Sulfur Host Research Articles

Preparation of Biomass-Derived High Specific Surface Area Carbon with Titanium Nitride Nanoparticles for Lithium-Sulfur Batteries

The widespread challenges facing lithium-sulfur batteries, including the low electrical conductivity of sulfur and its species, electrode volume fluctuations during cycling, and the lithium polysulfides shuttle effect, have hindered their commercialization and practical utility [1,2].Our study addresses these issues by incorporating titanium nitride (TiN) nanoparticles onto high specific surface area porous carbon, exploring this composite's potential as both a sulfur cathode host and separator modifier. The synthesis of the carbon/TiN composite involved two key stages: firstly, the in-situ growth of titanium dioxide (TiO2) nanoparticles on the carbon surface utilizing titanium tetrachloride as a precursor; secondly, the conversion of the TiO2 nanoparticles to TiN nanoparticles through carbothermal nitridization (thermal treatment at 1400 ℃ for 4 hours in a nitrogen medium) [3,4].The lithium-sulfur cell employing the prepared C/TiN-25%@S cathode exhibited an initial discharge capacity of 1155 mAh g-1 at 0.2 C, maintaining a capacity exceeding 700 mAh g-1 after 100 cycles. Notably, the lithium-sulfur cell utilizing the C/TiN-25%@S cathode and a C/TiN-modified separator demonstrated enhanced cycling performance, delivering an initial discharge capacity of 1623 mAh g-1 with retention of over 1126 mAh g-1 after 100 charge/discharge cycles at 0.2 C. Acknowledgments This research was funded by the Science Committee of the Ministry of Education and Science of the Republic of Kazakhstan (Grant No. AP19677708).

Single Atom Catalyst Anchored on Nitrogen-Doped Porous Carbon As an Effective Sulfur Host for Lithium-Sulfur Batteries

Lithium-sulfur batteries (LSBs) are considered highly promising for next-generation energy storage due to their high theoretical specific capacity and energy density. However, challenges such as the insulating nature of sulfur cathodes, the detrimental shuttle effect of lithium polysulfides (LiPSs), and sluggish conversion kinetics of LiPSs during charge/discharge cycles impede their commercial viability. In this study, we employed a facile ‘dissolution-carbonization’ approach to synthesize nitrogen-coordinated monometallic atomic catalysts anchored on mesoporous carbon to promote surface-mediated reactions of LiPSs. The hierarchical porous carbon support physically confines the sulfur species, while the introduction of single atoms efficiently captures polysulfide intermediates and facilitates their redox conversion kinetics with a lower activation energy barrier. The synergistic effect of the single atom and nitrogen-rich porous carbon (NC) significantly enhances reaction kinetics and sulfur species utilization. Consequently, LSBs incorporating single-atom catalysts (SACs) demonstrate remarkable performance metrics, including high-capacity retention (824.2 mAh g−1), superior Coulombic efficiency (>98.5%), low-capacity decay rate (0.042% per cycle) after 500 cycles at 1 C, and excellent rate capability (776 mA h g–1 at 3 C). This work presents an effective strategy that combines the functions of a nanoporous material host and SACs for lithium-sulfur batteries.

In-situ banana fiber-modified carbonized bacterial cellulose as a free-standing and binder-free cathode host for potassium-sulfur batteries

To meet the growing energy demand for large-scale applications, potassium-sulfur batteries (KSBs) have gained enormous attention owing to their high energy density, natural abundance, and specific capacity. Nevertheless, the shuttle effect, the insulating nature of sulfur, and the large volume change hinder the development of KSBs. To address the different challenges of KSBs, we report eco-friendly and biodegradable in-situ banana fiber-modified carbonized bacterial cellulose as a free-standing and binder-free cathode (sulfur) host. The catholyte K2S6 is used as active sulfur for cell fabrication owing to a high sulfur loading and even distribution of active material. However, introducing the catholyte induces the potassium side reaction by reacting to it. Therefore, carbonized bacterial cellulose is used as an interlayer to reduce the notorious polysulfide shuttle effect. As a result, the fabricated cell delivers a specific capacity of 437, 354, and 193 mAh g-1 at the current density of 0.2, 0.7, and 1.2 C, respectively. During the long cycling, the cell shows excellent electrochemical performance for 200 cycles with a capacity retention of 78 % at 0.7 C. This work paves the way to utilize an eco-friendly and cost-effective approach to fabricate a high-performance KSB.

Electrochemically Active MoO3/TiN Sulfur Host Inducing Dynamically Reinforced Built-in Electric Field for Advanced Lithium-Sulfur Batteries.

Although various electrocatalysts have been developed to ameliorate the shuttle effect and sluggish Li-S conversion kinetics, their electrochemical inertness limits the sufficient performance improvement of lithium-sulfur batteries (LSBs). In this work, an electrochemically active MoO3/TiN-based heterostructure (MOTN) is designed as an efficient sulfur host that can improve the overall electrochemical properties of LSBs via prominent lithiation behaviors. By accommodating Li ions into MoO3 nanoplates, the MOTN host can contribute its own capacity. Furthermore, the Li intercalation process dynamically affects the electronic interaction between MoO3 and TiN and thus significantly reinforces the built-in electric field, which further improves the comprehensive electrocatalytic abilities of the MOTN host. Because of these merits, the MOTN host-based sulfur cathode delivers an exceptional specific capacity of 2520mA h g-1 at 0.1 C. Furthermore, the cathode exhibits superior rate capability (564mA h g-1 at 5 C), excellent cycling stability (capacity fade rate of 0.034% per cycle for 1200 cycles at 2 C), and satisfactory areal capacity (6.6mA h cm-2) under a high sulfur loading of 8.3mg cm-2. This study provides a novel strategy to develop electrochemically active heterostructured electrocatalysts and rationally manipulate the built-in electric field for achieving high-performance LSBs.

Synthesis and interface construction of Fe0.5Co0.25Ni0.25S2 cathode material for high performance lithium-sulfur batteries

In lithium-sulfur batteries, carbon is commonly used as a host for sulfur in the cathode. However, carbon materials alone do not provide additional capacity and prevent the shuttle effect. This study aimed to create a novel material, Fe0.5Co0.25Ni0.25S2 (FCN211), by adjusting the molar ratios of Fe, Co and Ni. Analysis revealed that while the morphology of FCN-type materials remained consistent, there were notable differences in element distribution at the nanoscale. The modified FCN211@S/GC-CLCS cathode demonstrated a specific capacity of almost 1500mAh/g at 1 mA cm−2. Even with a sulfur content of approximately 6 mg cm−2, it maintained a specific capacity of 611mAh/g after 400 cycles at 1.5 mA cm−2. This study shows that by increasing the content of Fe element and adopting ion–electron dual-effect coating interface optimization, the anion redox capacity of FCN material in lithium-sulfur batteries can be further utilized.

Carbon‐Based Cathode Design for Next‐Generation Potassium‐Sulfur Batteries: Status and Perspective

ABSTRACTThe increasing concern for environmental pollution has fastened the development of energy storage devices. Among various devices, lithium‐ion battery (LIB) technology has been leapfrogged owing to its stable performance for various applications ranging from electronic gadgets to electric vehicles (EVs). For ever‐increasing number of EVs has increased the demand for batteries increasing the overall cost. An alternative energy storage device that can replace the dependence on lithium reserves can be another game changer in this area. Potassium‐sulfur batteries (KSBs) have attracted enormous attention owing to the higher abundance of sulfur and potassium. In addition, sulfur bears the highest capacity as a cathodic material (nearly five times higher than the commercial LIBs) and when clubbed with potassium anode can deliver a theoretical energy density of 914 Wh/kg (significantly higher for EVs). However, KSB development is still in the nascent stage owing to the intrinsic challenges including insulating sulfur, volume variation, and shuttle effect of polysulfides. In addition, unstable potassium anode and its dendrite formation is another thorny problem for KSB. The use of carbon matrices for cathode fabrication has been proven to be an excellent choice by initial research on KSB and experience with other metal‐sulfur batteries. This can be related to the higher electronic conductivity of carbon, easy tunability, high specific surface area, and porous morphology. This review is an attempt to show the usage of carbon as a sulfur host for KSBs and its performance. Further, we shed light on flexible and binder‐free carbon electrodes for the development of KSBs, which can be adopted to develop flexible batteries to be used in wearable devices. Finally, we present our perspective for developing a high‐performance carbon‐based cathode material for developing a reliable and long‐cycle life KSB.

Dual-function hollow MoS2 nanocages decorated on graphene sheets as efficient sulfur hosts for advanced lithium-sulfur batteries

Due to the presence of polysulfitabde shuttling, serious electrode expansion, and the low electrical conductivity of sulfur materials at room temperature, the commercialization of Li-S batteries is still not feasible. In this study, we have synthesized unique hollow molybdenum disulfide nanocages/reduced graphene oxide (H-MoS2/rGO) composites to be employed as highly effective cathodes for Li-S batteries. In this well-designed structure, the hollow MoS2 nanocages are tightly bound by C-O-Mo bonds and uniformly distributed across the graphene sheets. The dual-function MoS2 nanocages can adsorb polysulfides by Mo-S bond and accelerate the conversion reaction of S8 and Li2S. Moreover, the 3D rGO network with abundant pores effectively reduces the diffusion path and enhances the rapid transport of electrons and ions. The hybrid H-MoS2/rGO cathodes with these advantages exhibit a remarkable initial discharge capacity of 801.7 mAh g−1 at 1 C, as well as a high specific discharge capacity of 533.2 mAh g−1 is remained over 500 cycles.

Enhancing Lithium-Sulfur Battery Performance with MXene: Specialized Structures and Innovative Designs.

Established in 1962, lithium-sulfur (Li-S) batteries boast a longer history than commonly utilized lithium-ion batteries counterparts such as LiCoO2 (LCO) and LiFePO4 (LFP) series, yet they have been slow to achieve commercialization. This delay, significantly impacting loading capacity and cycle life, stems from the long-criticized low conductivity of the cathode and its byproducts, alongside challenges related to the shuttle effect, and volume expansion. Strategies to improve the electrochemical performance of Li-S batteries involve improving the conductivity of the sulfur cathode, employing an adamantane framework as the sulfur host, and incorporating catalysts to promote the transformation of lithium polysulfides (LiPSs). 2D MXene and its derived materials can achieve almost all of the above functions due to their numerous active sites, external groups, and ease of synthesis and modification. This review comprehensively summarizes the functionalization advantages of MXene-based materials in Li-S batteries, including high-speed ionic conduction, structural diversity, shuttle effect inhibition, dendrite suppression, and catalytic activity from fundamental principles to practical applications. The classification of usage methods is also discussed. Finally, leveraging the research progress of MXene, the potential and prospects for its novel application in the Li-S field are proposed.

Promoting polysulfides conversion by hexagonal-like V-MOF-derived VC-doped carbon nanotubes for lithium-sulfur batteries

Lithium-sulfur batteries (LSBs) are one of the representatives of a new generation of high-performance batteries, due to their large theoretical specific discharge capacity, high energy density and low cost et al. However, shuttle effect and slow conversion kinetics of polysulfides (LiPSs) hinder the performance of LSBs. In order to mitigate shuttle effect, metal-organic frameworks are introduced. Carbon nanotubes (CNTs) is used as composite cathode, due to their high electrical conductivity. V-MOF/CNTs-derived hexagonal VC/CNTs nanosheets are successfully synthesized and used as the sulfur host. VC/CNTs nanosheet with mesoporous structure can provide a lot of active sites. VC nanosheets are uniformly distributed and interconnected with CNTs to form a conductive network structure. VC/CNTs has excellent chemical adsorption and catalytic properties on polysulfides, which can improve the redox reaction kinetics and the adsorption capability. Due to the synergistic effects, S/VC/CNTs has an excellent cycling stability. S/VC/CNTs shows a significant initial specific capacity of 1370 mAh g−1 at 0.1 C. Capacity decay rate per cycle is about 0.037 % After 500 cycles at 0.5 C, the Coulomb efficiency is nearly to 100 %. The results show that the introduction of VC/CNTs composites with special hexagonal structure can accelerate the catalytic electrochemical reaction, and the dissolution and diffusion of polysulfides are well controlled.

Hollow CoP-FeP cubes decorating carbon nanotubes heterostructural electrocatalyst for enhancing the bidirectional conversion of polysulfides in advanced lithium-sulfur batteries

The sluggish redox reaction kinetics and “shuttle effect” of lithium polysulfides (LPSs) impede the advancement of high-performance lithium-sulfur batteries (LSBs). Transition metal phosphides exhibit distinctive polarity, metallic properties, and tunable electron configuration, thereby demonstrating enhanced adsorption and electrocatalytic capabilities towards LPSs. Consequently, they are regarded as exceptional sulfur hosts for LSBs. Moreover, the introduction of a heterogeneous structure can enhance reaction kinetics and expedite the transport of electrons/ions. In this study, a composite of hollow CoP-FeP cubes with heterostructure modified carbon nanotube (CoFeP-CNTs) was fabricated and utilized as sulfur host in advanced LSBs. The presence of carbon nanotubes (CNTs) facilitates enhanced electron and Li+ transport. Meanwhile, the active sites within the heterogeneous interface of CoP-FeP suppress the “shuttle effect” and enhance the conversion kinetics of LPSs. Therefore, the CoFeP-CNTs/S electrode exhibited exceptional cycling stability and demonstrated a capacity attenuation of merely 0.051 % per cycle over 600 cycles at 1C. This study presents a highly effective tactic for synthesizing dual-acting transition metal phosphides with heterostructure, which will play a pivotal role in advancing the development of efficient LSBs.

Self-assembled 3D CoSe-based sulfur host enables high-efficient and durable electrocatalytic conversion of polysulfides for flexible lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries are considered as promising candidates for next-generation energy storage systems. However, the commercial applications are severely limited by the sluggish kinetics and shuttling effect. Herein, we have designed an integrated free-standing functional CoSe-CNF-GO-MXene (CCGM) sulfur host with a “point-line-plane” 3D porous structure for Li-S batteries. The two-dimensional (2D) graphene, MXene and one-dimensional (1D) nanocellulose fibers combined with zero-dimensional (0D) transition metal selenide (CoSe) shows good electrical conductivity and enhanced catalytic performance, respectively. Additionally, the rationally designed porous structure (from 0D to 3D) demonstrates well-connected ion/electron transport channels, conferring the good kinetic performance. Electrochemical tests show that CoSe catalytic materials with moderate adsorption energies can catalyse both precipitation and dissolution processes of Li2S, enabling fast conversion kinetics. The density functional theory (DFT) calculations show that the synergistic effect of CoSe, Ti3C2Tx, and graphene can improve the chemisorption and catalytic performance. As a result, the 3D porous S@CCGM cathode exhibits a high initial discharge capacity of 1205.1 mAh g−1 at 0.2C and good long-term cycling performance with a low decay rate of 0.055 % per cycle at 1C. Furthermore, the gel electrolyte Li-S pouch cell successfully passes the 0–180° bending test, nailing test, and cutting test. Such design offers a new perspective for the commercialization of safe and flexible electrochemical energy-storage devices especially in Li-S batteries.

Fabrication of Fe/KB Composite as Sulfur Host for Li-S Battery.

Lithium sulfur battery is a novel kind of secondary battery which has high energy density, however its application is greatly affected by the shuttle effect of polysulfides generated in the redox reaction of cathode electrode. Metal active sites are supposed as effective catalysts which can absorb and accelerate the conversion efficiency of lithium polysulfides, thus the shuttle effect will be alleviated. In this work, we conducted a simple way to prepare a metal Fe doped ketjen black to serve as the sulfur host of lithium sulfur battery. Ketjen black has a large specific surface area and rich porous structure, while Fe nanodot is an excellent catalyst for lithium polysulfides. Because of these advantages, the Fe/KB host can effectively confine a large amount of active material and accelerate its, therefore the Fe/KB-S cathode electrode show an excellent electrochemical performance.

Facile construction of porous carbon fibers from coal pitch for Li-S batteries

Coal pitch, an important by-product in the coal coking industry with a high output, is a low-cost and high-carbon yield precursor for the manufacturing of high-value carbon materials. Herein, N/O co-doped carbon fiber (CFCP), fabricated by electrospinning using pre-oxidized coal pitch as the precursor, was employed as the sulfur host for Li-S batteries. The presence of more pyrrolic N and graphic N in CFCP than carbon fiber made from polyacrylonitrile benefits the adsorption of lithium polysulfide and the battery’s life. Sulphur-CFCP cathode (S@CFCP) exhibited excellent specific capacity and cyclability, with a specific capacity of 701.1 mAh/g and a low capacity decay rate of 0.088% per cycle over 200 cycles at 2.0 C, respectively. The high ion diffusion rate, low charge transfer resistance, and effective conversion of lithium polysulfides enable the high electrochemical performance of S@CFCP.

High-Entropy Metal Nitride Embedded in Concave Porous Carbon Enabling Polysulfide Conversion in Lithium-Sulfur Batteries.

The practical implementation of lithium-sulfur batteries is severely hindered by the rapid capacity fading due to the solubility of the intermediate lithium polysulfides (LiPSs) and the sluggish redox kinetics. Herein, high-entropy metal nitride nanocrystals (HEMN) embedded within nitrogen-doped concave porous carbon (N-CPC) polyhedra are rationally designed as a sulfur host via a facile zeolitic imidazolate framework (ZIF)-driven adsorption-nitridation process toward this challenge. The configuration of high-entropy with incorporated metal manganese (Mn) and chromium (Cr)will optimize the d-band center of active sites with more electrons occupied in antibonding orbitals, thus promoting the adsorption and catalytic conversion of LiPSs. While the concave porous carbon not only accommodates the volume change upon the cycling processes but also physically confines and exposes active sites for accelerated sulfur redox reactions. As a result, the resultant HEMN/N-CPC composites-based sulfur cathode can deliver a high specific capacity of 1274 mAh g-1 at 0.2C and a low capacity decay rate of 0.044% after 1000 cycles at 1C. Moreover, upon sulfur loading of 5.0mg cm-2, the areal capacity of 5.0mAhcm-2 can still be achieved. The present work may provide a new avenue for the design of high-performance cathodes in Li-S batteries.

In-situ chemical state transition of Ni nano-metal catalytic site promotes the reaction kinetics of lithium-sulfur battery

Researchers have extensively explored the implementation of metal-based catalysts to address the slow conversion kinetics of lithium polysulfides (LiPSs) in lithium-sulfur (Li-S) batteries. However, the elucidation of foundational aspects, such as the in-situ transformation processes of monometallic catalysts within the Li-S battery reaction milieu, as well as the chemical states of resultant catalytic active centers, remains elusive. In this study, a flexible material (CBC/Ni) was prepared, consisting of a carbonized bacterial cellulose framework uniformly loaded with nickel nanoparticles, serving as a sulfur host. Through in-situ XRD and in-situ Raman studies, it was demonstrated that the nanoscale Ni catalyst in the S@CBC/Ni electrode undergoes an interaction with LiPSs during the operation of Li-S batteries, transforming into the chemical state of NiS2 and subsequently acting as a new active center to promote the conversion of LiPSs in the subsequent cycling process. Due to these advantageous characteristics, the S@CBC/Ni cathode delivers a high-rate capacity of 798.7 mAh/g at 2C, with an average capacity decay rate of only 0.064% over 500 cycles. This work provides a theoretical reference for the in-situ chemical transformation and functionality of nanoscale metal catalysts in the Li-S system.

Atomically dispersed Co/Mn immobilized on O, N dual doped hollow carbon spheres as sulfur host for lithium sulfur batteries

The regulation of the chemical coordination environment in the electrocatalyst can effectively suppress the shuttle effect of sulfur species in lithium-sulfur batteries. However, the mechanism of the atomically dispersed dual metal atom with the coordination of various heteroatoms used as the sulfur cathode catalyst and trapper remains unknown. This study introduces, for the first time, atomically dispersed Co and Mn in-situ immobilized on O, N dual-doped hollow carbon spheres (SACoMn/C-(N, O)) as sulfur host. Experiments combined with density functional theory calculations reveal that the synergy between Co-(N, O) and Mn-(N, O) sites enhances the nucleation/deposition and decomposition capabilities of Li2S. This enhancement is attributed to the anchoring-coupling-conversion behavior of sulfur species on the SACoMn/C-(N, O) surface, which effectively restrains the shuttle effect and facilitates the conversion kinetics. Moreover, the cooperation of dual metal atoms with O, N non-metal atoms embedded in the carbon network structure accelerates electric transport and ion diffusion kinetics. The cathode demonstrates a high initial specific capacity of 890 mAh·g−1 at 1 C and show exceptional long-term cycling durability, with a low capacity degradation of 0.037 % per cycle after 1700 cycles. This research may offer novel insights into the design of dual metal atom-decorated, functionalized carbon materials to improve the conversion reaction in sulfur cathodes.

Marine waste derived carbon materials for use as sulfur hosts for Lithium-Sulfur batteries

Lithium–sulfur batteries are a promising alternative to lithium-ion batteries as they can potentially offer significantly increased capacities and energy densities. The ever-increasing global battery market demonstrates that there will be an ongoing demand for cost effective battery electrode materials. Materials derived from waste products can simultaneously address two of the greatest challenges of today, i.e., waste management and the requirement to develop sustainable materials. In this study, we detail the carbonisation of gelatin from blue shark and chitin from prawns, both of which are currently considered as waste biproducts of the seafood industry. The chemical and physical properties of the resulting carbons are compared through a correlation of results from structural characterisation techniques, including electron imaging, X-ray diffraction, Raman spectroscopy and nitrogen gas adsorption. We investigated the application of the resulting carbons as sulfur-hosting electrode materials for use in lithium–sulfur batteries. Through comprehensive electrochemical characterisation, we demonstrate that value added porous carbons, derived from marine waste are promising electrode materials for lithium–sulfur batteries. Both samples demonstrated impressive capacity retention when galvanostatically cycled at a rate of C/5 for 500 cycles. This study highlights the importance of looking towards waste products as sustainable feeds for battery material production.

Dynamically regulated redox shuttling and nucleation of lithium polysulfides through the built-in ferroelectric field

Sulfur is highly desired for energy storage devices by virtue of its high theoretical specific capacity and natural abundance. Yet the lithium-sulfur battery becomes practically unstable due to the migration of lithium polysulfides (LiPSs), which is the major challenge for its widespread application. Here, we demonstrate that the polysulfide redox shuttling can be kinetically buffered, which relies on a rational design of ferroelectric/carbon interfaces in a silica-based host structure. In situ TEM observation shows that a robust sulfur host is constructed by spatially embedding ferroelectric BaTiO3 nanodots within both the shell and bulk of a yolk-shell microsphere. During the electrochemical cycling process, the as-prepared composite material functions as a LiPSs pocket. It facilitates the reversible LiPSs conversion, giving rise to long-term stabilization of lithium-sulfur battery. This is due to the synergetic effect of the built-in polarization electric field and abundant LiPSs nucleation sites at internal ferroelectric/carbon interfaces. Furthermore, we show that the nucleation and growth of Li2Sn can be regulated by the designed polarization electric field in the yolk-shell structure. This study further highlights the potential of physical field towards high-performance lithium-slfur batteries.

Tube‐in‐Tube Structure Design and In‐situ Growth of Fe3C for Efficient Reaction Kinetics in Lithium‐Sulfur Batteries

AbstractTo improve the sulfur reaction kinetics and inhibit the notorious shuttle effects, a tube‐in‐tube structure decorated by carbon nanotubes (CNT) and Fe3C nanoparticles (TIT/Fe3C‐CNT) is designed as sulfur host for lithium‐sulfur batteries (LSBs) in this work. The construction of tube‐in‐tube structure increases the active sites and the specific surface area of the material. Additionally, Fe3C nanoparticles can effectively adsorb the soluble lithium polysulfides and promote their catalytic conversion, thus greatly alleviating the shuttle effects. As a result of these advantages, the TIT/Fe3C‐CNT‐based cathode exhibits a high reversible capacity of 841 mAh g−1 after 200 cycles with a low decay of 0.056 % per cycle at 0.5 C. This work provides a promising and reasonable approach to the rational design of sulfur host for LSBs.

Partially oxidized Ti3–yNbyC2Tx MXene nanosheets as efficient sulfur hosts and separator modification for Li–S batteries

Partially oxidized Ti3–yNbyC2Tx MXene nanosheets as efficient sulfur hosts and separator modification for Li–S batteries