Efficient Sulfur Host Research Articles

MgCo layered double hydroxide-based yolk shell polyhedrons as multifunctional sulfur mediator for lithium–sulfur batteries

The development of efficient sulfur host materials to address the shuttle effect issues of lithium polysulfides (LiPSs) is crucial in the lithium–sulfur (Li–S) batteries but still challenging. In the present study, a novel yolk shell structured MgCo-LDH/ZIF-67 composite is designed as Li–S battery cathode. In this composite, the shell layer is MgCo layered double hydroxide constructed by partially etching ZIF-67 nanoparticle by Mg2+, and the core is the unreacted ZIF-67 particle. The unique yolk shell structure not only provides abundant pores for sulfur accommodation, but also facilitates the electrolyte penetration and ion transport. The ZIF-67 core exhibits strong polar adsorption to LiPSs through the Lewis acid-base interactions, and the micropores/mesoporous can further trap LiPSs. Meanwhile, the MgCo-LDH shell exposes enough sulfur-philic sites for enhancing chemisorption and catalyzes LiPSs conversion. As a result, when MgCo-LDH/ZIF-67 is used as sulfur host in the cathode, the cell achieves a high discharge capacity of 1121 mAh g−1 at 0.2 C, and an areal capacity of 5.0 mAh cm−2 under high sulfur loading of 5.8 mg cm−2. The S/MgCo-LDH/ZIF-67 electrode holds a promising potential for the development of Li–S batteries.

Multisize CoS2 Particles Intercalated/Coated-Montmorillonite as Efficient Sulfur Host for High-Performance Lithium-Sulfur Batteries.

The chemisorption and catalysis of lithium polysulfides (LiPSs) are effective strategies to suppress the shuttle effect in lithium-sulfur (Li-S) batteries. Herein, multisize CoS2 particles intercalated/coated-montmorillonite (MMT) as an efficient sulfur host is synthesized. As expected, the obtained S/CoS2 @MMT cathode achieves an absorption-catalysis synergistic effect through the polar MMT aluminosilicate sheets and the well-dispersed nano-micron CoS2 particles. Furthermore, efficient interlamellar ion pathways and interconnected conductive network are constructed within the composite host due to the intercalation/coating of CoS2 in/on MMT. Therefore, the S/CoS2 @MMT cathode achieves an outstanding rate performance up to 5C (∼548 mAh g-1 ) and a high cycling stability with low capacity decay of 0.063 and 0.067 % per cycle for 500 cycles at 1C and 2C, respectively. With a higher sulfur loading of 4.0 mg cm-2 , the cathode still delivers satisfactory rate and cycling performance. It shows that the CoS2 @MMT host has great application prospects in Li-S batteries.

Potassium hydroxide activated carbon derived from albumen as an efficient sulfur host for room temperature sodium-sulfur batteries

The room temperature sodium–sulfur (RT/NaS) battery provides a potential energy storage technology with high theoretical capacity and low cost. However, the gap between its practical performance and theoretical expectation confines its comprehensive implementation. In this work, a simple annealing process successfully synthesized a hierarchical micro/mesoporous egg carbon with KOH activation (ECK) from albumen as sulfur hosting for RT/NaS batteries. KOH activation plays a vital role in enhancing conductivity, surface area, and porosity. Elemental sulfur was loaded to the ECK through simple heat evaporation to form an ECK@S composite. Even at the high rate of 1 C, the discharge capacity of the ECK@S electrode reached 473 mAh/g and maintained 202 mAh/g after 800 cycles, representing an outstanding performance. Therefore, preparing micro/mesoporous egg carbon by KOH activation creates a promising electrode material for RT/NaS batteries.

Construction of hierarchical yolk-shell structured Mn3O4@NC as efficient sulfur hosts for Li–S batteries

The high theoretical capacity and abundant reserves of sulfur makes Li–S batteries a promising candidate for future energy-storage devices. However, the low electrical conductivity of sulfur and severe polysulfides dissolution and migration hinder it practical application. To address the problems, we design a hierarchical yolk-shell structure with polar metal oxide Mn3O4 yolks and N-doped carbon shells as sulfur host. The N-doped carbon shell enhances the conductivity and provide physical confinement to polysulfides while the Mn3O4 yolks have strong chemical bonding effect with polysulfides. Besides, the sufficient void space in yolk-shell structure can ensure a high sulfur loading content (80%) as well as accommodate severe volume change of sulfur during lithiation. Benefiting from these merits, the yolk-shell Mn3O4@NC/S electrode exhibit a high capacity of 581 mAh g-1 at 1 C and enhanced cycling stability with a capacity retain of 84% over 300 cycles at 0.5 C, which is superior to yolk-shell Mn3O4@NC/S with more Mn3O4 residual and N-doped carbon shells/S without Mn3O4 inside.

Synergetic enhancing cycling stability of Li-S battery by hollow SrTiO3 microspheres wrapped by reduced graphene oxide

LiPSs shuttle effect and cycling decay are still considered the main bottlenecks towards the practical application of Li-S batteries as commercial batteries. In the paper, we designed hollow SrTiO3 microspheres wrapped by reduced graphene oxide (SrTiO3@rGO) as efficient sulfur host materials with the aim of suppressing LiPSs shuttle and improving cycling stability of Li-S batteries. The hollow SrTiO3 microspheres wrapped by rGO, with appropriate binding energy to LiPSs, provide balancing surface adsorption and diffusion of LiPSs on nonconductive SrTiO3 and then promote its conversion on the interface, thus inhibiting the shuttle effect and greatly minimizing the active material irreversible loss in charge/discharge process. Meanwhile, the conductive rGO tightly wrapped on the surface of SrTiO3 offers an interconnected conductive network to support the fast electron/ion transfer. Profit from these merits, the SrTiO3 @rGO as sulfur host manifested superior cycling stability with a meager capacity decay rate of 0.0398% per cycle after 500 cycles at 0.2 C and an ultralow decay rate of 0.024% per cycle after 600 cycles at 1 C. The superior cycling stability suggested the hollow SrTiO3 @rGO was a potential candidate for the cathode of high-performance Li-S battery.

MOF-Derived Bifunctional Co0.85Se Nanoparticles Embedded in N-Doped Carbon Nanosheet Arrays as Efficient Sulfur Hosts for Lithium-Sulfur Batteries.

Lithium-sulfur batteries possess the merits of low cost and high theoretical energy density but suffer from the shuttle effect of lithium polysulfides and slow redox kinetics of sulfur. Herein, novel Co0.85Se nanoparticles embedded in nitrogen-doped carbon nanosheet arrays (Co0.85Se/NC) were constructed on carbon cloth as the self-supported host for a sulfur cathode using a facile fabrication strategy. The interconnected porous carbon-based structure of the Co0.85Se/NC could facilitate the rapid electron and ion transfer kinetics. The embedded Co0.85Se nanoparticles can effectively capture and catalyze lithium polysulfides, thus accelerating the redox kinetics and stabilizing sulfur cathodes. Therefore, the Co0.85Se/NC-S cathode could maintain a stable cycle performance for 400 cycles at 1C and deliver a high discharge specific capacity of 1361, 1001, and 810 mAh g-1 at current densities of 0.1, 1, and 3C, respectively. This work provides an efficient design strategy for high-performance lithium-sulfur batteries with high energy densities.

Synergistic coupling between Fe7S8-MoS2 heterostructure and few layers MoS2-embeded N-/P-doping carbon nanocapsule enables superior Li-S battery performances

Rechargeable Li-S batteries have attracted considerable interests because of their high theoretical energy density and cost-effectiveness. Nevertheless, the dissolution, shuttling and sluggish conversion of soluble lithium polysulfide intermediates seriously aggregates the cycle life and rate performances of batteries. In this work, a Fe7S8-MoS2 heterostructure decorated on few layers MoS2-embeded N-/P-doping carbon nanocapsule is for the first time developed as high efficient sulfur host for Li-S batteries. This structure offers a practical way to confine and catalyze the soluble lithium polysulfide. In particular, combining advantages with both coupling components, the Fe7S8-MoS2 heterostructure greatly enhances the adsorption abilities towards lithium polysulfide and accelerates their conversion kinetics. Besides, the few layers MoS2-embeded N-/P-doping carbon nanocapsule framework provides sufficient space and abundant adsorption sites to physically and chemically confine soluble lithium polysulfide, effectively suppressing their dissolution and shuttle effect. The synergistic coupling between the Fe7S8-MoS2 heterojunction catalyst and the delicately designed carbon architecture enables excellent rate capability and cycle performances for Li-S batteries. This work highlights the comprehensive material design matrix of dissimilar bandgaps sulfur hosts for future Li-S battery technologies.

Catalytic Oxidation of K2S via Atomic Co and Pyridinic N Synergy in Potassium–Sulfur Batteries

Potassium-sulfur batteries hold practical promise for next-generation batteries because of their high theoretical gravimetric energy density and low cost. However, significant impediments are the sluggish K2S oxidation kinetics and a lack of atomic-level understanding of K2S oxidation. Here, for the first time, we report the catalytic oxidation of K2S on a sulfur host with Co single atoms immobilized on nitrogen-doped carbon. On the basis of combined spectroscopic characterizations, electrochemical evaluation, and theoretical computations, we show a synergistic effect of dynamic Co-S and N-K interactions to catalyze K2S oxidation. The resultant potassium-sulfur battery exhibited high capacities of 773 and 535 mAh g-1 under high current densities of 1 and 2 C, respectively. These findings provide atomic-scale insights for the rational design of highly efficient sulfur hosts.

Graphene oxide-wrapped cobalt-doped oxygen-deficient titanium dioxide hollow spheres clusters as efficient sulfur immobilizers for lithium-sulfur batteries

The design of efficient sulfur host material is of great importance to address the undesirable polysulfide shuttling effect in the lithium-sulfur battery. Herein, we designed and constructed a sulfur immobilizer with multi-level sulfur storage space, which consists of the cluster of Co@TiO2 hollow spheres tightly wrapped by graphene oxide (labeled as Co@TiO2/GO). This structure provided a multi-level sulfur storage space, that is, the sulfur was encapsulated in the cavity of the Co@TiO2 hollow spheres, between Co@TiO2 spheres and GO sheets and in the interlaminar pores of GO. This enabled the inner and outer surfaces of the Co@TiO2 hollow spheres to better participate in the conversion reaction of lithium polysulfides (LPS). Moreover, the incorporated Co nanoparticles and abundance of oxygen vacancies effectively captured LPS and boosted their redox reaction kinetics. Therefore, this multi-level sulfur storage space is very beneficial to the storage and blockade of polysulfides and the improvement of the energy storage performance of the lithium-sulfur battery. Due to these beneficial structural features, the initial discharge capacity of Co@TiO2/GO/S cathode reached 807 mAh g−1 at 1C with a slow decay rate of 0.053% per cycle for 500 cycles, and high rate performance with a capacity of 552 mAh g−1 at 5C.

In Situ Synthesis of Vacancy-Rich Titanium Sulfide Confined in a Hollow Carbon Nanocage as an Efficient Sulfur Host for Lithium–Sulfur Batteries

<i>In Situ</i> Synthesis of Vacancy-Rich Titanium Sulfide Confined in a Hollow Carbon Nanocage as an Efficient Sulfur Host for Lithium–Sulfur Batteries

Metal-Organic Frameworks-Derived Nitrogen-Doped Porous Carbon Nanocubes with Embedded Co Nanoparticles as Efficient Sulfur Immobilizers for Room Temperature Sodium-Sulfur Batteries.

Room temperature sodium-sulfur (RT Na-S) batteries are considered a promising candidate for energy-storage due to their high energy-density and low-cost. However, the shutting effect of polysulfides and sluggish kinetics of sulfur redox reactions still severely limit their practical implementation. Herein, a new type of 3D hierarchical porous carbonaceous nanocubes is reported as efficient sulfur hosts, composed of carbon nanotubes (CNT) and Co nanoparticles (NPs) uniformly embedded into a nitrogen-doped carbon matrix (NC). Because of the high specific surface area, large degree of graphitization, and the synergetic effects between Co NPs and N-doping, the as-designed CNTs/Co@NC electrodes not only significantly increase polysulfides immobilization, but also efficiently catalyze sulfur redox reactions, as confirmed by experimental results and DFT calculations. When tested in a RT Na-S battery, the S@CNTs/Co@NC-0.25 cathode demonstrates outstanding electrochemical performance, achieving high initial specific capacity of 1200.3mAhg-1 at 0.1C, remarkable rate capability up to 5.0C (474.2mAhg-1 ), and superior cyclic performance of 450.5mAhg-1 (292mAhg-1 ) after 400 cycles at 1.0C (5.0C). The integration of a 3D hierarchical porous architecture with well-dispersed Co NPs of an electro-catalyst provides valuable insights based on structure-adsorption-catalysis engineering for advanced RT Na-S batteries.

Cobalt-iron oxide nanotubes decorated with polyaniline as advanced cathode hosts for Li-S batteries

Lithium-sulfur (Li-S) batteries are generally considered as potential candidates for sustainable energy storage systems owing to low cost and high theoretical energy storage capability. However, the actual implementation of sulfur cathode in Li-S batteries is seriously hampered by the undesirable shuttle effect of lithium polysulfides (LiPS), inferior electroconductibility of S/Li2S and huge volume change during lithiation/delithiation process. Herein, the CoFe2O4 nanotubes decorated with polyaniline (PANI) are rationally designed and fabricated as efficient sulfur hosts to handle these challenges. Specifically, both CoFe2O4 and PANI components possess strong chemical affinity to the soluble intermediate LiPS. Meanwhile, from the perspective of structural superiority, the internal void space of nanotubes can effectively accommodate active sulfur particles and tolerate the large volume change upon cycling. Besides, the conductive polymer of PANI can greatly improve the cathode conductivity and facilitate the electron transfer for active materials. More importantly, the S/CoFe2O4@PANI electrode achieves excellent cycling performance with superior initial capacity of 864.1 mAh g−1 and good reversible capacity retention with 582.6 mAh g−1 even after 500 cycles at 2 C rate.

Layered-like structure of TiO2-Ti3C2 Mxene as an efficient sulfur host for room-temperature sodium-sulfur batteries

The ideal sulfur supporting material for room-temperature sodium-sulfur (RT-NaS) batteries would concurrently incorporate adsorption capabilities, and high-electrical conductivity, which are essential for improving cycling stability and crucial for enhancing cycling stability and implementation in large-scale applications. In this work, the layered-like structure of TiO2-Ti3C2 Mxene was prepared by a simple hydrothermal method. The prepared TiO2-Ti3C2 material possesses a better optimal structure, which showed the evenly dispersed TiO2 on the Ti3C2 (Ti3C2). The layered-like structure material combines the decrease of volume expansion and the high conductivity of Ti3C2. After being impregnated with sulfur, a significant specific capacity of 255.196 mA h/g was achieved after 1500 cycles at a 1 C-rate with a low-capacity decay. The layered-like structure of TiO2-Ti3C2 prepared by the hydrothermal method is an auspicious cathode material for RT-NaS batteries.

Carbon nanotubes modified by Co3O4 nanoparticles as efficient sulfur host for high-performance lithium–sulfur batteries

Carbon nanotubes modified by Co3O4 nanoparticles as efficient sulfur host for high-performance lithium–sulfur batteries

Bimetallic Metal‐Organic Framework with High‐Adsorption Capacity toward Lithium Polysulfides for Lithium–sulfur Batteries

The practical application of Li‐S batteries is largely impeded by the “shuttle effect” generated at the cathode which results in a short life cycle of the battery. To address this issue, this work discloses a bimetallic metal‐organic framework (MOF) as a sulfur host material based on Al‐MOF, commonly called (Al)MIL‐53. To obtain a high‐adsorption capacity to lithium polysulfides (Li2Sx, 4 ≤ x ≤ 8), we present an effective strategy to incorporate sulfiphilic metal ion (Cu2+) with high‐binding energy to Li2Sx into the framework. Through a one‐step hydrothermal method, Cu2+ is homogeneously dispersed in Al‐MOF, producing a bimetallic Al/Cu‐MOF as advanced cathode material. The macroscopic Li2S4 solution permeation test indicates that the Al/Cu‐MOF has better adsorption capacity to lithium polysulfides than monometallic Al‐MOF. The sulfur‐transfusing process is executed via a melt‐diffusion method to obtain the sulfur‐containing Al/Cu‐MOF (Al/Cu‐MOF‐S). The assembled Li‐S batteries with Al/Cu‐MOF‐S yield improved cyclic performance, much better than that of monometallic Al‐MOF as sulfur host. It is shown that chemical immobilization is an effective method for polysulfide adsorption than physical confinement and the bimetallic Al/Cu‐MOF, formed by incorporation of sulfiphilic Cu2+ into porous MOF, will provide a novel and powerful approach for efficient sulfur host materials.

TiO2@C@MoS2Spheresas Efficient Sulfur Host for Lithium–Sulfur Batteries

TiO2@C@MoS2Spheresas Efficient Sulfur Host for Lithium–Sulfur Batteries

Porous Mo2C nanofibers with high conductivity as an efficient sulfur host for highly-stable lithium-sulfur batteries

Lithium-sulfur batteries is promising for the next-generation advanced energy storage systems, which have attracted a great deal of attention in recent years. However, the majority of substrates with both high electronic conductivity and full coverage of adsorption-catalysis synergy are difficult to achieve. Here, porous Mo2C nanofibers are successfully synthesized via using carbon fiber as a hard template, which Mo2C nanofibers as substrates exhibit high electron conductivity and fully covered adsorption sites. The cathode delivers an initial discharge capacity of ≈1080 mA h g−1 (at 0.1 C), and shows highly exposed (121) plane of Mo2C for anchoring and catalyzing Li2S. The excellent electrochemical performance indicates that the design offers a sample and practical avenue to develop highly-stable lithium-sulfur batteries.

Prussian blue analogs derived Fe-Ni-P@nitrogen-doped carbon composites as sulfur host for high-performance lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries have drawn a lot of attention owing to the high theoretical capacity of 1675 mAh g−1, environmental friendliness and relative abundance of sulfur. Nevertheless, the severe dissolution and migration of lithium polysulfides (LiPSs) and poor conductivity of sulfur greatly hinder the practical application of Li-S batteries. In this work, Fe-Ni-P@nitrogen-doped carbon (named as Fe-Ni-P@NC) derived from Fe-Ni Prussian blue analog (Fe-Ni PBA) was used as highly efficient sulfur host for Li-S batteries. The Fe-Ni-P particles not only enhance the adsorption of LiPSs but also effectively promote the conversion of LiPSs. In addition, the CN– of PBAs can readily generate nitrogen-doped carbon during pyrolysis, which can improve the conductivity of composites. Due to these advantages, Li-S batteries using S@Fe-Ni-P@NC composites cathodes exhibited good electrochemical performance with outstanding rate capability and stable cycling over 500 cycles with a lower capacity fading rate of 0.08% per cycle at 1 C.

Synergistic regulation of polysulfides immobilization and conversion by MOF-derived CoP-HNC nanocages for high-performance lithium-sulfur batteries

Abstract Lithium-sulfur (Li-S) batteries have drawn intense attention in the realm of electrochemical energy storage owing to their high theoretical energy density, as well as the natural abundance of sulfur and low cost. However, the severe shutting of polysulfides and sluggish reaction kinetics hinder the practical application of Li-S batteries. To solve these problems, MOF (ZIF-67) derived in-situ N-doped carbon nanocage embedded with CoP (CoP-HNC) as an efficient sulfur host for advanced Li-S batteries is proposed here. With the abundant porosity and cavity, hollow polar heteroatom N-doped carbon architecture can effectively alleviate volume expansion, buffer electrolyte and trap polysulfides. More importantly, the embedded polar CoP nanoparticles acted as an effective electrocatalyst not only anchor polysulfide intermediates, but also promote the redox kinetics toward polysulfides conversion remarkably, which is clearly proved by experimental results and DFT calculations. Benefiting from above advantages, Li-S batteries assembled with CoP-HNC electrode achieve a significantly enhanced sulfur utilization (about 800 mAh g−1 at 5 C), improved cycling stability and ultralow capacity decay rate of 0.02% per cycle after 1000 cycles. Even at high sulfur loading of 3.0 mg cm−2, the S/CoP-HNC electrode still delivers a high initial capacity of 866 mAh g−1 at 0.5 C. This work has guiding synergistically combining desired design and electrocatalysis in sulfur cathode for Li-S batteries.

Novel Ni/Ni2P@C hollow heterostructure microsphere as efficient sulfur hosts for high-performance lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries present the potential viable rechargeable batteries in the field of energy-storage devices. However, the migration of lithium polysulfides (LiPSs) and slow electrochemical reaction kinetics are still the intractable problems on the development of Li-S batteries. Herein, novel Ni/Ni2P@C hollow heterostructure microsphere, as the functional sulfur host material, is prepared by a facile approach. The study found that the novel hollow microsphere composed of porous carbon layer alleviates the volume expansion effect and effectively improves the electron transport during cycling process. In addition, the Ni/Ni2P heterostructure wrapped in carbon layer not only improves the adsorption of LiPSs, but also catalyzes their conversion reactions. Therefore, Li-S batteries with the S/Ni/Ni2P@C electrode exhibit high discharge capacity of 1187.3 mAh g−1 at 0.2 C in the first cycle, notable rate capability of 716.9 mAh g−1 at 3 C and outstanding reversible capacity of 636.6 mAh g−1 over the 500 cycles at 1 C. Owing to these excellent electrochemical performances, the Ni/Ni2P@C hollow heterostructure microsphere has promising applications for Li-S batteries.