Search Results (215)

Lithium–sulfur batteries (LSBs) offer a theoretical energy density of 2600 Wh kg⁻¹ but suffer from the polysulfide shuttle effect, which causes rapid capacity decay and limits practical application. To address this, we developed a bifunctional separator coating using Ni-doped α-MnO₂ combined with carbon nanotubes (Ni-MnO₂/CNTs). Ni doping induces lattice expansion due to the larger Ni²⁺ ionic radius, modulating the electronic structure to create more active sites, enhance electrical conductivity, and improve polysulfide adsorption and redox kinetics. The needle-like morphology further strengthens physical/chemical confinement of polysulfides and accelerates conversion reactions. Batteries with the Ni-MnO₂/CNTs-modified separator deliver a high-rate capacity of 813 mAh g⁻¹ at 5 C and exhibit a low capacity decay rate of 0.0399% per cycle over 1500 cycles at 2 C. Even under high sulfur loading (∼10 mg cm⁻²) and lean electrolyte conditions (10 μL mg⁻¹), the cell maintains stable cycling with a decay rate of 0.0929% per cycle over 300 cycles at 0.2 C. This lattice-modulation strategy on commercial separators provides a simple, effective pathway toward high-energy-density, long-life LSBs. Full article

Lithium–sulfur (Li-S) battery technology has attracted significant research interest owing to sulfur’s remarkable theoretical capacity and exceptional energy density potential. Nevertheless, the low conductivity of sulfur and the “shuttle effect” pose challenges to its practical applications. To enhance electrochemical performance, this work developed nitrogen-doped graphene (NG) nanosheets as a separator coating for Li-S battery. As a modification layer for separators, NG acts as a physical barrier that prevents polysulfides from migrating across the separator to reach the anode, thereby mitigating the shuttle effect. Additionally, NG improves the conductivity of the separator and enhances wettability between the separator and electrolyte, facilitating uniform transmission of lithium ions. Notably, NG functionalized separators demonstrate excellent mechanical flexibility, contributing to improved cycle stability for batteries. Furthermore, theoretical calculations indicate a strong interaction between NG and lithium polysulfides (LiPSs), effectively inhibiting polysulfide migration. The Li-S battery utilizing the NG modified separator maintains a capacity retention rate of 51.5% after 100 cycles at 0.1 C with a sulfur loading of 1.47 mg/cm² and exhibits a capacity decay rate of only 0.092% after 500 cycles at a discharge rate of 1 C. This work highlights the potential advantages of employing NG as a separator coating layer in enhancing the electrochemical performance of the Li-S battery. Full article

Lithium–sulfur (Li–S) batteries have emerged as a promising next-generation energy storage solution as the capacity demands on lithium-ion systems begin to exceed practical limits. In a global push for renewable energy and sustainable practices, Li–S technology offers several compelling advantages. Both lithium and sulfur are relatively inexpensive (especially compared to the transition metals used in lithium-ion cells), and Li–S batteries are easier and less costly to recycle. Moreover, Li–S chemistry carries a theoretical energy density about five times greater than that of current lithium-ion batteries, making it attractive for high-energy-density applications. Because of these advantages, research interest in Li–S batteries remains high despite significant challenges that still limit their performance and lifespan. However, despite these advantages, several fundamental challenges limit the practical deployment of Li–S batteries, including the polysulfide shuttle effect, large volume expansion of sulfur during cycling, low intrinsic electrical conductivity of sulfur and its discharge products, and instability of the lithium metal anode caused by dendrite formation. This paper explains the working principles of Li–S batteries, analyzes the key challenges and recent achievements in their development, and surveys various mechanical engineering applications for which Li–S batteries are being explored, as well as prospects for their future commercialization and sustainability. Full article

Lithium–sulfur (Li-S) batteries hold great promise for next-generation energy storage, offering high theoretical energy density and cost-effectiveness. However, challenges like sulfur’s low conductivity, polysulfide dissolution, and significant volume changes limit their practical application. This study addresses these issues by investigating porosity-engineered carbon hosts, specifically potassium hydroxide (KOH)-activated Black Pearl carbons (BP2000, BP1300, and BP800). Varying KOH-to-carbon ratios allowed precise tailoring of micro- and mesoporous structures, optimizing sulfur loading, electrolyte infiltration, and ion transport. Composites were characterized by TGA, NLDFT, SEM, XRD, and FTIR and electrochemically (cycling, CV, EIS). The KOH-modified BP2000 1:1 cathode, exhibiting the highest mesopore volume increase, demonstrated superior electrochemical performance, including enhanced cycling stability, rate capability, and reduced charge-transfer resistance. These findings emphasize the importance of optimizing pore distribution in carbon hosts for high-performance Li-S batteries and provide valuable insights for advanced energy storage material design. Full article

Suppressing the polysulfide shuttle effect and accelerating the sulfur redox kinetics remain pivotal challenges for advancing the practical viability of lithium–sulfur batteries (LSBs). In this study, an iodine-doped carbon nitride (I-CN) material was synthesized via a one-step annealing strategy and employed as a metal-free sulfur cathode host. Compared to its pristine counterpart, I-CN exhibits a substantially increased specific surface area, which facilitates the homogeneous dispersion of sulfur species. More importantly, the incorporation of iodine atoms disrupts the equilibrium of the electron cloud distribution within the CN framework, leading to enhanced electron delocalization. This electronic modulation not only significantly improves the charge transport properties of carbon nitride but also strengthens the adsorption of lithium polysulfides (LiPS) and promotes Li₂S nucleation, thereby enabling fast and durable sulfur redox reactions. Benefiting from these synergistic effects, the S@I-CN electrode achieves high sulfur utilization, delivering an initial discharge capacity of 1341.9 mAh g⁻¹ at 0.1C. Even at a high current density of 5C, a remarkable reversible capacity of 472.7 mAh g⁻¹ is retained. Notably, the electrode retains 66.2% of its initial capacity after 800 cycles, demonstrating excellent long-term cycling stability. This halogen-based heteroatom doping strategy thus not only enhances the electrochemical performance of carbon nitride materials in LSBs through the rational manipulation of electron delocalization, but also offers a promising direction for the design of novel metal-free electrocatalysts in related energy conversion systems. Full article

Lithium–sulfur (Li-S) batteries promise high energy density and low cost but are hindered by polysulfide shuttling, sluggish redox kinetics, poor sulfur conductivity, and lithium dendrite formation. Here, a targeted cation-substitution strategy is applied to Co₃O₄ spinels by replacing octahedral Co³⁺ sites with trivalent Al³⁺ or Fe³⁺, generating Al₂CoO₄ and Fe₂CoO₄ with exclusively tetrahedral Co²⁺ sites. Structural characterizations confirm the reconstructed cationic environments, and electrochemical analyses show that both substituted spinels surpass pristine Co₃O₄ in LiPS adsorption and catalytic activity, with Al₂CoO₄ delivering the strongest LiPS binding, fastest Li⁺ transport, and most efficient redox conversion. As a result, Li-S cells equipped with Al₂CoO₄-modified separators exhibit an initial capacity of 1327.5 mAh g⁻¹ at 0.1C, maintain 883.3 mAh g⁻¹ after 200 cycles, and deliver 958.6 mAh g⁻¹ at 1C with an ultralow decay rate of 0.034% per cycle over 1000 cycles. These findings demonstrate that selective Co-site substitution effectively tailors spinel chemistry to boost polysulfide conversion kinetics, ion transport, and long-term cycling stability in high-performance Li-S batteries. Full article

With the increasing demand for high-energy-density energy storage systems in electric vehicles, smart grids, and portable electronic devices, the energy density of traditional lithium-ion batteries is approaching its theoretical limit. Lithium-sulfur (Li-S) batteries are regarded as strong candidates for next-generation high-performance energy storage systems due to their high theoretical energy density (2567 Wh kg⁻¹), low cost, and environmental friendliness. However, the commercialization of Li-S batteries still faces key challenges such as the shuttle effect, sluggish reaction kinetics, volume expansion, and lithium anode corrosion. To address these issues, researchers have developed various functional materials and structural design strategies, among which heterostructures and nanocage host materials show significant advantages. This review systematically summarizes the basic principles, key problems, and solving strategies of lithium-sulfur (Li-S) batteries, focusing on the role of nanocage heterostructures in enhancing polysulfide adsorption, catalytic conversion, and structural stability, and outlines their future development path in high-energy-density Li-S batteries. Full article

Lithium–sulfur (Li-S) batteries are renowned for their high theoretical energy density and low cost, yet their practical implementation is hampered by the polysulfide shuttle effect and sluggish redox kinetics. Herein, a sol–gel strategy is proposed to engineer a multifunctional MXene/Fe₃O₄ composite as an efficient mediator for the cathode interlayer. The synthesized composite features Fe₃O₄ nanospheres uniformly anchored on the highly conductive Ti₃C₂T_x MXene lamellae, forming a unique 0D/2D conductive network. This structure not only provides abundant polar sites for strong chemical adsorption of polysulfides but also significantly enhances charge transfer, thereby accelerating the conversion kinetics. As a result, the Li-S battery based on the MXene/Fe₃O₄ interlayer delivers a high initial discharge capacity of 1367.1 mAh g⁻¹ at 0.2 C and maintains a stable capacity of 1103.4 mAh g⁻¹ after 100 cycles, demonstrating an exceptionally low capacity decay rate of only 0.19% per cycle. Even at a high rate of 1 C, a remarkable capacity of 1066.1 mAh g⁻¹ is retained. Electrochemical analyses confirm the dual role of the composite in effectively suppressing the shuttle effect and catalyzing the polysulfide conversion. This sol–gel engineering approach offers valuable insight into the design of high-performance mediators for advanced Li-S batteries. Full article

This comprehensive review examines the transformative role of metal–organic frameworks (MOFs) in advancing battery separator technology to address critical safety challenges in rechargeable lithium metal batteries. MOF-based separators leverage their highly specific surface area, tunable pore structures, and functionalized organic ligands to enable precise ion-sieving effects, uniform lithium-ion flux regulation, and dendrite suppression—significantly mitigating risks of internal short circuits and thermal runaway. We systematically analyze the mechanisms by which classical MOF families (e.g., ZIF, UiO, MIL series) enhance separator performance through physicochemical properties such as electrolyte wettability, thermal stability (>400 °C), and mechanical robustness. Furthermore, we highlight innovative composite strategies integrating MOFs with polymer matrices (e.g., PVDF, PAN) or traditional separators, which synergistically improve ionic conductivity while inhibiting polysulfide shuttling in lithium–sulfur batteries and side reactions in aqueous zinc-ion systems. Case studies demonstrate that functionalized MOF separators achieve exceptional electrochemical outcomes: Li–S batteries maintain >99% Coulombic efficiency over 500 cycles, while solid-state batteries exhibit 2400 h dendrite-free operation. Despite promising results, scalability challenges related to MOF synthesis costs and long-term stability under operational conditions require further research. This review underscores MOFs’ potential as multifunctional separator materials to enable safer, high-energy-density batteries and provides strategic insights for future material design. Full article

Through atomic-scale characterization of a single cobalt atom anchored in a pyridinic N₃ vacancy of graphene (Co-N₃-gra), this study computationally explores three interconnected functionalities mediated by cobalt’s electronic configuration. Quantum-confined molecular prototypes extend prior bulk models, achieving a competitive catalytic activity for CO oxidation via Langmuir–Hinshelwood pathways with a 0.85 eV barrier. These molecular prototypes’ discrete energy states facilitate single-electron transistor operation, enabling sensitive detection of NO, NO₂, SO₂, and CO₂ through adsorption-induced conductance modulation. When applied to lithium–sulfur batteries using periodic Co-N₃-gra, cobalt sites enhance polysulfide conversion kinetics and suppress the shuttle effect, with the Li₂S₂→Li₂S step identified as the rate-limiting process. Density functional simulations provide atomic-scale physicochemical characterization of Co-N₃-gra, revealing how defect engineering in 2D materials modulates electronic structures for multifunctional applications. Full article

Metal–organic frameworks (MOFs) and their derivatives have emerged as promising candidates for separator engineering in lithium–sulfur batteries (LSBs). This is attributed to their structural tunability, high porosity, and chemical versatility. Despite their potential, challenges such as lithium polysulfide (LiPS) shuttling, sluggish redox kinetics, and poor interfacial stability still hinder the practical deployment of LSBs. This review examines recent advances in MOF- and MOF derivative-based materials for separator modification, focusing on design strategies, functional mechanisms, and electrochemical performance. Pristine MOFs are classified into the following three key structural tuning strategies: control of the pore microenvironment, engineering of metal sites, and enhancement of electrical conductivity. Meanwhile, MOF derivatives are examined using compositional categories to highlight their distinct chemical characteristics and catalytic functionalities for LiPS regulation. Key findings demonstrate that these materials can effectively suppress polysulfide migration, accelerate LiPS redox reactions, and improve lithium-ion transport across the separator. The review also identifies remaining challenges and suggests future perspectives for bridging material-level innovations with system-level applications. Overall, MOF-based separator materials represent a versatile and impactful approach for advancing the electrochemical performance and stability of next-generation LSBs. Full article

Lithium–iron disulfide (Li-FeS₂) batteries are plagued by the polysulfide shuttle effect and cathode structural degradation, which significantly hinder their practical application. This study proposes a dual-strategy design that combines a polyacrylonitrile–carbon nanotube (PAN-CNT) composite cathode and a polyvinylidene fluoride (PVDF)-conductive carbon-coated separator to synergistically address these bottlenecks. The PAN-CNT binder establishes chemical anchoring between polyacrylonitrile and FeS₂, enhancing electronic conductivity and mitigating volume expansion. Specifically, the binder boosts the initial discharge capacity by 35% while alleviating the stress-induced pulverization associated with volume changes. Meanwhile, the PVDF-conductive carbon-coated separator enables effective polysulfide trapping via dipole–dipole interactions between PVDF’s polar C-F groups and Li₂S_x species while maintaining unobstructed ion transport with an ionic conductivity of 1.23 × 10⁻³ S cm⁻¹, achieving a Coulombic efficiency of 99.2%. The electrochemical results demonstrate that the dual-modified battery delivers a high initial discharge capacity of 650 mAh g⁻¹ at 0.5 C, with a capacity retention rate of 61.5% after 120 cycles, significantly outperforming the control group’s 47.5% retention rate. Scanning electron microscopy and electrochemical impedance spectroscopy confirm that this synergistic design suppresses polysulfide migration and enhances interfacial stability, reducing the charge transfer resistance from 26 Ω to 11 Ω. By integrating polymer-based functional materials, this work presents a scalable and cost-effective approach for developing high-energy-density Li-FeS₂ batteries, providing a practical pathway to overcome key challenges in their commercialization. Full article

Commercialization of lithium-sulfur (Li-S) batteries is critically hampered by the severe lithium polysulfide shuttle effect. Hence, designing multifunctional materials that synergistically provide physical confinement of polysulfides, chemical entrapment, and catalytic promotion is a viable route for improving Li-S battery performance. Herein, graphitic carbon nitride (g-C₃N₄) with abundant nitrogen atoms was used as the chemical adsorption material to realize a “physical-chemical” dual confinement for polysulfides. Furthermore, the integration of CNTs with g-C₃N₄ is intended to substantially enhance the conductivity of the cathode material. Consequently, the synthesized g-C₃N₄/CNT composite, which functions as an effective polysulfide immobilizer, significantly improved the cycling stability and discharge capacity of Li-S batteries. This enhancement can be attributed to its potent adsorption and catalytic activities. Li-S cells utilizing g-C₃N₄/CNT cathodes exhibit exceptional discharge capacity and notable rate capability. Specifically, after 100 cycles at 0.2 C, the discharge capacity was 701 mAh g⁻¹. Furthermore, even at a high rate of 2 C, a substantial capacity of 457 mAh g⁻¹ was retained. Full article

Severe polysulfide shuttling and sluggish redox kinetics critically hinder lithium–sulfur (Li-S) battery commercialization. In this study, a multifunctional diatomite (DE)/TiO₂/MoS₂/N-doped carbon nanofiber (NCNF) composite separator was fabricated via hydrothermal synthesis, electrospinning, and carbonization. DE provides dual polysulfide suppression, encompassing microporous confinement and electrostatic repulsion. By integrating synergistic catalytic effects from TiO₂ and MoS₂ nanoparticles, which accelerate polysulfide conversion, and conductive NCNF networks, which facilitate rapid charge transfer, this hierarchical design achieves exceptional electrochemical performance: a 1245.6 mAh g⁻¹ initial capacity at 0.5 C and 65.94% retention after 200 cycles. This work presents a rational multi-component engineering strategy to suppress shuttle effects in high-energy-density Li-S batteries. Full article

Films of functionalised multiwalled carbon nanotubes (MWCNTs) were fabricated as interlayers (interfacial layers between the cathode and separator) in a lithium–sulfur battery (LSB). Phenylsulfonate functionalisation of commercial MWCNTs was achieved via diazotisation to attach lithium phenylsulfonate groups and was characterised by IR and XPS spectroscopies. SEM-EDX showed sulfur and oxygen colocations due to the sulfonate groups on the interlayer surface. However, CHNS elemental microstudies showed a low degree of functionalisation. Without an interlayer, the LSB produced stable cycling at a capacity of 600 mA h g⁻¹_sulfur at 0.05 C for 40 cycles. Using an unfunctionalised interlayer as a control gave a capacity of 1400 mA h g⁻¹_sulfur for the first cycle but rapidly decayed to the same 600 mA h g⁻¹_sulfur at the 40th cycle at 0.05 C, suggesting a high degree of polysulfide shuttling. Adding a lithium phenylsulfonated interlayer gave an initial capacity increase to 1100 mA h g⁻¹_sulfur that lowered to 800 mA h g⁻¹_sulfur at 0.05 C by the 40th cycle, showing an increase in charge storage (33%) relative to the other cells. This performance increase has been attributed to lessened polysulfide shuttling due to repulsion by the phenylsulfonate groups, increased conductivity at the separator-cathode interface and an increase in surface area. Full article