Polysulfide Shuttling Research Articles

Configuring single-layer MXene nanosheet onto natural wood fiber via C–Ti–C covalent bonds for high-stability Li-S batteries

Lithium-sulfur batteries (LSBs) are considered promising candidates for next-generation battery technologies owing to their outstanding theoretical energy density and cost-effectiveness. However, the low conductivity and polysulfide shuttling effect of S cathodes severely hamper the practical performance of LSBs. Herein, in situ-generated single layer MXene nanosheet/hierarchical porous carbonized wood fiber (MX/PCWF) composites are prepared via a nonhazardous eutectic activation strategy coupled with pyrolysis-induced gas diffusion. The unique architecture, wherein single layer MXene nanosheets are constructed on carbonized wood fiber walls, ensures rapid polysulfide conversion and continuous electron transfer for redox reactions. The C–Ti–C bonds formed between MXene and PCWF can considerably expedite the conversion of polysulfides, effectively suppressing the shuttle effect. An impressive capacity of 1301.1 mA h g−1 at 0.5 C accompanied by remarkable stability is attained with the MX/PCWF host, as evidenced by the capacity maintenance of 722.6 mA h g−1 after 500 cycles. Notably, the MX/PCWF/S cathode can still deliver a high capacity of 886.8 mA h g−1 at a high S loading of 5.6 mg cm−2. The construction of two-dimensional MXenes on natural wood fiber walls offers a competitive edge over S-based cathode materials and demonstrates a novel strategy for developing high-performance batteries.

Rechargeable Metal-Sulfur Batteries: Key Materials to Mechanisms.

Rechargeable metal-sulfur batteries are considered promising candidates for energy storage due to their high energy density along with high natural abundance and low cost of raw materials. However, they could not yet be practically implemented due to several key challenges: (i) poor conductivity of sulfur and the discharge product metal sulfide, causing sluggish redox kinetics, (ii) polysulfide shuttling, and (iii) parasitic side reactions between the electrolyte and the metal anode. To overcome these obstacles, numerous strategies have been explored, including modifications to the cathode, anode, electrolyte, and binder. In this review, the fundamental principles and challenges of metal-sulfur batteries are first discussed. Second, the latest research on metal-sulfur batteries is presented and discussed, covering their material design, synthesis methods, and electrochemical performances. Third, emerging advanced characterization techniques that reveal the working mechanisms of metal-sulfur batteries are highlighted. Finally, the possible future research directions for the practical applications of metal-sulfur batteries are discussed. This comprehensive review aims to provide experimental strategies and theoretical guidance for designing and understanding the intricacies of metal-sulfur batteries; thus, it can illuminate promising pathways for progressing high-energy-density metal-sulfur battery systems.

Attenuating the Polysulfide Shuttle Mechanism by Separator Coating.

Lithium-sulfur batteries have a high energy density but lack cycle stability to reach market maturity. This is mainly due to the polysulfide shuttle mechanism, i. e., the leaching of active material from the cathode into the electrolyte and subsequent side reactions. We demonstrate how to attenuate the polysulfide shuttle by magnetron sputtering molybdenum oxysulfide, manganese oxide, and chromium oxide onto microporous polypropylene separators. The morphology of the amorphous coatings was analyzed by SEM and XRD. Electrochemical cyclization quantified how these coatings improved Coulombic efficiency and cycle stability. These tests were conducted in half cells. We compare the different performances of the different coatings with the known chemical and adsorption properties of the respective coating materials.

DFT Simulations Investigating the Trapping of Sulfides by 1T-LixMoS2 and 1T-LixMoS2/Graphene Hybrid Cathodes in Li-S Batteries

The aim of this study is to investigate new materials that can be employed as cathode hosts in Li-S batteries, which would be able to overcome the effect of the shuttling of soluble polysulfides and maximize the battery capacity and energy density. Density functional theory (DFT) simulations are used to determine the adsorption energy of lithium sulfides in two types of cathode hosts: lithiated 1T-MoS2 (1T-LixMoS2) and hybrid 1T-LixMoS2/graphene. Initial simulations of lithiated 1T-MoS2 structures led to the selection of an optimized 1T-Li0.75MoS2 structure, which was utilized for the formation of an optimized 1T-Li0.75MoS2 bilayer and a hybrid 1T-Li0.75MoS2/graphene bilayer structure. It was found that all sulfides exhibited super-high adsorption energies in the interlayer inside the 1T-Li0.75MoS2 bilayer and very good adsorption energy values in the interlayer inside the hybrid 1T-Li0.75MoS2/graphene bilayer. The placement of sulfides outside each type of bilayer, over the 1T-Li0.75MoS2 surface, yielded good adsorption energies in the range of −2 to −3.8 eV, which are higher than those over a 1T-MoS2 substrate.

Achieving a smooth “adsorption-diffusion-conversion” of polysulfides enabled by MnO2-ZnS p-n heterojunction for Li-S battery

The commercial application of lithium-sulfur batteries is primarily impeded by the constant shuttling of soluble polysulfides and sluggish redox kinetics. Nowadays, the discovery of the heterojunction, which combines materials with diverse properties, offers a new perspective for overcoming these obstacles. Herein, a functional coating separator for the lithium-sulfur battery is designed using a MnO2-ZnS p-n heterojunction with a spontaneous built-in electric field (BIEF). The MnO2 nanowire provides suitable adsorption capacity for polysulfides, while the abundant reactive sites brought by ZnS ensure efficient conversion. Moreover, the BIEF significantly facilitates the migration of electrons and polysulfides at the MnO2-ZnS interface, enabling a smooth “adsorption-diffusion-conversion” reaction mechanism. By serving as both the adsorption module and catalytic sites, this BIEF allows batteries utilizing separators modified with MnO2-ZnS heterojunction to achieve an impressive initial capacity of 1511.1 mAh g−1 at 0.1C and maintain a capacity decay rate of merely 0.048% per cycle at 2.0C after 1000 cycles. Even when increasing sulfur loading to 9.4 mg cm−2 in lean electrolyte (5.4 μL mg−1), the battery still exhibits an ultrahigh areal capacity of 6.0 mAh cm−2 after 100 cycles.

A highly efficient absorptive and catalytic self-supporting Fe2O3/CC host for high performance Li-S batteries

The lithium-sulfur (Li-S) battery is a promising energy storage system because of its high energy density and low cost. However, the shuttling of lithium polysulfides (LiPSs) and low conductivity of the S cathode are barriers to its practical application. Fe2O3 nanorods were grown on a carbon cloth (Fe2O3/CC) by a solvothermal reaction and calcination to obtain a cathode for the battery. The mesoporous structure of the Fe2O3 and the CC conducting network facilitates lithium-ion and electron transport. Meanwhile, the nanorod arrangement results in the exposure of more Fe2O3 active sites, which improves the adsorption and rapid conversion of LiPSs. As a result, a Li–S cell using a Fe2O3/CC cathode has a high capacity of 1 250 mAh g−1 at 0.1 C with an excellent life of over 100 cycles with a capacity retention of 67%. It also has a 70% capacity retention after 1 000 cycles at 0.2 C. The excellent electrochemical performance of the Fe2O3/CC cathode indicates its potential applications in Li-S batteries.

Engineering Spin State in Spinel Co3O4 nanosheets by V‐Doping for Bidirectional Catalysis of Polysulfides in Lithium–Sulfur Batteries

AbstractThe slow bidirectional conversion and fast shuttling of lithium polysulfides (LiPSs) remain the main obstacles that inhibit the practical application of lithium sulfur batteries (LSBs). Here, by engineering the in‐spin state of spinel oxides, V doping‐induced hexagonal nanosheets (V‐Co3O4 NS) with intermediate spin state (IS, t2g5 eg1) can form stable bond order toward LiS* based on the ligand field theory and molecular orbital theory, thus effectively accelerating the sulfur conversion kinetics. Owing to these merits, the V‐Co3O4 NS modified separator base battery achieves a high areal capacity of 15.37 mAh cm−2 with sulfur loading of 15.4 mg cm−2, and it displays a low‐capacity attenuation of 0.015% each cycle at 3.0 C for 1900 cycles.

A Two-Dimensional Heterostructured Covalent Organic Framework/Graphene Composite for Stabilizing Lithium–Sulfur Batteries

The implementation of a functional separator represents a highly encouraging approach to mitigating polysulfide shuttling in lithium–sulfur (Li–S). In this study, a two-dimensional (2D) 1,3,5-triformylphloroglucinol (Tp)-p-phenylenediamine (Pa) covalent organic framework/reduced graphene oxide (rGO) functional layer was introduced to enhance the performance of the commercial separator in Li–S batteries. The resulting 2D TpPa@rGO modified separators exhibit significantly improved electronic and ionic conductivity when compared to the unmodified separator, effectively mitigating lithium polysulfide shuttling and enhancing sulfur cathode utilization. It is indicated that a heterostructured composite of a nitrogen-group-containing COF and an electronic conductive addictive is an effective modification to the separator. Consequently, the modified cell demonstrated a minimal degradation rate of only 0.12% per cycle over 350 cycles at 0.5 C.

Active sites-rich zeolitic imidazolate framework/MXene heterostructure modified separator with improved Li+ transport for high-performance Li-S batteries

The inevitable shuttling of lithium polysulfides (LiPSs) and poor redox kinetics restrict real-world applications of lithium-sulfur (Li-S) batteries, although they have been paid plentiful attention. Herein, a thin and multifunctional heterostructure (ZIF-L/MXene), consisting of leaf-like zeolitic imidazolate framework sheets (ZIF-L) and two-dimensional layered Ti3C2Tx MXene nanosheets, is developed for modification of polyolefin-based separators. A good combination of the merits of the ZIF-L and MXene can hinder the restacking of MXene nanosheets and achieve a large specific surface area, thus exposing plentiful active sites for adsorption and catalytic reaction of LiPSs. Taking these obviously synergistic effects, the ZIF-L/MXene heterostructure modified separators not only alleviate the shuttling of LiPSs but also promote their kinetics conversion. Furthermore, with an improved electrolyte affinity, the ZIF-L/MXene modified separators can accelerate the transport of Li+. Thus, the modified separator endows a Li-S cell with an admirable discharge capacity of 1371.7 mAh g-1 at 0.2 C and favorable cycling stability, with a slow capacity decay ratio of 0.075% per cycle during 500 cycles. Even under a sulfur loading of ~ 4.1 mg cm-2, the Li-S battery can achieve an excellent capacity of 990.6 mAh g-1 at 0.1 C and maintain an excellent cycling performance. The novel ZIF-L/MXene heterostructure modified separator in this work can provide an alternative strategy for designing thin and light separators for high-performance Li-S batteries, via the enhancement of redox kinetics and reduction of shuttling of the LiPSs.

Metal-Coordinated Covalent Organic Frameworks as Advanced Bifunctional Hosts for Both Sulfur Cathodes and Lithium Anodes in Lithium-Sulfur Batteries.

The shuttling of polysulfides on the cathode and the uncontrollable growth of lithium dendrites on the anode have restricted the practical application of lithium-sulfur (Li-S) batteries. In this study, a metal-coordinated 3D covalent organic framework (COF) with a homogeneous distribution of nickel-bis(dithiolene) and N-rich triazine centers (namely, NiS4-TAPT) was designed and synthesized, which can serve as bifunctional hosts for both sulfur cathodes and lithium anodes in Li-S batteries. The abundant Ni centers and N-sites in NiS4-TAPT can greatly enhance the adsorption and conversion of the polysulfides. Meanwhile, the presence of Ni-bis(dithiolene) centers enables uniform Li nucleation at the Li anode, thereby suppressing the growth of Li dendrites. This work demonstrated the effectiveness of integrating catalytic and adsorption sites to optimize the chemical interactions between host materials and redox-active intermediates, potentially facilitating the rational design of metal-coordinated COF materials for high-performance secondary batteries.

Insights into the aspect ratio effects of ordered mesoporous carbon on the electrochemical performance of sulfur cathode in lithium-sulfur batteries

Tailoring porous host materials, as an effective strategy for storing sulfur and restraining the shuttling of soluble polysulfides in electrolyte, is crucial in the design of high-performance lithium-sulfur (Li-S) batteries. However, for the widely studied conductive hosts such as mesoporous carbon, how the aspect ratio affects the confining ability to polysulfides, ion diffusion as well as the performances of Li-S batteries has been rarely studied. Herein, ordered mesoporous carbon (OMC) is chosen as a proof-of-concept prototype of sulfur host, and its aspect ratio is tuned from over ∼ 2 down to below ∼ 1.2 by using ordered mesoporous silica hard templates with variable length/width scales. The correlation between the aspect ratio of OMCs and the electrochemical performances of the corresponding sulfur-carbon cathodes are systematically studied with combined electrochemical measurements and microscopic characterizations. Moreover, the evolution of sulfur species in OMCs at different discharge states is scrutinized by small-angle X-ray scattering. This study gives insight into the aspect ratio effects of mesoporous host on battery performances of sulfur cathodes, providing guidelines for designing porous host materials for high-energy sulfur cathodes.

DFT insights into the adsorption mechanisms of lithium polysulfides on Ni2P (0001) surface for lithium–sulfur batteries

Reliable and sustainable energy storage systems are crucial for a renewable energy future. The ultrahigh theoretical specific capacity and energy density of lithium–sulfur batteries (LSBs) make them one of the most promising next-generation battery technologies. However, their large-scale applications are seriously limited by rapid capacity fading and poor Coulombic efficiency owing to the shuttling of lithium polysulfides (LiPSs). Herein, we investigate nickel phosphide (Ni2P) as an effective host material to realize high-performance LSBs based on first-principles density functional theory (DFT) calculations. Our calculated adsorption energies of the LiPSs species reveal that the Ni2P(0001) surface possesses moderate to high adsorption strength and the adsorption process is facilitated via charge transfer from the LiPSs to the interacting Ni2P(0001) surface atoms. Due to the strong interactions between Ni2P(0001) and LiPSs (Li2Sx, x = 1, 2, 4, 6 and 8), we observe elongation of the intramolecular Li–S bonds in LiPSs upon their adsorption. The stronger adsorption of Li2S coupled with its spontaneous dissociation suggests a faster charging process could occur on the on Ni2P(0001) surface. These results demonstrate that Ni2P can provide effective anchoring sites for the soluble LiPSs, potentially having implications for the design of electrodes for practical LSBs.

Interfacial "Double-Terminal Binding Sites" Catalysts Synergistically Boosting the Electrocatalytic Li2S Redox for Durable Lithium-Sulfur Batteries.

Catalytic conversion of polysulfides emerges as a promising approach to improve the kinetics and mitigate polysulfide shuttling in lithium-sulfur (Li-S) batteries, especially under conditions of high sulfur loading and lean electrolyte. Herein, we present a separator architecture that incorporates double-terminal binding (DTB) sites within a nitrogen-doped carbon framework, consisting of polar Co0.85Se and Co clusters (Co/Co0.85Se@NC), to enhance the durability of Li-S batteries. The uniformly dispersed clusters of polar Co0.85Se and Co offer abundant active sites for lithium polysulfides (LiPSs), enabling efficient LiPS conversion while also serving as anchors through a combination of chemical interactions. Density functional theory calculations, along with in situ Raman and X-ray diffraction characterizations, reveal that the DTB effect strengthens the binding energy to polysulfides and lowers the energy barriers of polysulfide redox reactions. Li-S batteries utilizing the Co/Co0.85Se@NC-modified separator demonstrate exceptional cycling stability (0.042% per cycle over 1000 cycles at 2 C) and rate capability (849 mAh g-1 at 3 C), as well as deliver an impressive areal capacity of 10.0 mAh cm-2 even in challenging conditions with a high sulfur loading (10.7 mg cm-2) and lean electrolyte environments (5.8 μL mg-1). The DTB site strategy offers valuable insights into the development of high-performance Li-S batteries.

Catalytic Effect of Ammonium Thiosulfate as a Bifunctional Electrolyte Additive for Regulating Redox Kinetics in Lithium-Sulfur Batteries by Altering the Reaction Pathway.

Sluggish sulfur redox kinetics and incessant shuttling of lithium polysulfides (LiPSs) greatly influence the electrochemical properties of lithium-sulfur (Li-S) batteries and their practical applications. For this reason, ammonium thiosulfate (AMTS) with effective redox regulation capability has been proposed as a functional electrolyte additive to promote the bidirectional conversion of sulfur species and inhibit the shuttle effect of soluble LiPSs. During discharging, the S2O32- in AMTS can trigger the rapid reduction of LiPSs from long chains to short chains by a spontaneous chemical reaction with sulfur species, thereby decreasing the accumulation of LiPSs in the electrolyte. During charging, the NH4+ in the AMTS enhances the dissociation/dissolution of Li2S2/Li2S by hydrogen-binding interactions, which alleviates the electrode surface passivation and facilitates the reversible oxidation of short-chain sulfides back to long chains. The enhanced bidirectional redox kinetics brought about by AMTS endows Li-S cells with high reversible capacity, excellent cycle stability, and rate capability even under lean electrolyte conditions. This work not only illustrates an effective redox regulation strategy by an electrolyte additive but also investigates its catalytic reaction mechanism and Li corrosion behavior. The crucial criteria for screening additives that enable bidirectional redox mediation analogous to AMTS are summarized, and its application perspectives/challenges are further discussed.

Conductive Polymer-Based Interlayers in Restraining the Polysulfide Shuttle of Lithium-Sulfur Batteries.

Lithium-sulfur batteries (LSBs) are considered a promising candidate for next-generation energy storage devices due to the advantages of high theoretical specific capacity, abundant resources and being environmentally friendly. However, the severe shuttle effect of polysulfides causes the low utilization of active substances and rapid capacity fading, thus seriously limiting their practical application. The introduction of conductive polymer-based interlayers between cathodes and separators is considered to be an effective method to solve this problem because they can largely confine, anchor and convert the soluble polysulfides. In this review, the recent progress of conductive polymer-based interlayers used in LSBs is summarized, including free-standing conductive polymer-based interlayers, conductive polymer-based interlayer modified separators and conductive polymer-based interlayer modified sulfur electrodes. Furthermore, some suggestions on rational design and preparation of conductive polymer-based interlayers are put forward to highlight the future development of LSBs.

Catalytic Solid‐State Sulfur Conversion Confined in Micropores toward Superhigh Coulombic Efficiency Lithium‐Sulfur Batteries

AbstractAchieving the solid–solid conversion of sulfur is a fundamental solution to eliminating the shuttling of soluble polysulfides and improving the cycling stability of lithium‐sulfur batteries. However, the sluggish solid reaction kinetics seriously challenge the battery performance. In this work, a micropore‐confined catalysis strategy to achieve the smooth solid–solid conversion of sulfur is proposed. It is realized by storing sulfur in a microporous carbon host with narrow pore size and uniformly distributed single‐atom Co catalytic sites. The microporous structure avoids the contact of electrolyte solvents with the inner sulfur, preventing the formation and dissolution of polysulfides and efficiently suppressing sulfur loss during cycling. The introduced single‐atom Co catalytic sites promote the charge transfer to accelerate the solid–solid conversion of sulfur. When coupled with a liquid carbonate electrolyte, the battery exhibits a remarkably high Coulombic efficiency (CE) of ≈99.88% and a minimal capacity decay rate of ≈0.016% per cycle for 1000 cycles at 0.5 C. Even when coupled with the solid‐state electrolyte, the battery still delivers a significantly high capacity of 1100 mAh g−1 and a remarkably high CE of ≈99.83% over 200 cycles. This work reveals a promising solution for developing practical stable Li─S batteries.

Enabling fast diffusion/conversion kinetics by thiourea-induced wrinkled N, S co-doped functional MXene for lithium-sulfur battery

The long lifespan of high-energy density lithium-sulfur batteries (LSBs) is still hindered by severe polysulfide (PS) shuttling and sluggish sulfur reduction/evolution kinetics process. Herein, we report a facile preparation of thiourea-induced wrinkled nitrogen and sulfur co-doped functionalized MXene (NSMX) to modify the separator to enhance the ion diffusion and conversion kinetics for high-energy LSBs. The combination of theoretical calculations and experimental conclusions demonstrates that the introduction of N, S heteroatoms induces the shift of the d-band center in transition metal Ti towards the Fermi level and results in the robust bonding effect between N/S atoms and Li atom in PS, hence exhibiting admirable adsorption capability to PS and fast catalytic PS reversible conversion rate, which quickly deplete soluble high-order PS and expedites the depletion of the Li2S6 in high potential. The 2D wrinkled polar surface with excellent conductivity assures fast electron transfer and ion migration. Profiting from the enhancement of S utilization and the reduction of unfavorable accumulated Li2S6, the LSBs equipped with NSMX modified separators exhibit a high specific capacity of 1249 mAh g−1 at 0.2 C. At a high rate of 5 C, the LSBs also delivered an impressive reversible capacity of 600 mAh g−1. Moreover, a high capacity and stable cycling can be achieved even under the condition of high S load and lean electrolyte consumption.

Niobium Boride/Graphene Directing High-Performance Lithium-Sulfur Batteries Derived from Favorable Surface Passivation.

Efficient catalysts are needed to accelerate the conversion and suppress the shuttling of polysulfides (LiPSs) to promote the further development of lithium-sulfur (Li-S) batteries. Intermetallic niobium boride (NbB2) has indefinite potential due to superior catalytic activity. Nonetheless, the lack of a rational understanding of catalysis creates a challenge for the design of catalysts. Herein, a NbB2/reduced graphene oxide-modified PP separator (NbB2/rGO/PP) is rationally designed. Essential, an in-depth insight into the catalysis mechanism of NbB2 toward LiPSs is established based on experiments and multiperspective measurement characterization, ab initio molecular dynamics (AIMD), and density functional theory (DFT). It has been uncovered that the actual catalyst that interacts with LiPSs in NbB2 is the passivated surface with an oxide layer (O2-NbB2), which occurs through B-O-Li and Nb-O-Li bonds, rather than the clean NbB2 surface. And the decomposition barrier of Li2S is greatly reduced by a substantial margin, dropping from 3.390 to 0.93 and 0.85 eV on the Nb-O and B-O surfaces, respectively, with fast Li+ diffusivity. Consequently, the cell with NbB2/rGO/PP as a functional separator achieves a high discharge capacity of 873 mAh g-1 at 1C after 100 cycles. Moreover, the benefits of NbB2/rGO/PP can be effectively maintained even at a high sulfur loading of 7.06 mg cm-2 without significant reduction and with a low electrolyte/sulfur ratio of 8 μL mg-1s. This study enhances our understanding of the catalytic mechanism of Li-S systems and presents a promising approach for developing electrocatalysts that are resilient to poisoning.

Fe2O3-decorated hollow CNT as efficient cathode coatings for high-performance lithium-sulfur batteries

The performance of lithium-sulfur batteries is hindered by the negative impact of polysulfide shuttling and slow sulfur redox kinetics. To achieve high-performance lithium-sulfur batteries, it is necessary to eliminate or reduce the dissolution and diffusion of polysulfides. Herein, this work reports the utilization of Fe2O3-decorated hollow carbon nano-tubes (Fe2O3@CNT) as efficient cathode coatings to trap polysulfides, which has led to accelerated reaction kinetics and improved catalytic activity for polysulfide conversion. These attributes enable Fe2O3@CNT cathode coating battery to deliver an initial discharge-specific capacity of 1273 mAh g−1 at 0.1 C and only experience a capacity decay of 0.067% per cycle over 800 cycles at 1 C. These findings demonstrate that Fe2O3@CNT is a promising cathode coating material with the potential to significantly improve the performance of lithium-sulfur batteries by reducing polysulfide shuttling and enhancing reaction kinetics.

Bi-functional material SnSSe/rGO with anionic vacancies serves as a polysulfide shuttling blocker and lithium dendrite inhibitor

The notorious polysulfide shutting and the irregular lithium dendrites are the leading causes for hindering lithium-sulfur batteries’ marketization. Herein, a bi-functional material consisting of an anionic vacancy-rich SnSSe layer stacked with graphene (SnSSe/rGO) composite is proposed, which possesses the characteristics of simultaneously immobilizing polysulfides and suppressing dendritic growth. The enhanced sulfiphilicity enables SnSSe/rGO as a separator modification layer (SnSSe/rGO@PP) to effectively adsorb polysulfides and catalyze their rapid conversion. The Li-S half-cell containing SnSSe/rGO@PP exhibits long cycling stability and outstanding rate capacity. Moreover, SnSSe/rGO can regulate lithium deposition behavior due to its strong lithiophilicity and interaction with lithiated products. The lithium anode employing SnSSe/rGO electrode (SnSSe/rGO@Cu-Li) demonstrates low nucleation overpotential and stable plating/stripping cycling. Consequently, the prepared Li-S full cells demonstrate a remarkable area capacity of about 8.0 mAh cm−2, even when subjected to lean electrolyte (9.0 µL mg−1) and low N/P ratio (about 1.3) with high sulfur loading (11.2 mg). This study reveals a fresh perspective for designing efficient bi-functional materials to solve both the shuttle effect and lithium dendrites in high-energy-density Li-S batteries.