Sulfur Host For Lithium-sulfur Batteries Research Articles

Tubular C3N4 Nanotubes as Metal-Free Sulfur Hosts toward Stable Lithium–Sulfur Batteries

Lithium–sulfur batteries (LSBs) with high energy density have the potential to replace current commercial lithium-ion batteries. However, the shuttle effect and the low conversion kinetics of lithium polysulfide (LiPS) remain the main challenges in the development of LSBs. In this study, a metal-free and simple-to-prepare carbon nitride with a high surface area and tubular morphology (CN-nt) is used as the sulfur host for LSBs. Due to its unique nanostructure and rich active sites, it not only effectively disperses the active sulfur material and anchors soluble polysulfide species, but it also promotes the nucleation process of Li2S, thus achieving fast and sustainable Li-S redox reactions. Experimental results show that the obtained S@CN-nt electrodes exhibit a high sulfur utilization of 1296.2 mAh g−1 at 0.1 C and a significant rate capability of 689.4 mAh g−1 at the high current rate of 3C. More importantly, the capacity retention reaches 87.7% after 500 cycles. This simple strategy of engineering unique carbon-based nanostructured hosts can inspire new ideas for developing cost-effective and metal-free host materials for sulfur-based batteries.

Electrospun CuCoN0.6 coating necklace-like N-doped carbon nanofibers for high performance lithium-sulfur batteries

Freestanding electrodes with high energy density and cycle stability have attracted attention on the development of lithium-sulfur (Li-S) batteries. However, both severe shuttle effect and sluggish conversion kinetics hinder their practical applications. Herein, we employed the electrospinning and subsequent nitridation processes to prepare a necklace-like structure of CuCoN0.6 nanoparticles anchored on N-doped carbon nanofibers (CuCoN0.6/NC) as freestanding sulfur host for Li-S batteries. Such bimetallic nitride boosts chemical adsorption and catalytic activity throughout detailed theoretical calculation and experimental electrochemical characterization. The three-dimensional conductive necklace-like framework could provide abundant cavities for realizing high sulfur utilization and alleviating the volume variation, as well as fast lithium-ions diffusion and electron transfer. The Li-S cell with the S@CuCoN0.6/NC cathode delivers a stable cycling performance with a capacity attenuation rate of 0.076% per cycle after 150cycles at 2.0C and an exceptional capacity retention of 657 mAh g−1 even at a high sulfur loading of 6.8 mg cm−2 over 100cycles. The facile and scalable method can help promote the widespread application of fabrics.

Hollow carbon dual-decorated with MnO2 shielding layer and carbon nanotube as a sulfur host for Li-S batteries

The shuttle effect of polysulfides and sluggish reaction kinetics have been the main obstacles for the practical applications of lithium-sulfur (Li-S) batteries. Herein, we report a rationally designed sulfur cathode (DLHC/S@MnO2-ACNT) based on double-layered hollow carbon sphere (DLHC) decorated with manganese dioxide (MnO2) shielding layer and carbon nanotube conductive network (ACNT). The Ultramicrotome technique demonstrates that S and MnO2 nanosheets are mainly located into the interlayer of the DLHC. In the elaborate nanostructured protocol, the interlayer MnO2 nanosheets catalyze the conversion of polysulfides and the surface MnO2 nanosheets effectively adsorb polysulfides to suppress the shuttle effect. Additionally, the ACNT conductive network facilitates electrons/ions transport. Benefiting from the hierarchical confinement, Li-S batteries with DLHC/S@MnO2-ACNT composite cathodes exhibit a high reversible capacity of 1051 mAh g−1 at 0.5 C and a remarkable cycling stability over 500 cycles at 1 C. Even at a high sulfur loading of 4 mg cm−2, the cell delivers a superior areal capacity of 4.47 mAh cm−2. This work provides a new route to the design of hierarchical confinement sulfur hosts for high-performance Li-S batteries.

Encapsulation of sulfur inside micro-nano carbon/molybdenum carbide by in-situ chemical transformation for high-performance Li-S batteries

AbstractIn lithium-sulfur (Li-S) batteries, the electrochemical properties of the sulfur cathode are determined by the sulfur host, and this controls the shuttle effect and the kinetics, two of the major problems in these batteries. We confined the S in hollow thin-wall C/Mo2C particles smaller than 7 nm across that clustered together to form micrometer-size particles. The conducting network of C/Mo2C shells facilitates lithium-ion and electron transport while acting as a barrier to the outward diffusion of polysulfides. They also improve the redox kinetics because of the catalytic conversion of polysulfides to sulfur. As a result of these features the material achieved a high reversible capacity of 1 210 mAh g−1 at 0.5 C with a low capacity fade rate of 0.127% per cycle over 300 cycles and a high rate performance (780 mAh g−1 at 3.0 C). It is expected that this work will help in the design of sulfur hosts for Li-S batteries with a high rate performance and high cycling stability.

Bio-mass derived hierarchically porous and high surface area carbon as an efficient sulfur host for lithium-sulfur batteries

Lithium–sulfur (Li-S) batteries are attractive candidates for electric vehicles and grid storage applications due to their high energy density than Li-ion batteries. Development of high energy Li-S batteries employing eco-friendly, and bio-waste derived materials will further increase the sustainability of the energy storage devices. Herein, we utilize porous carbon derived from waste watermelon rind for Li-S battery application. The porous carbon with hierarchal architecture, and functional heteroatoms can efficiently infiltrate the sulfur cathode and overcomes the major challenges in the Li-S battery, namely (i) poor electronic conductivity of sulfur cathode, and (ii) dissolution of long-chain polysulfides. The Li-S cell with a sulfur-infiltrated porous carbon delivered a high initial discharge capacity of 1176 mAh g−1 at 0.5C rate with a low capacity fading rate of 0.057% over 500 cycles. The strong carbon framework can accommodate the volume changes during the sulfur conversion reaction, and the unoccupied pores in porous carbon can function as polysulfide reservoir to efficiently trap polysulfide migration to achieve a high stability. The highly inter-connected hierarchical pores further facilitated a faster electronic and ionic transport to achieve a high rate performance, higher than pristine sulfur cathode. These results demonstrate the potential to develop high-performance energy storage devices using eco-friendly and renewable materials for electric vehicles and other energy storage systems.

Layered double hydroxides used as the sulfur hosts for lithium-sulfur batteries and the influence of metal composition on their performance

Layered double hydroxides used as the sulfur hosts for lithium-sulfur batteries and the influence of metal composition on their performance

Hierarchical carbon hollow nanospheres coupled with ultra-small molybdenum carbide as sulfiphilic sulfur hosts for lithium-sulfur batteries.

Lithium-sulfur (Li-S) batteries are an attractive candidate to replace the current state-of-the-art lithium-ion batteries due to their promising theoretical capacity of 1675 mA h g-1 and energy density of 2500 W h kg-1. However, the lithium polysulfide (LiPS) shuttle effect and the slow sulfur redox kinetics seriously decrease the utilization of sulfur and deteriorate battery performance. Here, hierarchical carbon hollow nanospheres containing intimately coupled molybdenum carbide nanocrystals were synthesized as a sulfiphilic sulfur host. The sufficient interior void space accommodates the sulfur and physically confines LiPSs, while the in situ introduced molybdenum carbide nanoparticles can chemically immobilize LiPSs and catalytically accelerate their redox transformations. As a result, the Li-S batteries with this synergistic effect achieve an excellent rate capability of 566 mA h g-1 at 2C and a long cycle stability over 300 cycles at 1C.

Sulfur-deficient MoS2-carbon hollow nanospheres for synergistic trapping and electrocatalytic conversion of polysulfides.

Lithium-sulfur battery is one of the most promising candidates for next-generation energy storage systems, but the serious shuttle effect and sluggish reaction kinetics of polysulfides impair its practical applications. Herein, sulfur-deficient MoS2/carbon hollow nanospheres (MoS2-CHNs) are firstly synthesized by a NaCl-template pyrolysis and employed as sulfur host for lithium-sulfur batteries. TEM analysis reveals that carbon hollow nanospheres existing in the composite are the backbones that help to immobilize the ultrathin MoS2 nanosheets and ensure their large specific surface area. The MoS2 nanosheets consist of 5-10 layers of MoS2 with rich sulfur vacancies. The first principle calculation demonstrates that sulfur vacancy led to an intensively enhanced binding energy (-4.70eV) towards Li2S6 compared to the pristine MoS2 (-1.57eV). It suppressed the shuttle effect efficiently. The catalytic experiments reveal that MoS2-CHNs have a superior ability for the nucleation of Li2S and bidirectional electrocatalytic capability for the conversion of polysulfide. The large storage space inside MoS2-CHNs can work as a reservoir for intermediate polysulfides to substantially reduce the concentration overpotential. Due to this advantageous structural design of MoS2-CHNs electrode, its reversible capacity remains 1139 mAh g-1 after 100 cycles at 0.2C, and 600 mAh g-1 after 500 cycles at 5C with a sulfur loading of 5mgcm-2. Even though the sulfur loading increases to 10mgcm-2, the Li-S battery delivers a stable capacity of 978 mAh g-1 after 50 cycles at 0.2C. So the MoS2-CHNs demonstrate a promising application for high-energy Li-S batteries.

Porosity vs carbon shell number: Key factor actually affecting the performance of multi-shelled hollow carbon nanospheres in Li-S batteries

• The pores in the carbon shells of HCNs play a key role in the Li + diffusion and Li 2 S x confinement. • Simply increasing the shell number in HCNs can not effectively confine the leakage of Li 2 S x from the S cathode. • Porous 1S-HCNs endow the S cathode with better cycling stability and rate capability than the oligoporous 2S-HCNs and 3S-HCNs do. • After 700 cycles, a capacity of 759 mAh g -1 with 63% retention is achieved for the S@1S-HCNs cathode at 0.2 C. As a type of sulfur host for lithium-sulfur batteries (LSBs), hollow carbon nanospheres (HCNs) are of particular interest due to their high electrical conductivity, available cavities, and unique morphology. However, there is a lack of in-depth study about the pivotal factors affecting their performance in LSBs. Herein, a series of multi-shelled HCNs have been prepared by a template-free method and the corresponding sulfur cathodes have been systematically investigated. A positive dependence of electrochemical properties on the specific surface area and pore volume of HCNs is confirmed. In case of low porosity of carbon shell, increasing the shell numbers in HCNs could not accelerate the Li + diffusion and restrict the dissolution of lithium polysulfide in the S@HCNs cathode. As a result, the highly porous 1S-HCNs endow the sulfur cathode with better cycling stability and rate performance than the oligoporous 2S-HCNs and 3S-HCNs do. This work may not only provide a useful reference in the design of novel sulfur hosts but also shed a light on the understanding of the complicated mechanism behind the sulfur redox reactions.

Kinetic Acceleration of Lithium Polysulfide Conversion via a Copper-Iridium Alloying Catalytic Strategy in Li-S Batteries.

To solve the shuttle effect of soluble lithium polysulfides (LiPSs), a porous N-doped carbon-supported copper-iridium alloy catalyst composite (CuIr/NC) has been synthesized and served as a modified cathode sulfur host for lithium-sulfur batteries (LSBs). The metal-organic framework-derived calcined carbon frameworks build efficient conductive channels for fast ion/electron transport. Furthermore, alloying noble metals Ir with thiophilic metal Cu provides abundant active sites to effectively capture LiPSs and accelerate the catalytic conversion process, originating from modulating the surface electronic structure of the metal Cu by introducing Ir atoms to affect the 3d-orbital distribution. All of the above are strongly supported by a range of characterization studies and density functional theory calculations. Benefiting from the above advantages, the LSBs generally show satisfactory cycling performance. Apart from exhibiting a terrific initial specific capacity of 1288 mA h g-1 at 0.2 C, they can also keep long-term cycling stability under a high current density up to 5 C together with a slow specific capacity decay ratio (0.033%) per cycle after 1000 cycles. In addition, it is worth mentioning that a high areal capacity (4.7 mA h cm-2) with a low E/S ratio (6.2 μL mg-1) could still be accomplished at higher sulfur loading (4.3 mg cm-2).

Rational design of ultrathin Mo2C/C nanosheets decorated on mesoporous hollow carbon spheres as a multifunctional sulfur host for advanced Li-S batteries

Developing sulfur hosts with reasonable structure and effective catalyst is essential for lithium-sulfur (Li-S) batteries. Herein, a novel multifunctional sulfur host composed of hollow carbon spheres with mesoporous channels (MHCS) coupled with few ultrathin Mo2C/C nanosheets embedded with Mo2C nanocrystals ([email protected]2C/C) has been prepared via one-pot self-assembly and in-situ grown strategies. The Mo2C/C nanosheets with heterostructure can shorten the electron/ion transport path, and ultra-small Mo2C nanocrystals with abundant active sites contribute to enhancing chemical adsorption towards polysulfides and propel their conversion. Meanwhile, the MHCS facilitates physical adsorption towards polysulfides, effective sulfur/electrolyte permeation, fast electron/ion transportation, and sufficient buffering for volume change. Given these, the multifunctional [email protected]2C/C-S cathode demonstrates an initial specific capacity of 1316.8 mAh g−1 at 0.1 C and outstanding cycling stability with an average capacity decay rate of 0.045 % for 500 cycles at 0.5 C. Moreover, [email protected]2C/C-S cathode with high areal sulfur loading of 4.5 mg cm−2 can deliver a high initial discharge specific capacity of 797.4 mAh g−1, and a reversible capacity of 542.7 mAh g−1 after 500 cycles at 0.5 C. It is expected this work could provide a new perspective to the rational design of sulfur hosts for Li-S batteries with enhanced performance.

A hollow Co0.12Ni1.88S2/NiO heterostructure that synergistically facilitates lithium polysulfide adsorption and conversion for lithium-sulfur batteries

• An ingenious Co 0.12 Ni 1.88 S 2 /NiO heterostructure with a hollow and semi-open architecture was engineered in situ , which synergistically enhanced lithium polysulfide adsorption and conversion for lithium-sulfur batteries. • The considerable electrochemical impedance variation was observed via in situ EIS measurements, which was proved to be related to the content of soluble LiPSs in the electrolyte. • The mechanisms of the strong affinities between Co 0.12 Ni 1.88 S 2 /NiO and lithium polysulfides, and the catalytic effect were further investigated by theoretical calculations. The significant capacity deterioration and inadequate cycling lifespan that are mainly caused by the undesirable “shuttle effect” and torpid redox kinetics have encumbered the development of practically applicable lithium-sulfur (Li-S) battery technology. Modifying sulfur cathodes with lithium polysulfide (LiPS) adsorptive and electrocatalytic host materials is a promising approach to resolving these issues. Herein, a Co 0.12 Ni 1.88 S 2 /NiO heterostructure, which has multiple merits, is designed and serves as a sulfur host to improve the electrochemical performance of Li-S batteries. Possessing strong LiPS adsorbability and excellent electrocatalytic activity, the heterostructural Co 0.12 Ni 1.88 S 2 /NiO exhibits favorable synergistic effects, which effectively facilitate the anchoring and converting of diffused LiPSs. As a result, the corresponding cell delivers rapid redox kinetics and higher sulfur utilization. An impressive initial discharge capacity of 1424.8 mAh g −1 and a reversible capacity near 1056.7 mAh g −1 at 1 C over 1000 cycles are achieved with an average Coulombic efficiency of 98.8%. Benefiting from the unique nanoarchitecture and superior catalytic efficiency, only a very small amount of Co 0.12 Ni 1.88 S 2 /NiO (∼7 wt% in the cathode) is used as the sulfur host. The rational design of Co 0.12 Ni 1.88 S 2 /NiO in this work will hopefully offer inspiration for exploring advanced heterostructure materials for Li-S batteries and other electrochemical devices. Heterostructural Co 0.12 Ni 1.88 S 2 /NiO was engineered as a sulfur host for lithium-sulfur batteries. The catalytic effect and strong LiPS adsorbability synergistically promoted redox kinetics and LiPS conversion, which significantly improved the sulfur utilization during the charging and discharging processes.

Metal Ion Cutting-Assisted Synthesis of Defect-Rich MoS2 Nanosheets for High-Rate and Ultrastable Li2S Catalytic Deposition.

Active metal ions often show a strong cutting effect on the chemical bonds during high-temperature thermal processes. Herein, a one-pot metal ion cutting-assisted method was adopted to design defect-rich MoS2-x nanosheet (NS)/ZnS nanoparticle (NP) heterojunction composites on carbon nanofiber skeletons (CNF@MoS2-x/ZnS) via a simple Ar-ambience annealing. Results show that Zn2+ ions capture S2- ions from MoS2 and form into ZnS NPs, and the MoS2 NSs lose S2- ions and become MoS2-x ones. As sulfur hosts for lithium-sulfur batteries (LSBs), the CNF@MoS2-x/ZnS-S cathodes deliver a high reversible capacity of 1233 mA h g-1 at 0.1 C and keep 944 mA h g-1 at 3 C. Moreover, the cathodes also show an extremely low decay rate of 0.012% for 900 cycles at 2 C. Series of analysis indicate that the MoS2-x NSs significantly improve the chemisorption and catalyze the kinetic process of redox reactions of lithium polysulfides, and the heterojunctions between MoS2-x NSs and ZnS NPs further accelerate the transport of electrons and the diffusion of Li+ ions. Besides, the CNF@MoS2-x/ZnS-S LSBs also show an ultralow self-discharge rate of 1.1% in voltage. This research would give some new insights for the design of defect-rich electrode materials for high-performance energy storage devices.

The Fig-Like hierarchical Double-Shelled hollow TiN particles as sulfur host for Lithium-Sulfur batteries

Lithium-sulfur battery(LSB)’s commercial manufacturing has been mainly retarded by the “shuttle effect” and low electrical conductivity of polysulfides (LiPSs). Designing a cathode with hollow and hierarchically porous structures was expected to solve the above problems. Herein, a kind of TiN particles with the hierarchical hollow double-shelled structures was synthesized and applied to cathodes of LSB. The Fig-like hollow TiO2 particles (FHTiO2s) were firstly synthesized by the hard-template method. Subsequently, the Fig-like hierarchical hollow double-shelled TiN particles (FHTiNs) were synthesized by the template-free sequential transformation and separation approach (STSA). It was verified that the heating temperature and time were key parameters. Special Fig-like double-shell hollow structures could greatly increase the loading of S, and the excellent initial capacity of FHTiNs cathodes was up to 1159 mAh/g. On the one hand, the Fig-like framework in internal cavity and double-shell structures could promote the ultrahigh specific surface area, and the adsorption to LiPSs was improved by increasing active sites; On the other hand, the shuttle effect of LiPSs was weakened by the fig-like framework and double-shell structures, which slowed down the massive dissolution of sulfur in the electrolyte. As a result, the pleasant rate performance of FHTiNs cathodes was up to 400 mAh/g at 5C. This novel structures and synthesis method provided a new strategy for the designing of LSB cathodes.

Bamboo-shaped Co@NCNTs as superior sulfur host for Li-S batteries

Functional and active carbon material is of great concern in facilitating the performance of lithium-sulfur (Li-S) battery. In this work, we develop a bamboo-like nitrogen-doped carbon nanotubes (Co@NCNTs-2) with low cobalt metal content, which acts as not only the host matrix for sulfur loading but also an efficient catalyst for the adsorption and conversion of lithium polysulfides (LiPSs). The characterization results show that the Co particles are mainly encapsulated inside the Co@NCNTs-2, and the N species are mainly distributed on the outer surface of Co@NCNTs-2. The Co particles are the growth sites of carbon nanotubes and are wrapped by carbon to form Co@NCNTs-2. It is confirmed that the uniform graphitized structure contributes to charge transfer, while the enriched N species assist the trap and catalytic conversion of the polysulfides, thus helping to restrain the shuttle effect. As a result, the resultant Co@NCNTs-2-S cathode presents high reversible capacity at different current densities and exhibits superior cycling stability for 300 cycles at 0.5 C.

Three-dimensional structural confinement design of conductive metal oxide for efficient sulfur host in Lithium-sulfur batteries

The design of sulfur hosts with good conductivity, stable hierarchical porosity, and highly active sites is essential for efficient lithium-sulfur (Li-S) batteries. In this study, a porous structured conductive Nb-doped and oxygen-deficient TiO2 (Nb-TiO2−x) is developed to serve as high-performance sulfur host. The introduction of oxygen vacancies and Nb-doping not only benefits the electrical conductivity of the oxide matrix, but also promotes the lithium polysulfide (LiPS) trapping and catalytic conversions. Moreover, the Nb-TiO2−x host matrix is designed into a three-dimensional ordered macroporous (3DOM) skeleton implemented with microporous N-doped carbon (NC) fillers. The 3DOM framework provides large and stable space for sulfur accommodation, whereas the hollow NC polyhedrons afford additional microsporosity and active sites for sulfur confinement. Benefited from these unique superiorities, the NC@Nb-TiO2−x-based sulfur cathode exhibits a capacity fading rate of 0.025 % per cycle in 1000 cycles, and a 8.06 mAh cm−2 areal capacity at a raised sulfur loading of 8.0 mg cm−2 in coin-cell configuration. Moreover, the corresponding pouch cells demonstrate decent workability at flexible scenario as well as stable cycling behavior under 3.5 mg cm−2 sulfur loading and electrolyte-to-sulfur (E/S) ratio of 9.5 μL mg−1. This work provides a feasible pathway towards efficient and durable Li-S batteries.

Ultralong cycle life enabled by in situ growth of CoMo1−xP/Mo heterostructure for lithium-sulfur batteries

Lithium-sulfur batteries (Li-S batteries) are considered as promising new-generation electrochemical energy storage devices due to their extremely high theoretical energy density (2600 Wh kg−1) and theoretical specific capacity (1675 mAh g−1). However, numerous problems such as poor conductivity and the shuttle effect during discharge–charge process limit the practical application of lithium-sulfur batteries. In this work, porous tubular CoMo1−xP/Mo constructed by in situ growth of metal Mo was designed as the sulfur host for lithium-sulfur batteries. The introduction of Mo modulated the electronic structure of CoMoP to improve the conductivity of cathode and facilitate the redox kinetics, as well as the CoMo1−xP/Mo heterostructure was beneficial to inhibit the shuttle effect through the interaction with lithium polysulfides, which improved cycling stability. As a result, CoMo1−xP/Mo/S cathode had a low-capacity decay rate of only 0.029% per cycle after 2000 cycles at 0.5 C. This work provided a new perspective for the further design of high-performance lithium-sulfur battery cathode materials.

Catalytic Mo2C decorated hollow mesoporous carbon spheres as sulfur host for lithium-sulfur batteries with high sulfur loading

Hybrid structures as sulfur host materials have been proven to be an effective way to improve the electrochemical property of lithium-sulfur (Li–S) batteries. However, how to construct hybrid nanomaterials with reasonable structure and composition remains a challenge. Herein, the Mo2C nanoparticles grown on the surface of hollow mesoporous carbon spheres (HMCS@Mo2C) are synthesized as an effective sulfur host for Li–S batteries with high sulfur loading. In this hybrid structure, the HMCS can guarantee high sulfur loading, high-speed electron/ion transport, and sufficient buffer for volume change, and the Mo2C nanoparticles as effective catalysts significantly accelerate the conversion of polysulfides. Consequently, the as-prepared HMCS@Mo2C–S cathode demonstrates superb cyclic stability with a capacity decay rate of 0.065% for 500 cycles at 1 ​C. Impressively, HMCS@Mo2C–S cathode with high areal sulfur loading of 5.4 ​mg ​cm−2 can deliver a high specific capacity of 451.2 mAh g−1 after 500 cycles at 0.5 ​C. In addition, the preparation of HMCS@Mo2C is simple, feasible, and low cost. It is hoped that this work will provide new insight into the rational design of sulfur host materials integrating reasonable structure with an effective catalyst for Li–S batteries with high sulfur loading.

Confined Co9S8 nanocrystals into N/S-Co-doped carbon nanofibers as a chainmail-like electrocatalyst for high-performance lithium-sulfur batteries with high sulfur loading

Accelerating phase transposition efficiency of lithium polysulfides (LiPSs) to L2S and hampering the solution of LiPSs are the keys to stabilizing lithium-sulfur (Li-S) batteries. Hence, the sulfiphilic ultrafine Co9S8 nanoparticles embedded lithiophilic N, S co-doping carbon nanofibers (Co9S8/NSCNF) are prepared via the dual-template method, which are then used as sulfur host in Li-S batteries. Particularly, the double active sites (Co9S8 and N, S) in Co9S8/NSCNF are prone to form “Co-S”, “Li-O” or “Li-N” bonds, and then simultaneously improving the chemisorption and interface transposition capability of LiPSs. In case of the S@ Co9S8/NSCNF composites with high sulfur loading of 89% are employed as cathode, the cell possesses optimized “sulfiphilicity” and “lithiophilicity”, which achieves remarkable sulfur electrochemistry, including outstanding reversibility of 816.8mAhg−1 over 500 cycles at 1.0C, excellent rate property of 742.2mAhg-1at 5.0C, and long-term cycling with a low attenuation of 0.011% per cycle over 1800 cycles at 3.0C. Impressively, a remarkable areal capacity of 11.51mAhcm−2 is retained under the sulfur loading of 15.3 mg cm−2 for 50 cycles. This research will deepen the understanding of the complex LiPSs interface transposition procedure and provide new ideas for the design of new host materials.

Molten salts approach of metal-organic framework-derived nitrogen-doped porous carbon as sulfur host for lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries have attracted significant attention as next-generation energy storage systems owing to their high theoretical specific capacity (1675 mAh g−1) and energy density (2567 Wh kg−1). However, the low electrical conductivity of S and the dissolution of polysulfides in organic electrolytes pose significant challenges for their industrial applications. Herein, we report a facile, scalable, and solvent-free synthetic method based on metal–organic-framework (MOF) for synthesizing N-doped carbon-based materials with hierarchical porous structures and large specific surface areas (2297 m2 g−1) as efficient cathode hosts for Li-S batteries. The cathode materials were synthesized via solvent-free mixing, followed by the direct carbonization of adenine and tetracarboxylic acid with zinc acetate using the molten salt method. Zinc salt was employed as a template for mesopores as well as binding sites for other organic materials. The irregular surface morphology and N-doping of the resulting porous carbons act as physical barriers to confine polysulfides within the carbon matrix. The S-loaded cathode was stable and exhibited a discharge capacity of 555 mAh g−1 over 290 cycles at a current density of 0.5C, corresponding to the capacity retention of 63%. The facile modified MOF synthetic strategy, assisted by molten salt processing, holds promise for the synthesis of noble cathode materials for high-performance Li-S batteries.