Polysulfide Redox Kinetics Research Articles

Synergistic Interaction of Strongly Polar Zinc Selenide and Highly Conductive Carbon Nanoframeworks Accelerates Redox Kinetics of Polysulfides.

Lithium-sulfur batteries (LSBs) have become strong competitors in secondary battery systems because of their superior theoretical capacity and energy density. However, due to the serious shuttle effect of soluble long-chain lithium polysulfides (LiPSs) and the slow solid-solid reaction kinetics, LSBs face some specific challenges, such as a short cycle life and low rate performance. The introduction of selenide/carbon composites derived from zeolite imidazolate frameworks (ZIFs) into separator coatings is a direct and effective solution to the aforementioned problems. Here, a zinc selenide/carbon catalyst material (ZnSe@C) was constructed and employed to modify commercial polypropylene (PP) separators to accelerate the conversion of intermediates. The highly polar ZnSe effectively fixes the active material on the cathode side by transferring electrons between elements with LiPSs and improves the utilization rate of sulfur. Concurrently, the highly conductive carbon nanoskeleton generated following the pyrolysis of ZIF-8 ensures the rapid transfer of charges during the catalytic reaction. The prepared ZnSe@C has a large specific surface area (250.07 m2 g-1) and mesoporous ratio (78.03%), which not only enhances adsorption and catalysis but also promotes the penetration of the electrolyte and the transport of Li+. Based on this, ZnSe@C/PP separator cells exhibit a low average capacity decay rate of 0.051% per cycle after 500 cycles at 1 C.

Heterostructure Mo2C/α-MoO3/G catalyst based heterogeneous catalysis/deposition mechanism for high-performance Li-S battery

Lithium-sulfur batteries (LSBs) have been recognized as a promising energy device due to their outstanding theoretical energy density and abundant resources. However, the commercial application remains obstruction by the sluggish redox kinetics and serious shuttle effect of polysulfides. Herein, a heterostructural Mo2C/α-MoO3/graphene (Mo2C/α-MoO3/G) catalyst based on a heterogeneous catalysis/deposition mechanism is proposed to address these issues. The prepared Mo2C/α-MoO3/G catalyst is feature with high-activity facet, fast electron delocalization and build-in electric field, which drastically promotes the redox kinetics of polysulfides on the surface of crystal phase. Simultaneously, the heterostructural Mo2C/α-MoO3/G catalyst is capable of capturing polysulfides effectively and eliciting the heterogeneous deposition of Li2S on the surface of amorphous phase, of which guarantee the efficient catalytic characteristic during the charge/discharge processes. In addition, the shuttle effect is restricted with a lower shuttle factor (∼0.02). Therefore, the assembled LSBs based Mo2C/α-MoO3/G catalyst modifying separator exhibits an impressive specific capacity of 1311.4 mAh g−1 at 0.2 C and excellent rate capability of 580.3 mAh g−1 at 4 C. More importantly, it demonstrated satisfied cycling stability even at a high sulfur loading mass (4.2 mgS cm−2) and lean electrolyte conditions (9.3 μL gS-1). This work reveals a novel paradigm for optimizing the kinetics behaviors to achieve the commercialization of LSBs.

Ultrafine Mo2N Quantum Dots Embedded in N-Doped Graphene Sheets Enable Efficient Adsorption-Catalytic Transformation of Polysulfides.

Because of the high theoretical energy density of 2600 Wh kg-1, lithium-sulfur batteries (LSBs) are anticipated to be among the next generation of high-energy-density storage technologies. However, the practical application of LSBs has been severely hampered by the significant shuttle effect and slow redox kinetics of polysulfides (LiPSs). To address the above problems, in this paper, the concept of quantum dots (QDs) was introduced to design and synthesize Mo2N QD-modified N-doped graphene nanosheets (marked as Mo2N-QDs@NG), which were used as separator modification materials for LSBs. The experimental results demonstrated that the introduction of Mo2N QDs avoids stacking of graphene sheets and provides more active sites for the conversion of LiPSs. Moreover, Mo2N enhances the chemical fixation and catalyzes the liquid-solid conversion of soluble LiPSs by forming Mo-S and Li-N bonds with LiPSs. Additionally, establishing Mo-C bonds with Mo2N, N-doped graphene sheets can facilitate the transport of electrons and ions and physically prevent the diffusion of LiPSs, thus creating a highly conducting carbon structure to support electrochemical reactions. Benefiting from the synergistic effect of chemical immobilization and catalysis of Mo2N QDs with the physical confinement of NG, Mo2N-QDs@NG-PP batteries exhibit enhanced electrochemical performance.

Single-Step PECVD Synthesis of Graphene@Carbon Nanotubes Electrocatalyst.

Graphene (Gr) and carbon nanotubes (CNTs), the two intriguing carbon nanomaterials, have presented great potential in serving as high-performance electrocatalysts in lithium-sulfur (Li-S) chemistry. The concurrent management of both materials would achieve a promoted synergistic effect. Nevertheless, there still remains a lack of an effective material synthesis route. Herein, a single-step plasma-enhanced chemical vapor deposition (PECVD) strategy is devised to prepare Gr@CNTs heterostructures with strong bonded connections. In the PECVD system, the damaged sidewalls generated in CNT tubes can serve as appropriate nucleation sites for further Gr growth. The formation mechanisms are thoroughly explored in aspects of both experimental characterizations and theoretical calculations. To confirm the validity of this approach, thus-constructed Gr@CNTs architectures are employed as the sulfur host, enabling boosted redox kinetics of polysulfides. This project provides fundamental insight into the mechanism exploration for single-step PECVD growth of Gr@CNTs heterostructure, hence promoting the practical application prospect of carbon nanomaterials toward Li-S systems.

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.

Multifunctional TiN‐MXene‐Co@CNTs Networks as Sulfur/Lithium Host for High‐Areal‐Capacity Lithium‐Sulfur Batteries

AbstractThe inevitable shuttling and slow redox kinetics of lithium polysulfides (LiPSs) as well as the uncontrolled growth of Li dendrites have strongly limited the practical applications of lithium‐sulfur batteries (LSBs). To address these issues, we have innovatively constructed the carbon nanotubes (CNTs) encapsulated Co nanoparticles in situ grown on TiN‐MXene nanosheets, denoted as TiN‐MXene‐Co@CNTs, which could serve simultaneously as both sulfur/Li host to kill “three birds with one stone” to (1) efficiently capture soluble LiPSs and expedite their redox conversion, (2) accelerate nucleation/decomposition of solid Li2S, and (3) induce homogeneous Li deposition. Benefiting from the synergistic effects, the TiN‐MXene‐Co@CNTs/S cathode with a sulfur loading of 2.5 mg cm−2 could show a high reversible specific capacity of 1129.1 mAh g−1 after 100 cycles at 0.1 C, and ultralong cycle life over 1000 cycles at 1.0 C. More importantly, it even achieves a high areal capacity of 6.3 mAh cm−2 after 50 cycles under a sulfur loading as high as 8.9 mg cm−2 and a low E/S ratio of 5.0 μL mg−1. Besides, TiN‐MXene‐Co@CNTs as Li host could deliver a stable Li plating/striping behavior over 1000 h.

Multifunctional TiN-MXene-Co@CNTs Networks as Sulfur/Lithium Host for High-Areal-Capacity Lithium-Sulfur Batteries.

The inevitable shuttling and slow redox kinetics of lithium polysulfides (LiPSs) as well as the uncontrolled growth of Li dendrites have strongly limited the practical applications of lithium-sulfur batteries (LSBs). To address these issues, we have innovatively constructed the carbon nanotubes (CNTs) encapsulated Co nanoparticles in situ grown on TiN-MXene nanosheets, denoted as TiN-MXene-Co@CNTs, which could serve simultaneously as both sulfur/Li host to kill "three birds with one stone" to (1) efficiently capture soluble LiPSs and expedite their redox conversion, (2) accelerate nucleation/decomposition of solid Li2S, and (3) induce homogeneous Li deposition. Benefiting from the synergistic effects, the TiN-MXene-Co@CNTs/S cathode with a sulfur loading of 2.5 mg cm-2 could show a high reversible specific capacity of 1129.1 mAh g-1 after 100 cycles at 0.1 C, and ultralong cycle life over 1000 cycles at 1.0 C. More importantly, it even achieves a high areal capacity of 6.3 mAh cm-2 after 50 cycles under a sulfur loading as high as 8.9 mg cm-2 and a low E/S ratio of 5.0 μL mg-1. Besides, TiN-MXene-Co@CNTs as Li host could deliver a stable Li plating/striping behavior over 1000 h.

Hollow and Porous N‐Doped Carbon Framework as Lithium‐Sulfur Battery Interlayer for Accelerating Polysulfide Redox Kinetics

AbstractLithium‐sulfur batteries (LSBs) have become one of the most powerful candidates for next‐generation battery technologies due to their high theoretical energy density and low cost. However, the notorious shuttle effect of soluble lithium polysulfides (LiPSs) and sluggish conversion reaction kinetics cause low sulfur utilization and inferior cycle life. Rational catalyst design on hierarchical pore structures and composition optimization is highly desired to realize synergetic enrichment, accommodation, and catalytic redox capacity of sulfur species. In this consideration, the hollow and porous N‐doped carbon framework is prepared, in which Co nanoparticles (NPs) are evenly embedded (denoted as Co‐HMCF) to modulate electron cloud density of carbons. Electrochemical tests and density functional theory (DFT) calculations demonstrate that Co‐HMCF could simultaneously deliver superior catalytic activity in accelerating LiPSs conversion as well as Li2S nucleation/decomposition to improve overall sulfur redox kinetics. Consequently, the Co‐HMCF interlayer significantly improves the battery performance, including high discharge capacity output (1538 mAh g−1 at 0.2 C), stable long‐term cycle (0.047% capacity decay per cycle for 800 cycles at 1.0 C), and exceptional rate capacity (582 mAh g−1 at 5.0 C).

Two-Dimensional Transition Metal Phosphides As Cathode Additive in Robust Lithium-Sulfur Batteries.

The development of advanced cathode materials able to promote the sluggish redox kinetics of polysulfides is crucial to bringing lithium-sulfur batteries to the market. Herein, two electrode materials: namely, Zr2PS2 and Zr2PTe2, are identified through screening several hundred thousand compositions in the Inorganic Crystal Structure Database. First-principles calculations are performed on these two materials. These structures are similar to that of the classical MXenes. Concurrently, calculations show that Zr2PS2 and Zr2PTe2 possess high electrical conductivity, promote Li ion diffusion, and have excellent electrocatalytic activity for the Li-S reaction and particularly for the Li2S decomposition. Besides, the mechanisms behind the excellent predicted performance of Zr2PS2 and Zr2PTe2 are elucidated through electron localization function, charge density difference, and localized orbital locator. This work not only identifies two candidate sulfur cathode additives but may also serve as a reference for the identification of additional electrode materials in new generations of batteries, particularly in sulfur cathodes.

Accelerated Conversion of Polysulfides for Ultra Long-Cycleof Li-S Batteryat High-Rateover Cooperative Cathode Electrocatalystof Ni0.261Co0.739S2/N-Doped CNTs.

Despite the very high theoretical energy density, Li-S batteries still need to fundamentally overcome the sluggish redox kinetics of lithium polysulfides (LiPSs) and low sulfur utilization that limit the practical applications. Here, highly active and stable cathode, nitrogen-doped porous carbon nanotubes (NPCTs) decorated with NixCo1-xS2 nanocrystals are systematically synthesized as multi-functional electrocatalytic materials. The nitrogen-doped carbon matrix can contribute to the adsorption of LiPSs on heteroatom active sites with buffering space. Also, both experimental and computation-based theoretical analyses validate the electrocatalytic principles of co-operational facilitated redox reaction dominated by covalent-site-dependent mechanism; the favorable adsorption-interaction and electrocatalytic conversion of LiPSs take place subsequently by weakening sulfur-bond strength on the catalytic NiOh 2+-S-CoOh 2+ backbones via octahedral TM-S (TM = Ni, Co) covalency-relationship, demonstrating that fine tuning of CoOh 2+ sites by NiOh 2+ substitution effectively modulates the binding energies of LiPSs on the NixCo1-xS2@NPCTs surface. Noteworthy, the Ni0.261Co0.739S2@NPCTs catalyst shows great cyclic stability with a capacity of up to 511 mAh g-1 and only 0.055% decay per cycle at 5.0 C during 1000 cycles together with a high areal capacity of 2.20 mAh cm-2 under 4.61mg cm-2 sulfur loading even after 200 cycles at 0.2 C. This strategy highlights a new perspective for achieving high-energy-density Li-S batteries.

CoN//Co9S8 co-embedded in reduced graphene oxide as catalyst for catalytic conversion of polysulfides

Lithium-sulfur (Li–S) batteries with high theoretical specific capacity of 1675 mAh g−1 and energy density of 2600 Wh kg−1 are considered as a promising candidate for energy conversion and storage devices in future. However, some critical dilemmas such as low real energy density, high solubility of ether-based electrolytes and slow redox kinetics of long-chain polysulfides remain unsettled hindering their development. Here we design and propose a high-performance sulfur host material constructed by growing CoN/Co9S8 nanoparticles enclosed in reduced graphene oxide (RGO) and Co9S8 modified separator to enhance the electrochemical performance of Li–S batteries. The results of first principal calculations confirm that the calculated adsorption energies of Li2S8, Li2S6, Li2S4 and Li2S2 on the Co9S8 (111) surface are lower than that of the CoN (111) surface, indicating that the Co9S8 has stronger adsorbing effect with polysulfides. Furthermore, the catalytic effect in Li2S6 symmetric batteries and the nucleation of the Li2S tests display that the CoN/Co9S8@RGO has a fast conversion reaction kinetics and catalytic effect of polysulfides, thereby inhibiting the leakage of the polysulfides. Consequently, the S@CoN/Co9S8@RGO cathode with Co9S8 layer represents a high discharge capacity of 1367.7 mAh g−1 at 0.1C and a prolonged lifespan over 700 cycles at 1 C with an extremely low decay rate of 0.06 % per cycle and high cycling stability.

Synergistic Effect of In2O3/NC-Co3O4 Interface on Enhancing the Redox Conversion of Polysulfides for High-Performance Li-S Cathode Materials at Low Temperatures.

Lithium-sulfur (Li-S) batteries are considered as a promising energy storage technology due to their high energy density; however, the shuttling effect and sluggish redox kinetics of lithium polysulfides (LiPSs) severely deteriorate the electrochemical performance of Li-S batteries. Herein, we report a novel configuration wherein In2O3 and Co3O4 are incorporated into N-doped porous carbon as a sulfur host material (In2O3@NC-Co3O4) using metal-organic framework-based materials to synergistically tune the catalytic abilities of different metal oxides for different reaction stages of LiPSs, achieving a rapid redox conversion of LiPSs. In particular, the introduction of N-doped carbon improved the electron transport of the materials. The polar interface of In2O3 and Co3O4 anchors both long- and short-chain LiPSs and catalyzes long-chain and short-chain LiPSs, respectively, even at low temperatures. Consequently, the Li-S battery with In2O3@NC-Co3O4 cathode materials delivered an excellent discharge capacity of 1042.4 mAh g-1 at 1 C and a high capacity retention of 85.1% after 500 cycles. Impressively, the In2O3@NC-Co3O4 cathode displays superior performances at high current density and low temperature due to the enhanced redox kinetics, delivering 756 mAh g-1 at 2 C (room temperature) and 755 mAh g-1 at 0.1 C (-20 °C).

Universal, minute-scale synthesis of transition metal compound nanocatalysts via graphene-microwave system for enhancing sulfur kinetics in lithium-sulfur batteries

The application of Li-S batteries on large scale is held back by the sluggish sulfur kinetics and low synthesis efficiency of sulfur host. In addition, the preparation of catalysts that promote polysulfide redox kinetics is complex and time-consuming, reducing the cost of raw materials in Li-S. Here, a universal synthetic strategy for rapid fabrication of sulfur cathode and metal compounds nanocatalysts is reported based on microwave heating of graphene. Heat-sensitive materials can achieve rapid heating due to graphene reaching 500 ℃ within 4 s via microwave irradiation. The MoP-MoS2/rGO catalyst demonstrated in this work was synthesized within 60 s. When used for catalysts for Li-S batteries whose graphene/sulfur cathodes were also synthesized by microwave heating, enhanced catalytic effect for sulfur redox reaction was verified via experimental and DFT theoretical results. Benefiting from fast redox reaction (MoP), smooth Li+ diffusion pathways (MoS2), and large conductive network (rGO), the assembled Li-S battery with MoP-MoS2/rGO-Add@CS displays a remarkable initial specific capacity, stable lithium anode and good cycle stability (in pouch cells) using this two-pronged strategy. The work provides a practical strategy for advanced Li-S batteries toward a wide range of applications.

Steering bidirectional polysulfide conversion in virtue of interface microenvironment of Ni/porous carbon Mott-Schottky heterojunctions

Originating from the notorious shuttle effect and intrinsically sluggish redox kinetics of polysulfides (especially under the conditions of high sulfur loadings and low electrolytes), the low capacity and sulfur utilization efficiency, unsatisfactory rate performance, and unremarkable cycle performance severely hinder the practical commercialization of lithium-sulfur batteries (LSBs). Furnishing rapid electron transfer and mass diffusion in virtue of interface modulation and nanostructure design is an effective strategy to enhance the activity of catalysts. Herein, a Mott-Schottky heterojunction composed of porous carbon (PC)-supported nickel (Ni) nanoparticles was fabricated on a functionalized carbon nanotube sponge (Ni/PC/FCNTS) via adjusting the geometric structure such as the particle size, aggregation state and pore volume (based on the different solvothermal reaction temperature of the Ni-MOF precursor and the high-temperature pyrolysis process). Transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) demonstrated the charge redistribution and a self-generated built-in electric field accelerated electron transfer at the heterogeneous interface between Ni and PC. Meanwhile, the high pore volume of Ni/PC/FCNTS-170 provided a reaction space for rapid ion diffusion and sulfur redox process. Benefiting from the synergistic effect, the derived S@Ni/PC/FCNTS-170 cells manifested excellent rate performance with a capacity of 784.2 mAh g-1 at 2 C and a high areal capacity of 8.09 mAh cm-2 with a high sulfur loading of 17.6 mg cm-2 and low electrolyte/sulfur of 11.3 µL mg-1.

Chemomechanics Engineering Promotes the Catalytic Activity of Spinel Oxides for Sulfur Redox Reaction

AbstractCooperative catalysis is a promising approach to enhance the sluggish redox kinetics of lithium polysulfides (LiPSs) for practical lithium–sulfur (Li–S) batteries. However, the elusory synergistic effect among multiple active sites makes it challenging to accurately customize the electronic structure of catalysts. Herein, a strategy of precisely tailoring eg orbitals of spinel oxides through chemomechanics engineering is porposed to regulate LiPSs retention and catalysis. By manipulating the regulable cations in MnxCo3‐xO4, it is theoretically and experimentally revealed that the lattice strain induced by the Jahn–Teller active and high‐spin Mn3+ at octahedral (Oh) sites can increase the eg occupancy of low‐spin Co3+Oh, which effectively regulates the chemical affinity toward LiPSs and establishes an unblocked channel for intrinsic charge transfer. This leads to a volcano‐type correlation between the eg occupancy at Oh sites and sulfur redox activity. Benefitting from the cooperative catalysis of dual‐active sites, MnCo2O4 with an average eg occupancy of 0.45 affords the most appropriate adsorption strength and rapid redox kinetics toward LiPSs, leading to remarkable rate performance and capacity retention for the assembled Li–S batteries. This work demonstrates the promise of chemomechanics engineering for optimizing the eg occupancy to achieve efficient sulfur redox catalysts.

Balanced Mass Transfer and Active Sites Density in Hierarchical Porous Catalytic Metal-Organic Framework for Enhancing Redox Reaction in Lithium-Sulfur Batteries.

Developing highly efficient catalysts, characterized by controllable pore architecture and effective utilization of active sites, is paramount in addressing the shuttle effect and sluggish redox kinetics of lithium polysulfides (LiPSs) in lithium-sulfur batteries (LSBs), which, however, remains a formidable challenge. In this study, a hierarchical porous catalytic metal-organic framework (HPC-MOF) with both appropriate porosity and abundant exposed catalytic sites is achieved through time-controlled precise pore engineering. It is revealed that the evolution of the porous structure and catalytic site density is time-dependent during the etching processes. The moderately etched HPC-MOF-M attains heterogeneous pores at various scales, where large apertures ensure fast mass transfer and micropores inherit high-density catalytic sites, enhancing utilization and catalytic kinetics at internal catalytic sites. Capitalizing on these advantages, LSB incorporating the HPC-MOF-M interlayer demonstrates a 164.6% improvement in discharge capability and an 83.3% lower decay rate over long-term cycling at 1.0C. Even under high sulfur loading of 7.1 mg cm-2 and lean electrolyte conditions, the LSB exhibits stable cycling for over 100 cycles. This work highlights the significance of balancing the relationship between mass transfer and catalytic sites through precise chemical regulation of the porous structure in catalytic MOFs, which are anticipated to inspire the development of advanced catalysts for LSBs.

Synergistic electrochemical catalysis by high-entropy metal phosphide in lithium–sulfur batteries

The shuttle effect and sluggish redox kinetics of polysulfides have hindered the development of lithium–sulfur batteries (LSBs) as premier energy storage devices. To address these issues, a high-entropy metal phosphide (NiCoMnFeCrP) was synthesized using the sol–gel method. NiCoMnFeCrP, with its rich metal species, exhibits strong synergistic effects and provides numerous catalytic active sites for the conversion of polysulfides. These active sites, possessing significant polarity, can bond with polysulfides. In situ ultraviolet–visible were conducted to monitor the dynamic changes in species and concentrations of polysulfides, validating the ability of NiCoMnFeCrP to facilitate the conversion of polysulfides. The batteries with the NiCoMnFeCrP catalyst as functional separators exhibited minimal capacity decay rates of 0.04 % and 0.23 % after 100 cycles at 0 °C and 60 °C, respectively. This indicates that the NiCoMnFeCrP catalyst possesses good thermal stability. Meanwhile, its area capacity can reach 4.78 mAh cm−2 at a high sulfur load of 4.54 mg cm−2. In conclusion, NiCoMnFeCrP achieves the objective of mitigating the shuttle effect and accelerating the kinetics of the redox reaction, thereby facilitating the commercialization of LSBs.

Electronic State‐Modulated Ni4N/Zn3N2 Heterogeneous Nanosheet Arrays Toward Dendrite‐Free and Kinetic‐Enhanced Li‐S Full Batteries

AbstractThe applications of lithium (Li)–sulfur (S) batteries are simultaneously hampered by the unlimited dendritic Li growth and the sluggish redox kinetics of polysulfides (LiPSs). In this work, an electronic state‐modulated Ni4N/Zn3N2 heterogeneous nanosheet arrays is painstakingly fabricated on the surface of carbon cloth (CC@Ni4N/Zn3N2) as an efficient bi‐service host to promote uniform Li deposition and boost efficient LiPSs catalysis. It is found that the electronic structure of Ni4N/Zn3N2 heterostructure is modulated to realize a rational transition metal d‐band center, and its built‐in electric field (BIEF) within the heterointerfaces facilitates the interfacial charge transfer, resulting in low Li deposition/migration energy barrier and efficient LiPSs adsorption/catalytic conversion kinetics. As a result, the as‐prepared CC@Ni4N/Zn3N2‐Li anode can enable the Li||Li symmetrical cells to possess a long‐term lifespan over 500 h even at 10 mA cm−2/20 mAh cm−2, and the as‐assembled LiNi0.8Co0.1Mn0.1O2||CC@Ni4N/Zn3N2‐Li full cell also shows an excellent cycling performance (95.8% capacity retention after 100 cycles). When used for both S and Li loading, the as‐assembled CC@Ni4N/Zn3N2‐S||CC@Ni4N/Zn3N2‐Li full cell exhibits an outstanding cycling stability (744 mAh g−1 after 1000 cycles at 2C). This work highlights the great potential of heterostructures for fabricating ideal bi‐serve hosts for both Li and S electrodes.

Customizing MXene@CoSe2 for cathode host of lithium–sulfur batteries to promote the redox kinetics of lithium polysulfides

Customizing MXene@CoSe2 for cathode host of lithium–sulfur batteries to promote the redox kinetics of lithium polysulfides

Crystalline-amorphous heterostructure on the phosphatized P-CoS2/CNT for augmenting the catalytic conversion kinetics of Li-S batteries

Crystalline-amorphous heterostructure catalyst is employed to conquer the notorious shuttle effect and sluggish redox kinetics of lithium polysulfides (LiPSs) intermediates of lithium-sulfur (Li-S) batteries. Herein, crystalline-amorphous heterostructure on the phosphatized cobalt disulfide/carbon nanotube (designated as P-CoS2/CNT) are served as the functional interlayer for Li-S batteries. Crystalline-amorphous heterostructure of P-CoS2/CNT is composed of high crystalline CoS2 core and amorphous Co(PO3)2 (a-Co(PO3)2) shell along with abundant active Co-O-P bonds. The crystalline CoS2 core and grain boundary defects on the heterostructure can prop up the well-pleasing electron conductivity when a-Co(PO3)2 accelerates the catalytic conversion kinetics of the polysulfides through the comprehensive survey in terms of chemical anchoring capability, nucleation barrier for Li2S, In-situ Raman for monitoring the shuttle case of polysulfides, and the analysis of inactive sulfur species on Li anode. In consequence, the Li-S battery using the P-CoS2/CNT functional separator delivers an outstanding low-capacity decay of only 0.048 % per cycle for 1000 cycles at 2C, and the LiPSs's shuttle effect is efficaciously restrained. Even with a high sulfur loading of 3.6 mg cm−2, the cell still maintains an outstanding areal capacity of 1.75 mAh cm−2 after 200 cycles at 1C. This work develops a scalable crystalline-amorphous heterostructure strategy using the conventional heteroatom modulation in aspire of accurately guiding the high-efficiency electrocatalyst served for the Li-S electrochemistry.