Sulfur Host For Lithium-sulfur Batteries Research Articles

Triple Effect of "Conductivity-Adsorption-Catalysis" Enables MXene@FeCoNiP to be Sulfur Hosts for Lithium-Sulfur Batteries.

The weak chemical immobilization ability and poor catalytic effect of MXene inhibit its application in lithium-sulfur (Li-S) batteries. Herein, a novel MXene@FeCoNiP composite is rationally developed and utilized as a sulfur host for Li-S batteries. In this well-designed MXene-based nanostructure, the introduction of FeCoNiP in the interlayer of MXene nanosheets can not only effectively inhibit the restacking of MXene nanosheets but also act as an accelerator for the adsorption and catalysis of polysulfides to restrain the shuttling effect and facilitate the transformation of polysulfides. The existence of two-dimensional MXene nanosheets provides more active sites and improves the conductivity, which is beneficial for accelerating the reaction kinetics. Thus, the as-prepared MXene@FeCoNiP composites achieve an outstanding performance for Li-S batteries. This work provides an opportunity to construct an ideal sulfur host with the triple effect of "conductivity-adsorption-catalysis".

Preparation and application of NiS2/NiSe2 heterostructure as a sulfur host in lithium-sulfur batteries

The introduction of heterostructure in the cathode material of Li-S battery is an effective method to improve the redox reaction kinetics and suppress the shuttle effect of polysulfide. A metal sulfide/metal selenide (NiS2/NiSe2) heterostructure with hollow tetrahedral structure is prepared as a sulfur host of lithium-sulfur batteries. The prepared NiS2/NiSe2 heterostructure exhibits efficient charge transfer at the heterojunction interface, thereby enhancing catalytic activity for redox reactions of polysulfides and facilitating their rapid conversion. Moreover, the unique hollow tetrahedral structure, along with abundant surface pores, enables high sulfur loading capacity, providing abundant electrochemical reaction sites to enhance sulfur utilization efficiency. The results demonstrate that the NiS2/NiSe2 heterostructure material exhibits a remarkable initial capacity of 1338.9 mAh/g at 0.2 C, along with exceptional cycling stability (maintaining a capacity of 517.6 mAh/g after 200 cycles at 0.2 C, with only a negligible decay rate of 0.3% per cycle, retaining a capacity of 462.6 mAh/g after 500 cycles at 1 C, with an insignificant decay rate of merely 0.12% per cycle). The facile preparation of this NiS2/NiSe2 heterostructure not only enables the realization of lithium-sulfur batteries with exceptional capacity, but also opens up broader avenues for exploring high-performance heterogeneous materials.

La-doped Porous Fe2O3 Nanorods as Advanced Anodes for Lithium/Sodium Ion Batteries and Sulfur Host for Li-Sulfur Batteries.

Transition metal oxides are investigated as electrochemically active anodes for several years due to the merits of high specific capacity, low cost, abundant resources and controllable synthesis. But the poor cycle performances have hindered their further wide application. Herein, porous La-doped FeOOH nanorods have been synthesized through a facile hydrothermal method, which could be transformed into porous La-doped Fe2O3 (Fe2O3-La) via a simple heating process. Compared with the undoped Fe2O3, the Fe2O3-La showed larger surface area, higher specific capacities and more stable cycle performances for lithium/sodium ion batteries. In addition, as an advanced sulfur host for lithium-sulfur batteries, the Fe2O3-La also displayed much more excellent cycle and rate performances than the undoped Fe2O3. The superior electrochemical performances of the Fe2O3-La may could be attributed to the doping of La, which could induce more porous morphology and offer more reactive sites. The positive effects of La-doping for electrochemical performances of porous Fe2O3 nanorods provide novel insights for further applications of rare earth metal doping.

Arginine modification of hybrid cobalt/nitrogen Ti3C2Tx MXene and its application as a sulfur host for lithium-sulfur batteries

The shuttling effect of lithium polysulfides (LiPSs) is one of the challenges facing the commercialization, which leads to a significant capacity degradation. This paper proposes a novel method to promote polysulfide transformation by employing arginine to regulate the layer spacing of cobalt-nitrogen doped Ti3C2Tx MXene (Co-N@Ti3C2Tx-Arg). The results revealed that arginine effectively extended the interlayer spacing and promoted the homogeneous dispersion of Co and N atoms, thus endowing the sulfur host with a high catalytic activity during the charging and discharging processes. The extended interlayer spacing increased the specific surface area and captured sufficient LiPSs for subsequent catalytic conversions, while the Co and N doping on the surface of Ti3C2Tx significantly promoted the rapid conversion of the LiPSs to Li2S. Therefore, the S cathode coated with Co-N@Ti3C2Tx-Arg exhibited an excellent cycling stability with a low-capacity fading rate of 0.083% over 200 cycles in addition to a high reversible capacity of 1,365.4 mAh g-1 at 0.1 C.

Hollow and Silver-Cored Carbon Nanospheres as Effective Sulfur Hosts for Lithium-Sulfur Batteries

Lithium sulfur (Li–S) batteries are considered to be one of the most promising “beyond lithium-ion” energy storage technologies and the development of alternative battery chemistries is required to alleviate our reliance on the burning of fossil fuels 1. The high theoretical specific capacity of sulfur (1672mAh g-1) leads to a theoretical specific energy of ~2510 Wh kg-1, which is significantly greater than the state-of-the-art lithium-ion batteries 2. Further to this, sulfur is environmentally benign, low cost, and Li–S batteries do not rely on cobalt, or manganese 3, which are expensive, toxic, and have known ethical implications associated with their extraction and refining 4.While Li–S batteries boast many theoretical advantages, their practical application has been plagued with an array of limitations, mainly attributed to the poor electrical conductivity of sulfur, the significant volumetric expansions (80%) that can occur during cycling, and the soluble polysulfide intermediates 5. To tackle this, current research efforts have focused on using porous carbon materials (PCMs) to prepare sulfur/carbon composite cathodes 6,7. PCMs offer improved electrical conductivity, a large specific surface area, and pore diameters that are less than 1nm—which may confine the soluble polysulfides within the cathode matrix 8.In this study, the synthesis of hollow and silver-cored carbon nanospheres (HCNS, Ag-CNS) is detailed and their use as a multifunctional sulfur host for Li–S batteries is assessed. Ag-CNS are synthesised via a hydrothermal procedure from a simple saccharide solution coupled with a silver precursor. These Ag-CNS are further processed to prepare HCNS by etching the internal silver nanoparticle with an acid solution. The hydrothermal procedure described in this study offers a simplification to traditional HCNS synthesis methods which typically require the removal of templates, such as silica nanospheres, through etching with hazardous chemicals such as hydrofluoric acid.In this work, the structural and physical properties of HCNS and Ag-CNS are characterised using transmission electron microscopy, scanning electron microscopy, nitrogen gas adsorption, X-ray diffraction, Raman spectroscopy, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. The electrochemical performance of these materials, when used as a sulfur host, is investigated through the preparation, and testing of half cells with lithium metal anodes. Electrochemical testes include cyclic voltammetry and galvanostatic cycling data at different C-rates.

Reduced graphene oxide wrapped ZnCo layered double hydroxides microsphere as efficient sulfur host in lithium-sulfur batteries

The practical application of lithium-sulfur (Li-S) batteries is impeded by the shuttling of the polysulfide and slow sulfur electrochemical reaction. In this study, a reduced graphene oxide (rGO) wrapped hollow ZnCo layered double hydroxides (ZnCo-LDH) microsphere is fabricated as sulfur host material. The rGO nanosheets offer efficient charge transportation pathways. Meanwhile, the porous rGO and hollow ZnCo-LDH provide sufficient space for sulfur storage and mitigates the volume variation during battery charging and discharging. In addition, ZnCo-LDH exhibits excellent chemical adsorption capacity for polysulfides, and promotes their electrochemical conversion reactions. Benefited from these advantages, the S/ZnCo-LDH@rGO cathode delivers a high rate performance of 796.5 mAh g−1 at 5.0 C, and excellent stability performance with a capacity decay of 0.036 % per cycle after 500 cycles at 1.0 C. This study shows that the porous microsphere design of rGO wrapped layered double hydroxides has excellent application prospects as efficient sulfur host for Li-S batteries.

A coral-like composite of CoP-modified polyaniline-derived carbon chain skeleton as an efficient sulfur host for lithium-sulfur batteries

Lithium-sulfur batteries (LSBs) have attracted wide attention in the field of rechargeable batteries due to their high theoretical energy density. However, the severe “shuttle effect” of lithium polysulfides (LiPSs) and the slow conversion kinetics are key factors restricting the commercial application of LSBs. To address these issues, we designed and prepared a coral-like composite of CoP-modified polyaniline-derived carbon chain skeleton (CoP/C) as the sulfur host for LSBs. The carbon chains can provide multidirectional channels for the transport of Li+ and electron; and the uniformly scattered CoP can adsorb the LiPSs through chemical adsorption and simultaneously promote their conversion, thus the “shuttle effect” can be effectively alleviated. Meanwhile, the effect of the amount of aniline monomer on the electrochemical performance of sulfur cathode were studied. After sulfur loading, the CoP/C-300/S (with aniline monomer addition of 300 μL) exhibits the best electrochemical performance. At 1 C, after 500 cycles, it still maintains a reversible specific capacity of 478 mA h g−1, with a decay rate of 0.074% per cycle, indicating its excellent cycling stability. This work provides a new approach for the application of CoP material in advanced LSBs.

Deciphering the Influence of Anionic Electrons of Surface-Functionalized Two-Dimensional Electrides in Lithium-Sulfur Batteries.

Using transition metal compounds as sulfur hosts is regarded as a promising approach to suppress the polysulfide shuttle and accelerate redox kinetics for lithium-sulfur (Li-S) batteries. Herein, we report that a new kind of compound, electrides (exotic ionic crystalline materials in which electrons serve as anions), is efficient sulfur hosts for Li-S batteries for the first time. Based on the first-principles calculations, we found that two-dimensional (2D) electrides M2C (M = Sc, Y) exhibit unprecedentedly strong binding strength toward sulfur species and surface functionalization is necessary to passivate their activity. The 2D electrides modified with the F-functional group exhibit the best performance in terms of the adsorption energy and sulfur reduction process. A comparative study with a nonelectride reveals that the anionic electrons (AEs) of electrides aid in anchoring the soluble polysulfides. These results open an avenue for the application of electrides in Li-S batteries.

Sub-nanometer cobalt clusters embedded carbon networks to promote the kinetics of polysulfide conversion

The sluggish oxidation-reduction kinetics of sulfur and the shuttle effect of polysulfides are the bottlenecks restricting the practical application of lithium-sulfur batteries. In this study, subnanometer cobalt clusters were embedded into the cross-linked network of carbon sheets framework as high-efficiency sulfur host materials to promote the kinetics of polysulfides conversion for lithium-sulfur batteries. In such composite structure, the carbon network provides a rapid electron transfer pathway for interfacial electrochemical reaction. Co and N atoms can chemisorb polysulfides by forming Co-S and Li-N bonds with polysulfides, and catalyze the conversion of polysulfides. Such structure exhibits excellent rate performance and cycle stability during the cycle of lithium-sulfur battery. The capacity decay rate per cycle is only 0.061% for 500 cycles at 1 C, and the capacity retention rate is 69.4%. The composite structure developed in this work is a promising and high-efficiency sulfur host for lithium-sulfur batteries.

Ce-Doped Three-Dimensional Ni/Fe LDH Composite as a Sulfur Host for Lithium-Sulfur Batteries.

Lithium-sulfur batteries (LSBs) have become the most promising choice in the new generation of energy storage/conversion equipment due to their high theoretical capacity of 1675 mAh g-1 and theoretical energy density of 2600 Wh kg-1. Nevertheless, the continuous shuttling of lithium polysulfides (LiPSs) restricts the commercial application of LSBs. The appearance of layered double hydroxides (LDH) plays a certain role in the anchoring of LiPSs, but its unsatisfactory electronic conductivity and poor active sites hinder its realization as a sulfur host for high-performance LSBs. In this paper, metal organic framework-derived and Ce ion-doped LDH (Ce-Ni/Fe LDH) with a hollow capsule configuration is designed rationally. The hollow structure of Ce-Ni/Fe LDH contains a sufficient amount of sulfur. Fe, Ni, and Ce metal ions effectively trap LiPSs; speed up the conversion of LiPSs; and firmly anchor LiPSs, thus effectively inhibiting the shuttle of LiPSs. The electrochemical testing results demonstrate that a lithium-sulfur battery with capsule-type S@Ce-Ni/Fe LDH delivers the initial discharge capacities of 1207 mAh g-1 at 0.1 C and 1056 mAh g-1 at 0.2 C, respectively. Even at 1 C, a lithium-sulfur battery with S@Ce-Ni/Fe LDH can also cycle 1000 times. This work provides new ideas to enhance the electrochemical properties of LSBs by constructing a hollow capsule configuration.

Graphene/Heterojunction Composite Prepared by Carbon Thermal Reduction as a Sulfur Host for Lithium-Sulfur Batteries.

An interlayer nanocomposite (CC@rGO) consisting of a graphene heterojunction with CoO and Co9S8 was prepared using a simple and low-cost hydrothermal calcination method, which was tested as a cathode sulfur carrier for lithium-sulfur batteries. The CC@rGO composite comprises a spherical heterostructure uniformly distributed between graphene sheet layers, preventing stacking the graphene sheet layer. After the introduction of cobalt heterojunction on a graphene substrate, the Co element content increases the reactive sites of the composite and improves its electrochemical properties to some extent. The composite exhibited good cycling performance with an initial discharge capacity of 847.51 mAh/g at 0.5 C and a capacity decay rate of 0.0448% after 500 cycles, which also kept 452.91 mAh/g at 1 C and in the rate test from 3 C back to 0.1 C maintained 993.27 mAh/g. This article provides insight into the design of cathode materials for lithium-sulfur batteries.

Bimetal-Organic Framework Nanoboxes Enable Accelerated Redox Kinetics and Polysulfide Trapping for Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries are considered as promising candidates for next-generation energy storage systems in view of the high theoretical energy density and low cost of sulfur resources. The suppression of polysulfide diffusion and promotion of redox kinetics are the main challenges for Li-S batteries. Herein, we design and prepare a novel type of ZnCo-based bimetallic metal-organic framework nanoboxes (ZnCo-MOF NBs) to serve as a multifunctional sulfur host for Li-S batteries. The hollow architecture of ZnCo-MOF NBs can ensure fast charge transfer, improved sulfur utilization, and effective confinement of lithium polysulfides (LiPSs). The atomically dispersed Co-O4 sites in ZnCo-MOF NBs can firmly capture LiPSs and electrocatalytically accelerate their conversion kinetics. Benefiting from the multiple structural advantages, the ZnCo-MOF/S cathode shows high reversible capacity, impressive rate performance, and superior cycling stability for 300 cycles.

CoSe2 nanoparticles-decorated carbon nanofibers as a hierarchical self-supported sulfur host for high-energy lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries have gained widespread attention owing to their high theoretical energy density and low cost. However, the commercial application of these batteries is hindered by the severe shuttle effect and slow redox reaction kinetics of polysulfides. In this study, a hierarchically porous membrane consisting of CoSe2 nanoparticle-decorated carbon nanofibers containing carbon nanotubes (CoSe2@CNF/CNT) is constructed as a self-supported sulfur host for Li-S batteries. The hierarchical conductive network of CNFs/CNTs with N-doped porous carbon facilitates electron/ion transport and provides sufficient space to mitigate the volume expansion of lithium polysulfides (LiPSs). Moreover, the modified CoSe2 nanoparticles serve as both chemical trappers and electrocatalysts, chemically anchoring LiPSs and accelerating the redox kinetics to inhibit the shuttle effect. As a result, an initial specific discharge capacity of 1098.8 mA h g−1 is achieved at 1 C. Importantly, the cathode exhibits superior cycling stability with a capacity decay rate as low as 0.06% over 500 cycles. This work offers a feasible approach to designing multi-functional sulfur hosts for high-energy-density Li-S batteries.

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.