Sulfur Host Research Articles

B, N co-doped 3D hierarchical porous carbon entrapping sulfur for high performance of Li-S batteries

The dissolution and diffusion of polysulfide compounds in lithium-sulfur (Li-S) batteries restrict their cyclic stability. The sulfur hosts are the key to achieve good cyclic stability for Li-S batteries. Here, a three-dimensional hierarchical heteroatoms B, N-doped porous carbon (BNC) was prepared as a new sulfur host. The active sulfur can be anchored inside the cathode due to the incorporation of atomic functional groups formed by B and N co-doping, which enhances the adsorption capacity between the cathode and lithium polysulfides. The resulting BNC loaded sulfur (S@BNC) cathode exhibits high specific capacity and electrochemical stability. Specifically, the reversible specific capacity of S@BNC cathode achieved a reversible specific capacity of 1056.8 mAh g−1 at 0.1 C. After 500 cycles, the specific capacity still remains 618.5 mAh g−1 at 0.2 C, which corresponds to a capacity decay rate of 0.0776 %. The results suggest that BNC has great potential as the sulfur host for achieving high performance of Li-S batteries.

Rhizopus Hyphae Carbon as Efficient Sulfur Host For Lithium–Sulfur Batteries

Rhizopus Hyphae Carbon as Efficient Sulfur Host For Lithium–Sulfur Batteries

A Review of Electrospun Carbon-Based Nanofibers Materials used in Lithium-Sulfur Batteries.

Commercial lithium-ion batteries are gradually approaching their theoretical specific energy, which cannot meet the fast-growing energy storage demands. Lithium-sulfur (Li-S) batteries are anticipated to supersede lithium-ion batteries as the next-generation energy storage system owing to their high atheoretical specific capacity (1675 mAh g-1) and energy density (2600 Wh kg-1). Nonetheless, Li-S batteries encounter several challenges, including the inadequate conductivity of sulfur and lithium sulfide, sulfur's volume expansion, and the shuttle effect of lithium polysulfides, all of which significantly impact the practical utilization of Li-S batteries. Electrospun carbon-based nanofibers can simultaneously resolve these issues with their economical preparation, distinctive nanostructure, and exceptional flexibility. This review presents the most recent research findings on electrospun carbon-based nanofibers materials serving as sulfur hosts and interlayer components in Li-S batteries. We analyzed the impact of the material's structural design on the performance of Li-S batteries and the relative underlying mechanism. Finally, the current challenges and issues faced by carbon-based nanofibers composites in the application of Li-S batteries are summarized, and the future development trajectory are outlined.

Ultrafast microwave synthesis of MoSSe@ graphene composites via dual anion design for long-cyclable Li-S batteries

Lithium-sulfur batteries (LSBs) have been increasingly recognized as a promising candidate for the next-generation energy-storage systems. This is primarily because LSBs demonstrate an unparalleled theoretical capacity and energy density far exceeding conventional lithium-ion batteries. However, the sluggish redox kinetics and formidable dissolution of polysulfides lead to poor sulfur utilization, serious polarization issues, and cyclic instability. Herein, sulfiphilic few-layer MoSSe nanoflake decorated on graphene (MoSSe@graphene), a two-dimensional and catalytically active hetero-structure composite, was prepared through a facile microwave method, which was used as a conceptually new sulfur host and served as an interfacial kinetic accelerator for LSBs. Specifically, this sulfiphilic MoSSe nanoflake not only strongly interacts with soluble polysulfides but also dynamically promotes polysulfide redox reactions. In addition, the 2D graphene nanosheets can provide an extra physical barrier to mitigate the diffusion of lithium polysulfides and enable much more uniform sulfur distribution, thus dramatically inhibiting polysulfides shuttling meanwhile accelerating sulfur conversion reactions. As a result, the cells with MoSSe@graphene nanohybrid achieved a superior rate performance (1091 mAh/g at 1C) and an ultralow decaying rate of 0.040 % per cycle after 1000 cycles at 1C.

Nickle-doped covalent organic frameworks/carbon nanotubes composite for high-performance lithium-sulfur batteries

Lithium-sulfur batteries (LSBs) are considered as one of the most promising next-generation energy storage systems. To mitigate the shuttle effect of lithium polysulfides (LiPSs) in LSBs, the rational design of sulfur hosts with high physical confinement and catalytic activity is critical to enhance the performance of LSBs. Here, we successfully prepare a nickle-doped covalent organic frameworks/carbon nanotubes composite (Ni/COFs/CNTs) as the sulfur host in LSBs. COFs can confine and immobilize sulfur species. Moreover, CNTs and Ni nanoparticles can provide fastelectrontransferpathways. Thus, Ni/COFs/CNTs composite can alleviate the shuttle effect during the cycling processes.The S/Ni/COFs/CNTs cathode displays a high initial reversible capacity of 1068.6 mAh g−1 and a high capacity retention (83.3 %) after 100 cycles at 0.1C. This work provides a useful strategy to the rational design of sulfur hosts for LSBs.

Remarkable chemical adsorption and catalysis of 3D self-supporting Zn-doped NiCo2O4 nanowires for high-performance lithium-sulfur batteries

Lithium-sulfur batteries are one of the most potential next-generation energy storage systems with high theoretical energy density and low cost. However, the lithium polysulfides (LiPSs) dissolution and shuttle effect limit their commercial application. Herein, the Zn-doped NiCo2O4 nanowires grown on carbon cloth (ZNCOCC) are prepared by hydrothermal method and as sulfur host. ZNCO nanowires consisting of stacked nanoparticles and abundant mesopores were grown vertically on carbon fibers. The mesoporous structure of ZNCOCC provides more space to accommodate sulfur and its volume change during charging and discharging, is conducive to electrolyte infiltration and maintains strong adsorption of LiPSs to ensure fast ion transport kinetics. The ZNCOCC displays higher Co3+/Co2+ and Ni3+/Ni2+ ratio compared to NCOCC, and the high-valent metal cations can provide more unsaturated electron orbitals for S binding, causing high adsorption of LiPSs. Density functional theory calculations demonstrate that the Zn doping significantly reduces the band gap, improves the conductivity and increases the LiPSs adsorption energy of NCO. The ZNCOCC/Li2S8 displays a high specific capacity of 1184 mAh g−1 (0.1 C) and a low decay of 0.07 %/cycle after 500 cycles (2 C). This research reveals the rational design of a doped bimetal oxide nanostructure for the improvement of lithium-sulfur batteries.

3D Co-doped carbon nanosheets as high-performance electrodes for Li-S batteries

3D petal-shaped Cobalt-doped carbon nanosheets (PCoCNS) were synthesized as excellent sulfur hosts for lithium-sulfur (Li-S) batteries. Co doping enhanced the affinity of the carbon surface for lithium polysulfides (LiPSs), inhibiting the shuttle effect. The electrocatalytic effect of the PCoCNS electrode exhibited enhanced polysulfide conversion kinetics, thereby promoting Li2S formation. Owing to the above advantages, the PCoCNS cathode exhibited satisfactory reversibility of 841 mAh/g with a high capacity retention of 91 %. Additionally, it displayed high coulombic efficiency (CE) values exceeding 97 % over 100 cycles at a current rate of 0.5C. Furthermore, the electrode demonstrated low polarization and exhibited an excellent rate performance, delivering a capacity of 575 mAh/g at the high rate of 3C. This study synthesized a promising sulfur cathode for enhancing the electrochemical performance of Li-S batteries.

Scalable Ni12P5-Coated Carbon Cloth Cathode for Lithium–Sulfur Batteries

As a better alternative to lithium-ion batteries (LIBs), lithium–sulfur batteries (LSBs) stand out because of their multi-electron redox reactions and high theoretical specific capacity (1675 mA h g−1). However, the long-term stability of LSBs and their commercialization are significantly compromised by the inherently irreversible transition of soluble lithium polysulfides (LiPS) into solid short-chain S species (Li2S2 and Li2S) and the resulting substantial density change in S. To address these issues, we used activated carbon cloth (ACC) coated with Ni12P5 as a porous, conductive, and scalable sulfur host material for LSBs. ACC has the benefit of high electrical conductivity, high surface area, and a three-dimensional (3D) porous architecture, allowing for ion transport channels and void spaces for the volume expansion of S upon lithiation. Ni12P5 accelerates the breakdown of Li2S to increase the efficiency of active materials and trap soluble polysulfides. The highly effective Ni12P5 electrocatalyst supported on ACC drastically reduced the severity of the LiPS shuttle, affected the abundance of adsorption–diffusion–conversion interfaces, and demonstrated outstanding performance. Our cells achieved near theoretical capacity (>1611 mA h g−1) during initial cycling and superior capacity retention (87%) for >250 cycles following stabilization with a 0.05% decay rate per cycle at 0.2 C.

Preparation of MoSe2 nanosheets/nitrogen-doped carbon nanotubes and their electrochemical energy storage properties

Lithium-sulfur batteries can be used as excellent energy storage devices, but they still face some challenges in the practical application, such as the poor electrical conductivity of sulfur, the volume expansion of sulfur during the discharge process, and the dissolution of polysulfides. In this study, polypyrrole-coated molybdenum trioxide nanorods were used as templates for the simultaneous in-situ growth of MoSe2 nanosheets on the outer/inner sides of nitrogen-doped carbon nanotubes. When the MoSe2/N-carbon nanotubes (MoSe2/NC NTs) were used as sulfur carriers for lithium-sulfur battery, the large specific surface area of the N-carbon nanotubes facilitated the homogeneous loading of MoSe2 nanosheets and exposed more catalytically active sites of the MoSe2 nanosheets, increasing the contact area of electrolyte. In addition, the N-doped carbon nanotubes have excellent electrical conductivity, which greatly promotes the electrical conductivity of the cathode. The density functional theory calculations, adsorption experiments, and XPS results all confirm that the MoSe2/NC NTs are able to anchor lithium polysulfides through strong adsorption, thus effectively mitigating the shuttle effect of polysulfides. This study supplies a novel route for the preparation of sulfur host for advanced lithium-sulfur batteries.

Nitrogen-doped 3D carbon hybrids based on modified lignin as sulfur host for high-performance lithium-sulfur batteries

Constructing a sulfur host with strong adsorption and catalytic conversion of polysulfides is significant in improving the electrochemical performance of lithium-sulfur batteries. In this work, we obtained nitrogen-doped 3D carbon hybridized materials (lignin porous carbon/carbon nanotubes, LPC/CNTs) by self-assembly and in situ activation methods. This is the first time to achieve nitrogen-doped carbon hybrids by melamine modification lignin as raw material. The results show that the construction of the nitrogen-doped 3D carbon hybridization network is highly correlated with the modification treatment of lignin. As sulfur host material, it can reach a specific capacity of 1300.18 mAh g−1 at 0.1 C for the first time and still has a specific capacity of 582.84 mAh g−1 at 1 C for 400 cycles. In addition, carbon hybridized materials show excellent rate performance and high current adaptability in the rate performance test compared with the carbon materials prepared from unmodified lignin. The excellent electrochemical performance is mainly attributed to the synergistic effect within the 3D interconnection network, which enhances the physical confinement and chemical adsorption of polysulfides, as well as the catalytic conversion. This work provides new insights into biomass application in the sulfur hosts of lithium-sulfur batteries.

Dual-engineering of tungsten doping and carbon incorporation in vanadium carbide arrays to accelerate the polysulfide conversion for lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries are promising candidates for next-generation electrochemical energy storage systems by virtue of the high energy density, low-cost, and ecofriendliness. Unfortunately, the sluggish sulfur conversion kinetics, notorious shuttle effect of lithium polysulfides (LiPSs) and severe volumetric variation during the lithiation/delithiation process result in insufficient sulfur utilization and fast capacity degradation. Herein, tungsten-doped vanadium carbide nanosheet arrays strongly coupled with a thin nitrogen-doped carbon layer directly grown on carbon cloth substrate (denoted as CC/W-VC@NC) have been conceptually designed as an advanced sulfur host to resolve the aforementioned problems. Specifically, the binder-free CC/W-VC@NC sulfur host not only strongly interacts with LiPSs, but also presents superior electrocatalytic activity for rapid LiPSs conversion. Additionally, the arrayed architecture provides sufficient space for sulfur loading and simultaneously accommodates its volumetric variation. Furthermore, theoretical calculations elucidate that tungsten doping can regulate the electronic structure, improve the electrical conductivity and strengthen the chemisorption toward LiPSs. Attributing to the multifarious advantages, Li-S batteries assembled with CC/W-VC@NC/S cathode exhibit a high initial discharge capacity of 1305.9 mAh/g at 0.1 C, as well as superior rate capability (709.8 mAh/g at 5 C) and good long-term durability (capacity decay rate of only 0.063 % per cycle over 500 cycles at 1 C). This study presents an effective approach to construct transition metal carbides as high-performance sulfur hosts for Li-S batteries.

Nitrogen-Doped Carbon and Metal-Nitrogen-Carbon Materials as Cathode Hosts for Li-S Batteries: Experimental Study and Mechanism Analysis.

Both nitrogen-doped carbon (NC) and metal-nitrogen-carbon (MNC) materials have been extensively investigated in lithium-sulfur batteries to alleviate the "shuttle effect". MNC are generally synthesized using NC as the parent material, wherein nitrogen atoms in NC serve as the "bridge" to coordinate with metal atoms. So far, an important scientific issue has not been settled: does the introduction of metal sites into NC certainly enhance the Li-S battery performance? In this work, NC and MNC materials derived from the same precursor, a nitrogen-rich porous polymer, are systematically compared as cathode hosts for Li-S battery through theoretical calculations and experimental investigation. Li-S cell with NC as the cathode sulfur host exhibits better cycle performance at low current densities (0.1 and 0.2C), whereas MNC materials predominate at higher current densities (such as 1C and 2C). Based on theoretical calculation and experimental results, it is concluded that the introduction of metal sites into NC through nitrogen bonding promoted the catalytic capability for faster sulfur redox reaction kinetics, whereas the adsorption energy toward polysulfides decreased. This work provides important guidance for more targeted design of advanced materials for lithium-sulfur battery application in the future.

FeF3·0.33H2O nanoparticles decorated Ti3C2 MXene as high-performance bifunctional sulfur host for lithium‑sulfur batteries

Lithium‑sulfur batteries are deemed as a potential next-generation energy storage system, but their development is hindered by the shuttle effect of lithium polysulfides. Design and synthesis of multifunctional sulfur host materials are expected to adsorb lithium polysulfides and catalyze their conversion during the lithiation process, thereby suppressing the shuttle effect. In this work, FeF3·0.33H2O nanoparticles is in situ grown on the surface of Ti3C2 nanosheets (FeF3@Ti3C2) and used as the bifunctional sulfur host for lithium‑sulfur batteries. Ti3C2 nanosheets not only provide two-dimensional (2D) conductive substrate for sulfur, but also strongly adsorb lithium polysulfides and suppress the shuttle effect. Meanwhile, FeF3 nanoparticles can accelerate the conversion reaction of lithium polysulfides, which also contributes to inhibiting the shuttle of lithium polysulfides. In addition, decorating Ti3C2 nanosheets with FeF3 nanoparticles can prevent the stacking of Ti3C2 nanosheets and enhance the interaction between Ti3C2 and lithium polysulfides. Therefore, sulfur-loaded FeF3@Ti3C2 (FeF3@Ti3C2@S) displays excellent electrochemical performance, such as a high reversible capacity of 687 mAh g−1 at 2C after 1000 cycles, and the capacity decay rate is only 0.023 %. This work paves a simple way for improving the performance of Ti3C2 as the sulfur host and expanding its application in lithium‑sulfur batteries.

Chitosan-derived N-doped porous carbon with fiber network structure for advanced lithium‑sulfur batteries

The flexible design and construction of advanced carbon-based sulfur hosts contribute to the rapid redox and reaction kinetics of lithium polysulfides (LiPSs) in lithium‑sulfur batteries (LSBs), laying the foundation for the next generation of high-energy density energy storage devices. Herein, chitosan (CS)-derived porous N-doped carbon with fiber network structure was prepared by a simple freeze-drying method combined with sintering process. The effect of inorganic salt additives on the morphology of CS-derived carbon was investigated by SEM. The types and contents of N-doping were investigated through XPS analysis. The influence of morphology and N content on the performance of LSBs has been explored in detail through cycling and CV testing. In addition, the true active sites in the CS-derived carbon were determined by XPS and first principles calculations. As an active species, pyrrolic N exhibits superior adsorption energy and the most suitable degradation energy barrier for LiPSs. As the optimal electrode, the performance of LSBs under different electrolyte to sulfur (E/S) conditions was further investigated to explore the potential application of CS-KOH electrodes in high-energy density batteries. The results unveil that the influence of E/S on Li2S deposition is quite significant, with a limit of 5 μL mg−1. This work provides a new strategy for the preparation of high-performance advanced carbon-based materials with fiber network structures from polysaccharide biomass, and also promotes the application of CS in energy storage.

A nanoflower structure rare-earth La3+ doping Sn3O4 with highly catalytic active interfaces as a sulfur host facilitates the conversion kinetics of polysulfides in high-performance lithium-sulfur batteries

Lithium-sulfur batteries are considered a favourable contender for next-generation energy storage systems owing to their high energy density (2600 Wh·kg−1). However, the severe "shuttle effect" of polysulfides and the slow redox kinetics involving phase transitions have seriously limited the commercialization of lithium-sulfur batteries. On this basis, in this paper, a type of nanoflower structure rare-earth lanthanum ion (La3+) doping Sn3O4 with a large number of catalytic active interfaces is designed via a facile one-step hydrothermal method. When serves as a capture centre to immobilize polysulfides, it exhibits a strong chemical adsorption capacity. Moreover, due to the unique 4 f electron configuration of the rare-earth elements, nanoflower structure La3+ doping Sn3O4 (La@Sn3O4) as sulfur-wrapped matrix has a strong catalytic activity, which can effectively accelerate the conversion process of polysulfides. At the same time, the catalytic mechanism of La@Sn3O4/S composite cathode material targeting the solid to liquid phase transformation of polysulfides is effectively revealed via in-situ Raman spectroscopy test and the initial discharge capacity can reach 1429.6 mAh·g−1 at a current density of 0.1 C, and the capacity retention rate is 76.5 % after 130 cycles.

Single-atom decorated hollow mesoporous carbon spheres composited with free-standing carbon cloth supported cobalt sulfide nanowire arrays as high-performance sulfur host for lithium-sulfur batteries

BackgroundLithium-sulfur batteries (LSBs) are a promising next generation electrochemical energy storage device. Its commercialization however is hindered by several technical challenges, particularly shuttling of polysulfides. MethodsA composite sulfur host, coupled with a porous current collector, was developed to mitigate the shuttling problem. Iron single atom (SAFe) decorated hollow mesoporous carbon spheres (HMCS), composited with cobalt sulfide nanowire arrays supported on free-standing carbon cloth (S-Co@CC), were fabricated as a high-performance sulfur host for LSBs. The sulfur host combines the high electrical conductivity and physical confinement capability of HMCS, the excellent polysulfides chemisorption capability of cobalt sulfide nanowire arrays, and the high catalytic efficiency of iron single atoms toward polysulfide conversion reactions, to achieve a high-performance LSB. Significant findingsThe S-Co@CC/SAFe-HMCS based LSB exhibited a high initial specific capacity of 1430 mAh g−1 at 0.1 C. For cycling stability, a specific capacity of 578 mAh g−1 was maintained after a 600-cycle operation at 1 C, achieving an ultralow average capacity decay rate of 0.029 % per cycle. The design of composite sulfur hosts, combining all functional components in one, proves to be an effective strategy to advance the development of high-performance LSBs.

Synthesis of Nixp/C Nanofibers As Interlayer and Sulfur Host for Lithium-Sulfur Batteries

Lithium-sulfur batteries (LSB) have a high theoretical capacity (1675 mAh g − 1) and energy density (2600 Wh kg−1), making them one of the most promising energy storage systems. 1 However, it has some limitations, such as “shuttle effect” of polysulfides and high volume expansion, causing poor cycle performance of the battery.The transition metal phosphides with carbon materials as sulfur host for LSB have attracted extensive scientific focus due to the large surface area and strong chemisorption ability. Moreover, high electrical conductivity of carbon-based material and the chemical adsorption effect of Ni-P phase can reduce the “shuttle effect”, and improve the cyclability of the material. 2,3 In this work, nickel phosphide carbon composite (NixP/C) nanofibers were synthesized using a water-soluble carbon source polyvinylpyrrolidone (PVP) and cost-effective electrospinning method. The impact of humidity on the physical and electrochemical characteristics of the electrospun NixP/C nanofibers was studied, utilizing them as interlayer and sulfur host material for LSB.The NixP/C nanofibers were synthesized using an electrospinning machine from PVP, nickel nitrate hexahydrate, and phosphoric acid as precursors. The nanofibers were electrospun at 18 kV voltage and 0.8 mL h–1 flow rate. The electrospinning humidity (RH) varied between 19-35%. Obtained nanofibers were dried at 110 ºC for 11 h. Finally, prepared fibers were annealed at 700 ºC for 1 h with a heating rate of 5 ºC min-1 in the N2 + H2 (4%) atmosphere.The crystalline phases of the final products were observed using X-Ray diffraction (XRD, Miniflex, Rigaku). The microstructure was studied by transmission electron microscopy (TEM, JEM-1400 Plus, JEOL). According to the results shown in Figure 1, Ni2P with a hexagonal structure and the space group of P62m, and Ni12P5 with a tetragonal structure, space group of 87:I4/m were formed. Nanoparticles of NixP are uniformly distributed within the carbon fiber matrix (inset).The NixP/C freestanding mats were embedded as a sulfur host or interlayer for LSB in CR2032 coin-type cells. 1 M Li2S6 catholyte solution and 1 M LiTFSI in 1,3- dioxolane (DOL)/1,2 dimethoxyethane (DME) (v/v, 1:1) with 2 wt% of LiNO3 were used as a source of sulfur and electrolyte, respectively. Further details and obtained results will be presented at the conference. Acknowledgements This research was funded by the projects AP13068219 “Development of multifunctional free-standing carbon composite nanofiber mats”, and AP19675260 “Development of nanofibrous electrode materials for next-generation lithium-ion batteries” from the Ministry of Education and Science of the Republic of Kazakhstan.

Pyrene Funtionlized Hollow Porous Carbon/S-Dib Composite As a Cathode for Lithium-Sulfur Batteries

Lithium-sulfur batteries (LiSBs) stand out as promising candidates for the next-generation energy storage system. However, challenges such as the “shuttling effects” of intermediate lithium polysulfides and sluggish conversion between sulfur and lithium sulfide have led to low specific capacity under high current and a shortened cycling life for LiSBs. Extensive research has explored porous carbon materials as hosts for sulfur in LiSBs cathodes. Nevertheless, overcoming the “shuttling effects” and ensuring the uniform deposition of lithium sulfide without using metals or metal-containing species remains a challenge.Taking advantage of its aromatic properties, which promotes robust π-π interactions with sp2-hybridized carbon, pyrene with various functionalized groups emerges as a viable solution for surface modification through non-covalent bonding to carbon. In this study, we present the synthesis of X-pyrene (X=OH, NH2, Cl) modified hollow porous carbon (HPC) serving as a micro-reactor for inverse vulcanization, resulting in the formation of S-DIB/X-HPC (X=OH, NH2, Cl) with a uniform structure. Abundant oxygen-, nitrogen- and chloride interfaces were designed to act as adsorption catalytic sites, accelerating conversion kinetics and mitigating shuttle effects.Hollow porous carbon (HPC) nanoparticles were prepared from ZIF-8 by carbonization at 950 °C under argon atmosphere. (Figure 1a). The cross-sectional view in Figure 1b reveals numerous individual hexagonal structures with abundant internal pores. This structure helps accommodate inverse vulcanization (IV) reactions and ensures the uniform distribution of the final product (S-DIB). To evaluate the adsorption quantity of pyrene on the carbon surface, standard solutions of varying pyrene concentrations in dimethyl sulfoxide (DMSO) were prepared and analyzed using Ultraviolet–visible spectroscopy (UV-VIS). A linear relationship is fitted between the intensity of these peaks with the standard pyrene solution. Therefore, the concentration in the filtrate is verified to be approximately 2 mM, in contrast to the initial concentration of 10 mM before adsorption. This observed concentration decrease implies an effective adsorption of pyrene molecules onto the HPC surface. To further investigate the catalytic effect of Cl-pyrene and NH2-pyrene for sulfur redox reactions, potentiostatic nucleation of Li2S on the HPC, Cl-HPC and NH2-HPC electrodes were conducted to clarify the involved multiphase transition process. As shown in Figure 3, the capacity of precipitated Li2S on Cl-HPC (160.62 mAh gS −1) and NH2-HPC (135.75 mAh gS −1) are both higher than that on HPC (99. 93 mAh gS −1). As a result, superior to S-DIB/HPC, the S-DIB/Cl-HPC cathode exhibits a higher initial specific capacity of 1208 mA h g−1 at 0.1 C and a capacity of 643 mA h g−1 at 3 C, and still retain 913 mAh g−1 while returning to 0.1 C. Furthermore, the S-DIB/NH2-HPC cathode possesses excellent cyclability with a high capacity retention of 652 mAh g−1 at 1 C over 300 cycles, yielding an average capacity decline of only 0.076% per cycle. Additionally, we investigate the impact of native surface groups on the deposition of lithium sulfide and the conversion of polysulfides. Figure 1

The Impact of Biomass-Derived Graphene-like Porous Carbon Decorated with NiO Nanoparticles on the Electrochemical Performance of Lithium-Sulfur Batteries

Lithium-sulfur batteries are considered a promising next-generation energy storage system, boasting high theoretical capacity and energy density, approximately double that of LiBs [1,2]. However, challenges such as low sulfur conductivity, significant volume expansion during cycling, and the lithium polysulfides shuttle effect hinder their practical use [3]. These issues result in side reactions, irreversible loss of active material, and anode degradation, leading to a rapid decline in cell capacity stability [4].In this research, we successfully developed a sulfur cathode carbon matrix and separator modifier from rice husk through carbonization and thermal activation. The resulting graphene-like porous carbon (GPC) exhibited high efficiency as a sulfur host, enhancing the electrochemical performance of the cathode. The GPC-NiO composite also served effectively as a separator modifier, catalyzing lithium polysulfides' redox reactions and improving the overall cycling stability of lithium-sulfur batteries. In particular, the GPC@S/GPC-NiO-20 cell demonstrated an excellent initial discharge capacity of 1519 mAh g-1 at 0.2 C. Also, it delivered excellent long-term cycling, maintaining a discharge capacity of 661 mAh g-1 even after 400 cycles at 1 C, with a Coulombic efficiency exceeding 97%. It exhibited a promising rate capability of 568 mAh g-1 at 2 C and retained a discharge capacity of 603 mAh g-1 over 100 cycles at 0.2 C with a sulfur loading of 4.0 mg cm-2. Acknowledgments This research is funded by the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan (Grant No. AP19677708).

Dopamine Functionalized TiO2 1D Lepidocrocite Mesoporous Particles As a Sulfur Host

Lithium sulfur batteries are attractive because of their high specific capacities. However, a variety of issues, chiefly polysulfides and the polysulfide shuttle still hinder their development. In our past work we demonstrated a new form of titania-based nanomaterials which we labelled 1 dimensional lepidocrocite nanofilaments (1DLs) as a sulfur (S) host for Li-S batteries1. 1DL is synthesized using a facile bottom-up scalable reaction, directly from commercial 3D bulk solids at ambient pressures and near ambient temperatures2. Moreover, these materials self-assemble into a plethora of microstructures – from individual 1D nanofilaments 5x7 Å2 in cross-section to 2D flakes to mesoscopic particles, all comprised of 1DL - depending on the synthesis and washing parameters. The multitude of structures allows for a variety of applications like electrocatalysis and hydrogen production3. Here we introduce a new structure of 1DLs - mesoporous particles - as S hosts. We further show that by employing a facile, aqueous, 1-step surface functionalization with dopamine – confirmed through changes in the FTIR peaks and an increase in the d-spacing in XRD (inst in Fig 1b) – we increase their interaction with S. The surface functionalization results in a reduction of the 1DL bandgap energy, Eg, to ~1.84 eV, which is a ≈ 50% reduction over un-functionalized 1DL. Additionally, the surface functionalization renders a more conformal coating of S on the 1DL, leading to increased S utilization and interaction with the 1DL, seen in a 20% reduction in of polysulfide shuttle current and 750 mAh.gs -1 at 0.5 C at a loading of 2 mg.cm-2 (seen in Fig 1a and 1b). This is further seen in the increased interactions of the thiosulfate species and Lewis acid-base interactions, shown in our prior work with S and 1DL.References Cardoza, N. A.; Badr, H. O.; Pereira, R.; Barsoum, M. W.; Kalra, V. One-Dimensional, Titania Lepidocrocite-Based Nanofilaments and Their Polysulfide Anchoring Capabilities in Lithium–Sulfur Batteries. ACS Appl. Mater. Interfaces 2023, 15 (44), 50973–50980.Badr, H. O.; Cope, J.; Kono, T.; Torita, T.; Lagunas, F.; Castiel, E.; Klie, R. F.; Barsoum, M. W. Titanium Oxide-Based 1D Nanofilaments, 2D Sheets, and Mesoporous Particles: Synthesis, Characterization, and Ion Intercalation. Matter 2023, 6 (10), 3538–3554.Badr, H. O.; Natu, V.; Neațu, Ștefan; Neațu, F.; Kuncser, A.; Rostas, A. M.; Racey, M.; Barsoum, M. W.; Florea, M. Photo-Stable, 1D-Nanofilaments TiO2-Based Lepidocrocite for Photocatalytic Hydrogen Production in Water-Methanol Mixtures. Matter 2023, 6 (9), 2853–2869. Figure 1