for the design of high performance electrocatalyst for Li-S batteries.