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Established in 1962, lithium–sulfur (Li–S) batteries boast a longer history than commonly utilized lithium–ion batteries counterparts such as LiCoO2 (LCO) and LiFePO4 (LFP) series, yet they have been slow to achieve commercialization. This delay, significantly impacting loading capacity and cycle life, stems from the long‐criticized low conductivity of the cathode and its byproducts, alongside challenges related to the shuttle effect, and volume expansion. Strategies to improve the electrochemical performance of Li–S batteries involve improving the conductivity of the sulfur cathode, employing an adamantane framework as the sulfur host, and incorporating catalysts to promote the transformation of lithium polysulfides (LiPSs). 2D MXene and its derived materials can achieve almost all of the above functions due to their numerous active sites, external groups, and ease of synthesis and modification. This review comprehensively summarizes the functionalization advantages of MXene‐based materials in Li–S batteries, including high‐speed ionic conduction, structural diversity, shuttle effect inhibition, dendrite suppression, and catalytic activity from fundamental principles to practical applications. The classification of usage methods is also discussed. Finally, leveraging the research progress of MXene, the potential and prospects for its novel application in the Li–S field are proposed. [ABSTRACT FROM AUTHOR]

Integration of solar cell and secondary battery cannot only promote solar energy application but also improve the electrochemical performance of battery. Lithium–sulfur battery (LSB) is an ideal candidate for photoassisted batteries owing to its high theoretical capacity. Unfortunately, the researches related the combination of solar energy and LSB are relatively lacking. Herein, a freestanding photoelectrode is developed for photoassisted lithium–sulfur battery (PALSB) by constructing a heterogeneous structured Au@N‐TiO2 on carbon cloths (Au@N‐TiO2/CC), which combines multiple advantages. The Au@N‐TiO2/CC photoelectrode can produce the photoelectrons to facilitate sulfur reduction during discharge process, while generating holes to accelerate sulfur evolution during charge process, improving the kinetics of electrochemical reactions. Meanwhile, Au@N–TiO2/CC can work as an electrocatalyst to promote the conversion of intermediate polysulfides during charge/discharge process, mitigating induced side reactions. Benefiting from the synergistic effect of electrocatalysis and photocatalysis, PALSB assembled with an Au@N‐TiO2/CC photoelectrode obtains ultrahigh specific capacity, excellent rate performance, and outstanding cycling performance. What is more, the Au@N‐TiO2/CC assembled PALSB can be directly charged under light illumination. This work not only expands the application of solar energy but also provides a new insight to develop advanced LSBs. [ABSTRACT FROM AUTHOR]

The development of lithium–sulfur (Li─S) batteries has been hampered by the shuttling effect of lithium polysulfides (LiPSs). An effective method to address this issue is to use an electrocatalyst to accelerate the catalytic conversion of LiPSs. In this study, heterogeneous MnP‐MnO2 nanoparticles are uniformly synthesized and embedded in porous carbon (MnP‐MnO2/C) as core catalysts to improve the reaction kinetics of LiPSs. In situ characterization and density functional theory (DFT) calculations confirm that the MnP‐MnO2 heterostructure undergo surface sulfidation during the charge/discharge process, forming the MnS2 phase. Surface sulfidation of the MnP‐MnO2 heterostructure catalyst significantly accelerated the SRR and Li2S activation, effectively inhibiting the LiPSs shuttling effect. Consequently, the MnP‐MnO2/C@S cathode achieves outstanding rate performance (10 C, 500 mAh g−1) and ultrahigh cycling stability (0.017% decay rate per cycle for 2000 cycles at 5 C). A pouch cell with MnP‐MnO2/C@S cathode delivers a high energy density of 429 Wh kg−1. This study may provide a new approach to investigating the surface sulfidation of electrocatalysts, which is valuable for advancing high‐energy‐density Li−S batteries. [ABSTRACT FROM AUTHOR]

Catalysis is crucial to improve redox kinetics in lithium–sulfur (Li–S) batteries. However, conventional catalysts that consist of a single metal element are incapable of accelerating stepwise sulfur redox reactions which involve 16‐electron transfer and multiple Li2Sn (n = 2–8) intermediate species. To enable fast kinetics of Li–S batteries, it is proposed to use high‐entropy alloy (HEA) nanocatalysts, which are demonstrated effective to adsorb lithium polysulfides and accelerate their redox kinetics. The incorporation of multiple elements (Co, Ni, Fe, Pd, and V) within HEAs greatly enhances the catalytically active sites, which not only improves the rate capability, but also elevates the cycling stability of the assembled batteries. Consequently, HEA‐catalyzed Li–S batteries achieve a high capacity up to 1364 mAh g−1 at 0.1 C and experience only a slight capacity fading rate of 0.054% per cycle over 1000 cycles at 2 C, while the assembled pouch cell achieves a high specific capacity of 1192 mAh g−1. The superior performance of Li–S batteries demonstrates the effectiveness of the HEA catalysts with maximized synergistic effect for accelerating S conversion reactions, which opens a way to catalytically improving stepwise electrochemical conversion reactions. [ABSTRACT FROM AUTHOR]

Abstract Integration of solar cell and secondary battery cannot only promote solar energy application but also improve the electrochemical performance of battery. Lithium–sulfur battery (LSB) is an ideal candidate for photoassisted batteries owing to its high theoretical capacity. Unfortunately, the researches related the combination of solar energy and LSB are relatively lacking. Herein, a freestanding photoelectrode is developed for photoassisted lithium–sulfur battery (PALSB) by constructing a heterogeneous structured Au@N‐TiO2 on carbon cloths (Au@N‐TiO2/CC), which combines multiple advantages. The Au@N‐TiO2/CC photoelectrode can produce the photoelectrons to facilitate sulfur reduction during discharge process, while generating holes to accelerate sulfur evolution during charge process, improving the kinetics of electrochemical reactions. Meanwhile, Au@N–TiO2/CC can work as an electrocatalyst to promote the conversion of intermediate polysulfides during charge/discharge process, mitigating induced side reactions. Benefiting from the synergistic effect of electrocatalysis and photocatalysis, PALSB assembled with an Au@N‐TiO2/CC photoelectrode obtains ultrahigh specific capacity, excellent rate performance, and outstanding cycling performance. What is more, the Au@N‐TiO2/CC assembled PALSB can be directly charged under light illumination. This work not only expands the application of solar energy but also provides a new insight to develop advanced LSBs.

Abstract Established in 1962, lithium–sulfur (Li–S) batteries boast a longer history than commonly utilized lithium–ion batteries counterparts such as LiCoO2 (LCO) and LiFePO4 (LFP) series, yet they have been slow to achieve commercialization. This delay, significantly impacting loading capacity and cycle life, stems from the long‐criticized low conductivity of the cathode and its byproducts, alongside challenges related to the shuttle effect, and volume expansion. Strategies to improve the electrochemical performance of Li–S batteries involve improving the conductivity of the sulfur cathode, employing an adamantane framework as the sulfur host, and incorporating catalysts to promote the transformation of lithium polysulfides (LiPSs). 2D MXene and its derived materials can achieve almost all of the above functions due to their numerous active sites, external groups, and ease of synthesis and modification. This review comprehensively summarizes the functionalization advantages of MXene‐based materials in Li–S batteries, including high‐speed ionic conduction, structural diversity, shuttle effect inhibition, dendrite suppression, and catalytic activity from fundamental principles to practical applications. The classification of usage methods is also discussed. Finally, leveraging the research progress of MXene, the potential and prospects for its novel application in the Li–S field are proposed.

Abstract The development of lithium–sulfur (Li─S) batteries has been hampered by the shuttling effect of lithium polysulfides (LiPSs). An effective method to address this issue is to use an electrocatalyst to accelerate the catalytic conversion of LiPSs. In this study, heterogeneous MnP‐MnO2 nanoparticles are uniformly synthesized and embedded in porous carbon (MnP‐MnO2/C) as core catalysts to improve the reaction kinetics of LiPSs. In situ characterization and density functional theory (DFT) calculations confirm that the MnP‐MnO2 heterostructure undergo surface sulfidation during the charge/discharge process, forming the MnS2 phase. Surface sulfidation of the MnP‐MnO2 heterostructure catalyst significantly accelerated the SRR and Li2S activation, effectively inhibiting the LiPSs shuttling effect. Consequently, the MnP‐MnO2/C@S cathode achieves outstanding rate performance (10 C, 500 mAh g−1) and ultrahigh cycling stability (0.017% decay rate per cycle for 2000 cycles at 5 C). A pouch cell with MnP‐MnO2/C@S cathode delivers a high energy density of 429 Wh kg−1. This study may provide a new approach to investigating the surface sulfidation of electrocatalysts, which is valuable for advancing high‐energy‐density Li−S batteries.

Abstract Catalysis is crucial to improve redox kinetics in lithium–sulfur (Li–S) batteries. However, conventional catalysts that consist of a single metal element are incapable of accelerating stepwise sulfur redox reactions which involve 16‐electron transfer and multiple Li2Sn (n = 2–8) intermediate species. To enable fast kinetics of Li–S batteries, it is proposed to use high‐entropy alloy (HEA) nanocatalysts, which are demonstrated effective to adsorb lithium polysulfides and accelerate their redox kinetics. The incorporation of multiple elements (Co, Ni, Fe, Pd, and V) within HEAs greatly enhances the catalytically active sites, which not only improves the rate capability, but also elevates the cycling stability of the assembled batteries. Consequently, HEA‐catalyzed Li–S batteries achieve a high capacity up to 1364 mAh g−1 at 0.1 C and experience only a slight capacity fading rate of 0.054% per cycle over 1000 cycles at 2 C, while the assembled pouch cell achieves a high specific capacity of 1192 mAh g−1. The superior performance of Li–S batteries demonstrates the effectiveness of the HEA catalysts with maximized synergistic effect for accelerating S conversion reactions, which opens a way to catalytically improving stepwise electrochemical conversion reactions.

The sluggish kinetics of sulfur conversions have long been hindering the implementation of fast and efficient sulfur electrochemistry in lithium–sulfur (Li–S) batteries. In this regard, herein the unique chromium boride (CrB) is developed via a well‐confined mild‐temperature thermal reaction to serve as an advanced sulfur electrocatalyst. Its interstitial‐alloy nature features excellent conductivity, while the nano‐lamination architecture affords abundant active sites for host‐guest interactions. More importantly, the CrB nanocatalyst demonstrates a dual sulphophilicity with simultaneous Cr─S and B─S bondage for establishing strong interactions with the intermediate polysulfides. As a result, significant stabilization and promotion of sulfur redox behavior can be achieved, enabling an excellent Li–S cell cyclability with a minimum capacity fading rate of 0.0176% per cycle over 2000 cycles and a favorable rate capability up to 7 C. Additionally, a high areal capacity of 5.2 mAh cm−2, and decent cycling and rate performances are still attainable under high sulfur loading and low electrolyte dosage. This work offers a facile approach and instructive insights into metal boride sulfur electrocatalyst, holding a good promise for pursuing high‐efficiency sulfur electrochemistry and high‐performance Li–S batteries. [ABSTRACT FROM AUTHOR]

The catalytic performance of metal–organic frameworks (MOFs) in Li‐S batteries is significantly hindered by unsuitable pore size, low conductivity, and large steric contact hindrance between the catalytic site and lithium polysulfide (LPSs). Herein, the smallest π‐conjugated hexaaminobenzene (HAB) as linker and Ni(II) ions as skeletal node are in situ assembled into high crystallinity Ni‐HAB 2D conductive MOFs with dense Ni‐N4 units via dsp2 hybridization on the surface of carbon nanotube (CNT), fabricating Ni‐HAB@CNT as separator modified layer in Li‐S batteries. As‐obtained unique π‐d conjugated Ni‐HAB nanostructure features ordered micropores with suitable pore size (≈8 Å) induced by HAB ligands, which can cooperate with dense Ni‐N4 chemisorption sites to effectively suppress the shuttle effect. Meanwhile, the conversion kinetics of LPSs is significantly accelerated owing to the small steric contact hindrance and increased delocalized electron density endued by the planar tetracoordinate structure. Consequently, the Li‐S battery with Ni‐HAB@CNT modified separator achieves an areal capacity of 6.29 mAh cm−2 at high sulfur loading of 6.5 mg cm−2 under electrolyte/sulfur ratio of 5 µL mg−1. Moreover, Li‐S single‐electrode pouch cells with modified separators deliver a high reversible capacity of 791 mAh g−1 after 50 cycles at 0.1 C with electrolyte/sulfur ratio of 6 µL mg−1. [ABSTRACT FROM AUTHOR]

Abstract The sluggish kinetics of sulfur conversions have long been hindering the implementation of fast and efficient sulfur electrochemistry in lithium–sulfur (Li–S) batteries. In this regard, herein the unique chromium boride (CrB) is developed via a well‐confined mild‐temperature thermal reaction to serve as an advanced sulfur electrocatalyst. Its interstitial‐alloy nature features excellent conductivity, while the nano‐lamination architecture affords abundant active sites for host‐guest interactions. More importantly, the CrB nanocatalyst demonstrates a dual sulphophilicity with simultaneous Cr─S and B─S bondage for establishing strong interactions with the intermediate polysulfides. As a result, significant stabilization and promotion of sulfur redox behavior can be achieved, enabling an excellent Li–S cell cyclability with a minimum capacity fading rate of 0.0176% per cycle over 2000 cycles and a favorable rate capability up to 7 C. Additionally, a high areal capacity of 5.2 mAh cm−2, and decent cycling and rate performances are still attainable under high sulfur loading and low electrolyte dosage. This work offers a facile approach and instructive insights into metal boride sulfur electrocatalyst, holding a good promise for pursuing high‐efficiency sulfur electrochemistry and high‐performance Li–S batteries.

Abstract The catalytic performance of metal–organic frameworks (MOFs) in Li‐S batteries is significantly hindered by unsuitable pore size, low conductivity, and large steric contact hindrance between the catalytic site and lithium polysulfide (LPSs). Herein, the smallest π‐conjugated hexaaminobenzene (HAB) as linker and Ni(II) ions as skeletal node are in situ assembled into high crystallinity Ni‐HAB 2D conductive MOFs with dense Ni‐N4 units via dsp2 hybridization on the surface of carbon nanotube (CNT), fabricating Ni‐HAB@CNT as separator modified layer in Li‐S batteries. As‐obtained unique π‐d conjugated Ni‐HAB nanostructure features ordered micropores with suitable pore size (≈8 Å) induced by HAB ligands, which can cooperate with dense Ni‐N4 chemisorption sites to effectively suppress the shuttle effect. Meanwhile, the conversion kinetics of LPSs is significantly accelerated owing to the small steric contact hindrance and increased delocalized electron density endued by the planar tetracoordinate structure. Consequently, the Li‐S battery with Ni‐HAB@CNT modified separator achieves an areal capacity of 6.29 mAh cm−2 at high sulfur loading of 6.5 mg cm−2 under electrolyte/sulfur ratio of 5 µL mg−1. Moreover, Li‐S single‐electrode pouch cells with modified separators deliver a high reversible capacity of 791 mAh g−1 after 50 cycles at 0.1 C with electrolyte/sulfur ratio of 6 µL mg−1.

Lithium–sulfur (Li–S) batteries are promising alternatives of conventional Li‐ion batteries attributed to their remarkable energy densities and high sustainability. However, the practical applications of Li–S batteries are hindered by the shuttling effect of lithium polysulfides (LiPSs) on cathode and the Li dendrite formation on anode, which together leads to inferior rate capability and cycling stability. Here, an advanced N‐doped carbon microreactors embedded with abundant Co3O4/ZnO heterojunctions (CZO/HNC) are designed as dual‐functional hosts for synergistic optimization of both S cathode and Li metal anode. Electrochemical characterization and theoretical calculations confirm that CZO/HNC exhibits an optimized band structure that effectively facilitates ion diffusion and promotes bidirectional LiPSs conversion. In addition, the lithiophilic nitrogen dopants and Co3O4/ZnO sites together regulate dendrite‐free Li deposition. The S@CZO/HNC cathode exhibits excellent cycling stability at 2 C with only 0.039% capacity fading per cycle over 1400 cycles, and the symmetrical Li@CZO/HNC cell enables stable Li plating/striping behavior for 400 h. Remarkably, Li‐S full cell using CZO/HNC as both cathode and anode hosts shows an impressive cycle life of over 1000 cycles. This work provides an exemplification of designing high‐performance heterojunctions for simultaneous protection of two electrodes, and will inspire the applications of practical Li–S batteries. [ABSTRACT FROM AUTHOR]

For practical lithium–sulfur batteries (LSBs), the high sulfur loading and lean‐electrolyte are necessary conditions to achieve the high energy density. However, such extreme conditions will cause serious battery performance fading, due to the uncontrolled deposition of Li2S and lithium dendrite growth. Herein, the tiny Co nanoparticles embedded N‐doped carbon@Co9S8 core–shell material (CoNC@Co9S8NC) is designed to address these challenges. The Co9S8NC‐shell effectively captures lithium polysulfides (LiPSs) and electrolyte, and suppresses the lithium dendrite growth. The CoNC‐core not only improves electronic conductivity, but also promotes Li+ diffusion as well as accelerates Li2S deposition/decomposition. Consequently, the cell with CoNC@Co9S8NC modified separator delivers a high specific capacity of 700 mAh g−1 with a low‐capacity decay rate of 0.035% per cycle at 1.0 C after 750 cycles under a sulfur loading of 3.2 mg cm−2 and a E/S ratio of 12 µL mg−1, and a high initial areal capacity of 9.6 mAh cm−2 under a high sulfur loading of 8.8 mg cm−2 and a low E/S ratio of 4.5 µL mg−1. Besides, the CoNC@Co9S8NC exhibits an ultralow overpotential fluctuation of 11 mV at a current density of 0.5 mA cm–2 after 1000 h during a continuous Li plating/striping process. [ABSTRACT FROM AUTHOR]

The targeted synthesis of manganese phosphides with target phase remains a huge challenge because of their various stoichiometries and phase‐dependent physicochemical properties. In this study, phosphorus‐rich MnP, manganese‐rich Mn2P, and their heterostructure MnP–Mn2P nanoparticles evenly dispersed on porous carbon are accurately synthesized by a convenient one‐pot heat treatment of phosphate resin combined with Mn2+. Moreover, their electrochemical properties are systematically investigated as sulfur hosts in lithium–sulfur batteries. Density functional theory calculations demonstrate the superior adsorption, catalysis capabilities, and electrical conductivity of MnP–Mn2P/C, compared with MnP/C and Mn2P/C. The MnP–Mn2P/C@S exhibits an excellent capacity of 763.3 mAh g−1 at 5 C with a capacity decay rate of only 0.013% after 2000 cycles. A phase evolution product (MnS) of MnP–Mn2P/C@S is detected during the catalysis of MnP–Mn2P/C with polysulfides redox through in situ X‐ray diffraction and Raman spectroscopy. At a sulfur loading of up to 8 mg cm−2, the MnP–Mn2P/C@S achieves an area capacity of 6.4 mAh cm−2 at 0.2 C. A pouch cell with the MnP–Mn2P/C@S cathode exhibits an initial energy density of 360 Wh kg−1. [ABSTRACT FROM AUTHOR]

Abstract Lithium–sulfur (Li–S) batteries are promising alternatives of conventional Li‐ion batteries attributed to their remarkable energy densities and high sustainability. However, the practical applications of Li–S batteries are hindered by the shuttling effect of lithium polysulfides (LiPSs) on cathode and the Li dendrite formation on anode, which together leads to inferior rate capability and cycling stability. Here, an advanced N‐doped carbon microreactors embedded with abundant Co3O4/ZnO heterojunctions (CZO/HNC) are designed as dual‐functional hosts for synergistic optimization of both S cathode and Li metal anode. Electrochemical characterization and theoretical calculations confirm that CZO/HNC exhibits an optimized band structure that effectively facilitates ion diffusion and promotes bidirectional LiPSs conversion. In addition, the lithiophilic nitrogen dopants and Co3O4/ZnO sites together regulate dendrite‐free Li deposition. The S@CZO/HNC cathode exhibits excellent cycling stability at 2 C with only 0.039% capacity fading per cycle over 1400 cycles, and the symmetrical Li@CZO/HNC cell enables stable Li plating/striping behavior for 400 h. Remarkably, Li‐S full cell using CZO/HNC as both cathode and anode hosts shows an impressive cycle life of over 1000 cycles. This work provides an exemplification of designing high‐performance heterojunctions for simultaneous protection of two electrodes, and will inspire the applications of practical Li–S batteries.

Abstract For practical lithium–sulfur batteries (LSBs), the high sulfur loading and lean‐electrolyte are necessary conditions to achieve the high energy density. However, such extreme conditions will cause serious battery performance fading, due to the uncontrolled deposition of Li2S and lithium dendrite growth. Herein, the tiny Co nanoparticles embedded N‐doped carbon@Co9S8 core–shell material (CoNC@Co9S8NC) is designed to address these challenges. The Co9S8NC‐shell effectively captures lithium polysulfides (LiPSs) and electrolyte, and suppresses the lithium dendrite growth. The CoNC‐core not only improves electronic conductivity, but also promotes Li+ diffusion as well as accelerates Li2S deposition/decomposition. Consequently, the cell with CoNC@Co9S8NC modified separator delivers a high specific capacity of 700 mAh g−1 with a low‐capacity decay rate of 0.035% per cycle at 1.0 C after 750 cycles under a sulfur loading of 3.2 mg cm−2 and a E/S ratio of 12 µL mg−1, and a high initial areal capacity of 9.6 mAh cm−2 under a high sulfur loading of 8.8 mg cm−2 and a low E/S ratio of 4.5 µL mg−1. Besides, the CoNC@Co9S8NC exhibits an ultralow overpotential fluctuation of 11 mV at a current density of 0.5 mA cm–2 after 1000 h during a continuous Li plating/striping process.

Abstract The targeted synthesis of manganese phosphides with target phase remains a huge challenge because of their various stoichiometries and phase‐dependent physicochemical properties. In this study, phosphorus‐rich MnP, manganese‐rich Mn2P, and their heterostructure MnP–Mn2P nanoparticles evenly dispersed on porous carbon are accurately synthesized by a convenient one‐pot heat treatment of phosphate resin combined with Mn2+. Moreover, their electrochemical properties are systematically investigated as sulfur hosts in lithium–sulfur batteries. Density functional theory calculations demonstrate the superior adsorption, catalysis capabilities, and electrical conductivity of MnP–Mn2P/C, compared with MnP/C and Mn2P/C. The MnP–Mn2P/C@S exhibits an excellent capacity of 763.3 mAh g−1 at 5 C with a capacity decay rate of only 0.013% after 2000 cycles. A phase evolution product (MnS) of MnP–Mn2P/C@S is detected during the catalysis of MnP–Mn2P/C with polysulfides redox through in situ X‐ray diffraction and Raman spectroscopy. At a sulfur loading of up to 8 mg cm−2, the MnP–Mn2P/C@S achieves an area capacity of 6.4 mAh cm−2 at 0.2 C. A pouch cell with the MnP–Mn2P/C@S cathode exhibits an initial energy density of 360 Wh kg−1.

Lithium sulfur (LiS) batteries possess high theoretical capacity and energy density, holding great promise for next generation electronics and electrical vehicles. However, the LiS batteries development is hindered by the shuttle effect and sluggish conversion kinetics of lithium polysulfides (LiPSs). Designing highly polar materials such as metal oxides (MOs) with moderate adsorption and effective catalytic activity is essential to overcome the above issues. To design efficient MOs catalysts, it is critical and necessary to understand the adsorption mechanism and associated catalytic processes of LiPSs. However, most reviews still lack a comprehensive investigation of the basic mechanism and always ignore their in‐depth relationship. In this review, a systematic analysis toward understanding the underlying adsorption and catalytic mechanism in LiS chemistry as well as discussion of the typical works concerning MOs electrocatalysts are provided. Moreover, to improve the sluggish "adsorption‐diffusion‐conversion" process caused by the low conductive nature of MOs, oxygen vacancies and heterostructure engineering are elucidated as the two most effective strategies. The challenges and prospects of MOs electrocatalysts are also provided in the last section. The authors hope this review will provide instructive guidance to design effective catalyst materials and explore practical possibilities for the commercialization of LiS batteries. [ABSTRACT FROM AUTHOR]

Designing dense thick sulfur cathodes to gain high‐volumetric/areal‐capacity lithium–sulfur batteries (LSBs) in lean electrolytes is extremely desired. Nevertheless, the severe Li2S clogging and unclear mechanism seriously hinder its development. Herein, an integrated strategy is developed to manipulate Li2S redox kinetics of CoP/MXene catalyst via electron‐donor Cu doping. Meanwhile a dense S/Cu0.1Co0.9P/MXene cathode (density = 1.95 g cm−3) is constructed, which presents a large volumetric capacity of 1664 Ah L−1 (routine electrolyte) and a high areal capacity of ≈8.3 mAh cm−2 (lean electrolyte of 5.0 µL mgs−1) at 0.1 C. Systematical thermodynamics, kinetics, and theoretical simulation confirm that electron‐donor Cu doping induces the charge accumulation of Co atoms to form more chemical bonding with polysulfides, whereas weakens CoS bonding energy and generates abundant lattice vacancies and active sites to facilitate the diffusion and catalysis of polysulfides/Li2S on electrocatalyst surface, thereby decreasing the diffusion energy barrier and activation energy of Li2S nucleation and dissolution, boosting Li2S redox kinetics, and inhibiting shuttling in the dense thick sulfur cathode. This work deeply understands the atomic‐level manipulation mechanism of Li2S redox kinetics and provides dependable principles for designing high‐volumetric‐energy‐density, lean‐electrolyte LSBs through integrating bidirectional electro‐catalysts with manipulated Li2S redox and dense‐sulfur engineering. [ABSTRACT FROM AUTHOR]

In this work, unique Co3O4/N‐doped reduced graphene oxide (Co3O4/N‐rGO) composites as favorable sulfur immobilizers and promoters for lithium–sulfur (Li–S) batteries are developed. The prepared Co3O4 nanopolyhedrons (Co3O4‐NP) and Co3O4 nanocubes mainly expose (112) and (001) surfaces, respectively, with different atomic configurations of Co2+/Co3+ sites. Experiments and theoretical calculations confirm that the octahedral coordination Co3+ (Co3+Oh) sites with different oxidation states from tetrahedral coordination Co2+ sites optimize the adsorption and catalytic conversion of lithium polysulfides. Specially, the Co3O4‐NP crystals loaded on N‐rGO expose (112) planes with ample Co3+Oh active sites, exhibiting stronger adsorbability and superior catalytic activity for polysulfides, thus inhibiting the shuttle effect. Therefore, the S@Co3O4‐NP/N‐rGO cathodes deliver excellent electrochemical properties, for example, stable cyclability at 1 C with a low capacity decay rate of 0.058% over 500 cycles, superb rate capability up to 3 C, and high areal capacity of 4.1 mAh cm−2. This catalyst's design incorporating crystal surface engineering and oxidation state regulation strategies also provides new approaches for addressing the complicated issues of Li–S batteries. [ABSTRACT FROM AUTHOR]

Constructing intimate coupling between transition metal and carbon nanomaterials is an effective means to achieve strong immobilization of lithium polysulfides (LiPSs) in the applications of lithium–sulfur (LiS) batteries. Herein, a universal spinning‐coordinating strategy of constructing continuous metal–nitrogen–carbon (MNC, M = Co, Fe, Ni) heterointerface is reported to covalently bond metal nanoparticles with nitrogen‐doped porous carbon fibers (denoted as M/MN@NPCF). Guided by theoretical simulations, the Co/CoN@NPCF hybrid is synthesized as a proof of concept and used as an efficient sulfur host material. The polarized CoNC bridging bonds can induce rapid electron transfer from Co nanoparticles to the NPCF skeleton, promoting the chemical anchoring of LiPSs to improve sulfur utilization. Hence, the as‐assembled LiS battery presents a remarkable capacity of 781 mAh g−1 at 2.0 C and a prominent cycling lifespan with a low decay rate of only 0.032% per cycle. Additionally, a well‐designed Co/CoN@NPCF‐S electrode with a high sulfur loading of 7.1 mg cm−2 is further achieved by 3D printing technique, which demonstrates an excellent areal capacity of 6.4 mAh cm−2 at 0.2 C under a lean‐electrolyte condition. The acquired insights into strongly coupled continuous heterointerface in this work pave the way for rational designs of host materials in LiS systems. [ABSTRACT FROM AUTHOR]

Lithium–sulfur batteries (LSBs) with extremely‐high theoretical energy density (2600 Wh kg−1) are deemed to be the most likely energy storage system to be commercialized. However, the polysulfides shuttling and lithium (Li) metal anode failure in LSBs limit its further commercialization. Herein, a versatile asymmetric separator and a Li‐rich lithium–magnesium (Li–Mg) alloy anode are applied in LSBs. The asymmetric separator is consisted of lithiated‐sulfonated porous organic polymer (SPOP‐Li) and Li6.75La3Zr1.75Nb0.25O12 (LLZNO) layers toward the cathode and anode, respectively. SPOP‐Li serves as a polysulfides barrier and Li‐ion conductor, while the LLZNO functions as an "ion redistributor". Combining with a stable Li–Mg alloy anode, the symmetric cell achieves 5300 h of Li stripping/plating and the modified LSBs exhibit a long lifespan with an ultralow fading rate of 0.03% per cycle for over 1000 cycles at 5 C. Impressively, even under a high‐sulfur‐loading (6.1 mg cm−2), an area capacity of 4.34 mAh cm−2 after 100 cycles can still be maintained, demonstrating high potential for practical application. [ABSTRACT FROM AUTHOR]

Abstract Designing dense thick sulfur cathodes to gain high‐volumetric/areal‐capacity lithium–sulfur batteries (LSBs) in lean electrolytes is extremely desired. Nevertheless, the severe Li2S clogging and unclear mechanism seriously hinder its development. Herein, an integrated strategy is developed to manipulate Li2S redox kinetics of CoP/MXene catalyst via electron‐donor Cu doping. Meanwhile a dense S/Cu0.1Co0.9P/MXene cathode (density = 1.95 g cm−3) is constructed, which presents a large volumetric capacity of 1664 Ah L−1 (routine electrolyte) and a high areal capacity of ≈8.3 mAh cm−2 (lean electrolyte of 5.0 µL mgs−1) at 0.1 C. Systematical thermodynamics, kinetics, and theoretical simulation confirm that electron‐donor Cu doping induces the charge accumulation of Co atoms to form more chemical bonding with polysulfides, whereas weakens CoS bonding energy and generates abundant lattice vacancies and active sites to facilitate the diffusion and catalysis of polysulfides/Li2S on electrocatalyst surface, thereby decreasing the diffusion energy barrier and activation energy of Li2S nucleation and dissolution, boosting Li2S redox kinetics, and inhibiting shuttling in the dense thick sulfur cathode. This work deeply understands the atomic‐level manipulation mechanism of Li2S redox kinetics and provides dependable principles for designing high‐volumetric‐energy‐density, lean‐electrolyte LSBs through integrating bidirectional electro‐catalysts with manipulated Li2S redox and dense‐sulfur engineering.

Abstract In this work, unique Co3O4/N‐doped reduced graphene oxide (Co3O4/N‐rGO) composites as favorable sulfur immobilizers and promoters for lithium–sulfur (Li–S) batteries are developed. The prepared Co3O4 nanopolyhedrons (Co3O4‐NP) and Co3O4 nanocubes mainly expose (112) and (001) surfaces, respectively, with different atomic configurations of Co2+/Co3+ sites. Experiments and theoretical calculations confirm that the octahedral coordination Co3+ (Co3+Oh) sites with different oxidation states from tetrahedral coordination Co2+ sites optimize the adsorption and catalytic conversion of lithium polysulfides. Specially, the Co3O4‐NP crystals loaded on N‐rGO expose (112) planes with ample Co3+Oh active sites, exhibiting stronger adsorbability and superior catalytic activity for polysulfides, thus inhibiting the shuttle effect. Therefore, the S@Co3O4‐NP/N‐rGO cathodes deliver excellent electrochemical properties, for example, stable cyclability at 1 C with a low capacity decay rate of 0.058% over 500 cycles, superb rate capability up to 3 C, and high areal capacity of 4.1 mAh cm−2. This catalyst's design incorporating crystal surface engineering and oxidation state regulation strategies also provides new approaches for addressing the complicated issues of Li–S batteries.

Abstract Lithium–sulfur batteries (LSBs) with extremely‐high theoretical energy density (2600 Wh kg−1) are deemed to be the most likely energy storage system to be commercialized. However, the polysulfides shuttling and lithium (Li) metal anode failure in LSBs limit its further commercialization. Herein, a versatile asymmetric separator and a Li‐rich lithium–magnesium (Li–Mg) alloy anode are applied in LSBs. The asymmetric separator is consisted of lithiated‐sulfonated porous organic polymer (SPOP‐Li) and Li6.75La3Zr1.75Nb0.25O12 (LLZNO) layers toward the cathode and anode, respectively. SPOP‐Li serves as a polysulfides barrier and Li‐ion conductor, while the LLZNO functions as an “ion redistributor”. Combining with a stable Li–Mg alloy anode, the symmetric cell achieves 5300 h of Li stripping/plating and the modified LSBs exhibit a long lifespan with an ultralow fading rate of 0.03% per cycle for over 1000 cycles at 5 C. Impressively, even under a high‐sulfur‐loading (6.1 mg cm−2), an area capacity of 4.34 mAh cm−2 after 100 cycles can still be maintained, demonstrating high potential for practical application.

Abstract Constructing intimate coupling between transition metal and carbon nanomaterials is an effective means to achieve strong immobilization of lithium polysulfides (LiPSs) in the applications of lithium–sulfur (LiS) batteries. Herein, a universal spinning‐coordinating strategy of constructing continuous metal–nitrogen–carbon (MNC, M = Co, Fe, Ni) heterointerface is reported to covalently bond metal nanoparticles with nitrogen‐doped porous carbon fibers (denoted as M/MN@NPCF). Guided by theoretical simulations, the Co/CoN@NPCF hybrid is synthesized as a proof of concept and used as an efficient sulfur host material. The polarized CoNC bridging bonds can induce rapid electron transfer from Co nanoparticles to the NPCF skeleton, promoting the chemical anchoring of LiPSs to improve sulfur utilization. Hence, the as‐assembled LiS battery presents a remarkable capacity of 781 mAh g−1 at 2.0 C and a prominent cycling lifespan with a low decay rate of only 0.032% per cycle. Additionally, a well‐designed Co/CoN@NPCF‐S electrode with a high sulfur loading of 7.1 mg cm−2 is further achieved by 3D printing technique, which demonstrates an excellent areal capacity of 6.4 mAh cm−2 at 0.2 C under a lean‐electrolyte condition. The acquired insights into strongly coupled continuous heterointerface in this work pave the way for rational designs of host materials in LiS systems.

MoS2/C composites constructed with van der Waals forces have been extensively applied in lithium–sulfur (Li–S) batteries. However, the catalytic conversion effect on polysulfides is limited because the weak electronic interactions between the composite interfaces cannot fundamentally improve the intrinsic electronic conductivity of MoS2. Herein, density functional theory calculations reveal that the MoS2 and nitrogen‐doped carbon composite with an Mo–O–C bond can promote the catalytic conversion of polysulfides with a Gibbs free energy of only 0.19 eV and a low dissociation energy barrier of 0.48 eV, owing to the strong covalent coupling effect on the heterogeneous interface. Guided by theoretical calculations, a robust MoS2 strongly coupled with a 3D carbon matrix composed of nitrogen‐doped reduced graphene oxide and carbonized melamine foam is designed and constructed as a multifunctional coating layer for lithium–sulfur batteries. As a result, excellent electrochemical performance is achieved for Li–S batteries, with a capacity of 615 mAh g–1 at 5 C, an areal capacity of 6.11 mAh cm–2, and a low self‐discharge of only 8.6% by resting for five days at 0.5 C. This study opens a new avenue for designing 2D material composites toward promoted catalytic conversion of polysulfides. [ABSTRACT FROM AUTHOR]

Lithium‐sulfur (Li–S) batteries are promising as next‐generation energy storage systems. Adsorbents for sulfide species are favorably applied to the cathode, but this substrate often results in a surface‐passivating lithium sulfide(Li2S) film with a strong adsorption of Li2S. Here, an amorphous titanium suboxide (a‐TiOx) is presented that strongly adsorbs lithium polysulfides (Li2Sx, x < 6) but relatively weakly adsorbs to Li2S. With these characteristics, the a‐TiOx achieves high conversion of Li2Sx and high sulfur utilization accompanying the growth of particulate Li2S. The DFT calculations present a mechanism for particulate growth driven by the promoted diffusion and favorable clustering of Li2S. The a‐TiOx‐coated carbon nanotube‐assembled film (CNTF) cathode substrate cell achieves a high discharge capacity equivalent to 90% sulfur utilization at 0.2 C. The cell also delivers a high capacity of 850 mAh g–1 even at the ultra‐high‐speed of 10 C and also exhibits high stability of capacity loss of 0.0226% per cycle up to 500 cycles. The a‐TiOx/CNTF is stacked to achieve a high loading of 7.5 mg S cm–2, achieving a practical areal capacity of 10.1 mAh cm–2. [ABSTRACT FROM AUTHOR]

Exploring new materials and methods to achieve high utilization of sulfur with lean electrolyte is still a common concern in lithium‐sulfur batteries. Here, high‐density oxygen doping chemistry is introduced for making highly conducting, chemically stable sulfides with a much higher affinity to lithium polysulfides. It is found that doping large amounts of oxygen into NiCo2S4 is feasible and can make it outperform the pristine oxides and natively oxidized sulfides. Taking the advantages of high conductivity, chemical stability, the introduced large Li–O interactions, and activated Co (Ni) facets for catalyzing Sn2–, the NiCo2(O–S)4 is able to accelerate the Li2S‐S8 redox kinetics. Specifically, lithium‐sulfur batteries using free‐standing NiCo2(O–S)4 paper and interlayer exhibit the highest capacity of 8.68 mAh cm–2 at 1.0 mA cm–2 even with a sulfur loading of 8.75 mg cm–2 and lean electrolyte of 3.8 µL g–1. The high‐density oxygen doping chemistry can be also applied to other metal compounds, suggesting a potential way for developing more powerful catalysts towards high performance of Li–S batteries. [ABSTRACT FROM AUTHOR]

Abstract Exploring new materials and methods to achieve high utilization of sulfur with lean electrolyte is still a common concern in lithium‐sulfur batteries. Here, high‐density oxygen doping chemistry is introduced for making highly conducting, chemically stable sulfides with a much higher affinity to lithium polysulfides. It is found that doping large amounts of oxygen into NiCo2S4 is feasible and can make it outperform the pristine oxides and natively oxidized sulfides. Taking the advantages of high conductivity, chemical stability, the introduced large Li–O interactions, and activated Co (Ni) facets for catalyzing Sn2–, the NiCo2(O–S)4 is able to accelerate the Li2S‐S8 redox kinetics. Specifically, lithium‐sulfur batteries using free‐standing NiCo2(O–S)4 paper and interlayer exhibit the highest capacity of 8.68 mAh cm–2 at 1.0 mA cm–2 even with a sulfur loading of 8.75 mg cm–2 and lean electrolyte of 3.8 µL g–1. The high‐density oxygen doping chemistry can be also applied to other metal compounds, suggesting a potential way for developing more powerful catalysts towards high performance of Li–S batteries.

Lithium–sulfur batteries possess high theoretical energy density but suffer from rapid capacity fade due to the shuttling and sluggish conversion of polysulfides. Aiming at these problems, a biomimetic design of cofactor‐assisted artificial enzyme catalyst, melamine (MM) crosslinked hemin on carboxylated carbon nanotubes (CNTs) (i.e., [CNTs–MM–hemin]), is presented to efficiently convert polysulfides. The MM cofactors bind with the hemin artificial enzymes and CNT conductive substrates through FeN5 coordination and/or covalent amide bonds to provide high and durable catalytic activity for polysulfide conversions, while π–π conjugations between hemin and CNTs and multiple Li‐bond networks offered by MM endow the cathode with good electronic/Li+ transmission ability. This synergistic mechanism enables rapid sulfur reaction kinetics, alleviated polysulfide shuttling, and an ultralow (<1.3%) loss of hemin active sites in electrolyte, which is ≈60 times lower than those of noncovalent crosslinked samples. As a result, the Li–S battery using [CNTs–MM–hemin] cathode retains a capacity of 571 mAh g−1 after 900 cycles at 1C with an ultralow capacity decay rate of 0.046% per cycle. Even under raising sulfur loadings up to 7.5 mg cm−2, the cathode still can steadily run 110 cycles with a capacity retention of 83%. [ABSTRACT FROM AUTHOR]

Lithium–sulfur (Li–S) battery is identified as one of the most promising next‐generation energy storage systems due to its ultra‐high theoretical energy density up to 2600 Wh kg−1. However, Li metal anode suffers from dramatic volume change during cycling, continuous corrosion by polysulfide electrolyte, and dendrite formation, rendering limited cycling lifespan. Considering Li metal anode as a double‐edged sword that contributes to ultrahigh energy density as well as limited cycling lifespan, it is necessary to evaluate Li‐based alloy as anode materials to substitute Li metal for high‐performance Li–S batteries. In this contribution, the authors systematically evaluate the potential and feasibility of using Li metal or Li‐based alloys to construct Li–S batteries with an actual energy density of 500 Wh kg−1. A quantitative analysis method is proposed by evaluating the required amount of electrolyte for a targeted energy density. Based on a three‐level (ideal material level, practical electrode level, and pouch cell level) analysis, highly lithiated lithium–magnesium (Li–Mg) alloy is capable to achieve 500 Wh kg−1 Li–S batteries besides Li metal. Accordingly, research on Li–Mg and other Li‐based alloys are reviewed to inspire a promising pathway to realize high‐energy‐density and long‐cycling Li–S batteries. [ABSTRACT FROM AUTHOR]

Lithium–sulfur batteries (LSBs) hold great promise as one of the next‐generation power supplies for portable electronics and electric vehicles due to their ultrahigh energy density, cost effectiveness, and environmental benignity. However, their practical application has been impeded owing to the electronic insulation of sulfur and its intermediates, serious shuttle effect, large volume variation, and uncontrollable formation of lithium dendrites. Over the past decades, many pioneering strategies have been developed to address these issues via improving electrodes, electrolytes, separators and binders. Remarkably, polymers can be readily applied to all these aspects due to their structural designability, functional versatility, superior chemical stability and processability. Moreover, their lightweight and rich resource characteristics enable the production of LSBs with high‐volume energy density at low cost. Surprisingly, there have been few reviews on development of polymers in LSBs. Herein, breakthroughs and future perspectives of emerging polymers in LSBs are scrutinized. Significant attention is centered on recent implementation of polymers in each component of LSBs with an emphasis on intrinsic mechanisms underlying their specific functions. The review offers a comprehensive overview of state‐of‐the‐art polymers for LSBs, provides in‐depth insights into addressing key challenges, and affords important resources for researchers working on electrochemical energy systems. [ABSTRACT FROM AUTHOR]

Sluggish sulfur reduction and lithium sulfide (Li2S) oxidation prevent the widespread use of lithium–sulfur (Li–S) batteries, which are attractive alternatives to Li−ion batteries. The authors propose that a transition metal selenide heterojunction (CoSe–ZnSe) catalytically accelerates bidirectional sulfur conversion reactions. A combination of synchrotron X‐ray absorption spectroscopy and density functional theory calculations show that a highly active heterointerface with charge redistribution and structure distortion effectively immobilizes sulfur species, facilitates Li ion diffusion, and decreases the sulfur reduction and Li2S oxidation energy barriers. The CoSe–ZnSe catalytic cathode exhibits high areal capacities, good rate capability, and superior cycling stability with capacity fading rate of 0.027% per cycle over 1700 cycles. Furthermore, CoSe–ZnSe heterojunctions anchored on graphene aerogels (CoSe–ZnSe@G) enhance ionic transport and catalytic activity under high sulfur loading and lean electrolyte conditions. A high areal capacity of 8.0 mAh cm−2 is achieved at an electrolyte/sulfur ratio of 3 µL mg−1. This study demonstrates the importance of bidirectional catalytic heterojunctions and structure engineering in boosting Li–S battery performances. [ABSTRACT FROM AUTHOR]

The sulfur redox kinetics critically matters to superior lithium–sulfur (Li–S) batteries, for which single atom catalysts (SACs) take effect on promoting Li2S redox process and mitigating the shuttle behavior of lithium polysulfide (LiPs). However, conventional trial‐and‐error strategy significantly slows down the development of SACs in Li–S batteries. Here, the Li2S oxidation processes over MN4@G catalysts are fully explored and energy barrier of Li2S decomposition (Eb) is identified to correlate strongly with three parameters of energy difference between initial and final states of Li2S decomposition, reaction energy of Li2S oxidation and LiS bond strength. These three parameters can serve as efficient descriptors by which two excellent SACs of MoN4@G and WN4@G are screened which give rise to Eb values of 0.58 and 0.55 eV, respectively, outperforming other analogues in adsorbing LiPs and accelerating the redox kinetics of Li2S. This method can be extended to a wider range of SACs by coupling MN4 moiety with heterostructures and heteroatoms beyond N where WN4@G/TiS2 heterointerface is predicted to exhibit enhanced catalytic performance for Li2S decomposition with Eb of 0.40 eV. This work will help accelerate the process of designing a wider range of efficient catalysts in Li–S batteries and even beyond, e.g. alkali‐ion‐Chalcogen batteries. [ABSTRACT FROM AUTHOR]

Abstract Sluggish sulfur reduction and lithium sulfide (Li2S) oxidation prevent the widespread use of lithium–sulfur (Li–S) batteries, which are attractive alternatives to Li−ion batteries. The authors propose that a transition metal selenide heterojunction (CoSe–ZnSe) catalytically accelerates bidirectional sulfur conversion reactions. A combination of synchrotron X‐ray absorption spectroscopy and density functional theory calculations show that a highly active heterointerface with charge redistribution and structure distortion effectively immobilizes sulfur species, facilitates Li ion diffusion, and decreases the sulfur reduction and Li2S oxidation energy barriers. The CoSe–ZnSe catalytic cathode exhibits high areal capacities, good rate capability, and superior cycling stability with capacity fading rate of 0.027% per cycle over 1700 cycles. Furthermore, CoSe–ZnSe heterojunctions anchored on graphene aerogels (CoSe–ZnSe@G) enhance ionic transport and catalytic activity under high sulfur loading and lean electrolyte conditions. A high areal capacity of 8.0 mAh cm−2 is achieved at an electrolyte/sulfur ratio of 3 µL mg−1. This study demonstrates the importance of bidirectional catalytic heterojunctions and structure engineering in boosting Li–S battery performances.

Abstract Lithium–sulfur batteries (LSBs) hold great promise as one of the next‐generation power supplies for portable electronics and electric vehicles due to their ultrahigh energy density, cost effectiveness, and environmental benignity. However, their practical application has been impeded owing to the electronic insulation of sulfur and its intermediates, serious shuttle effect, large volume variation, and uncontrollable formation of lithium dendrites. Over the past decades, many pioneering strategies have been developed to address these issues via improving electrodes, electrolytes, separators and binders. Remarkably, polymers can be readily applied to all these aspects due to their structural designability, functional versatility, superior chemical stability and processability. Moreover, their lightweight and rich resource characteristics enable the production of LSBs with high‐volume energy density at low cost. Surprisingly, there have been few reviews on development of polymers in LSBs. Herein, breakthroughs and future perspectives of emerging polymers in LSBs are scrutinized. Significant attention is centered on recent implementation of polymers in each component of LSBs with an emphasis on intrinsic mechanisms underlying their specific functions. The review offers a comprehensive overview of state‐of‐the‐art polymers for LSBs, provides in‐depth insights into addressing key challenges, and affords important resources for researchers working on electrochemical energy systems.

Abstract Lithium–sulfur (Li–S) battery is identified as one of the most promising next‐generation energy storage systems due to its ultra‐high theoretical energy density up to 2600 Wh kg−1. However, Li metal anode suffers from dramatic volume change during cycling, continuous corrosion by polysulfide electrolyte, and dendrite formation, rendering limited cycling lifespan. Considering Li metal anode as a double‐edged sword that contributes to ultrahigh energy density as well as limited cycling lifespan, it is necessary to evaluate Li‐based alloy as anode materials to substitute Li metal for high‐performance Li–S batteries. In this contribution, the authors systematically evaluate the potential and feasibility of using Li metal or Li‐based alloys to construct Li–S batteries with an actual energy density of 500 Wh kg−1. A quantitative analysis method is proposed by evaluating the required amount of electrolyte for a targeted energy density. Based on a three‐level (ideal material level, practical electrode level, and pouch cell level) analysis, highly lithiated lithium–magnesium (Li–Mg) alloy is capable to achieve 500 Wh kg−1 Li–S batteries besides Li metal. Accordingly, research on Li–Mg and other Li‐based alloys are reviewed to inspire a promising pathway to realize high‐energy‐density and long‐cycling Li–S batteries.

Abstract Lithium–sulfur batteries possess high theoretical energy density but suffer from rapid capacity fade due to the shuttling and sluggish conversion of polysulfides. Aiming at these problems, a biomimetic design of cofactor‐assisted artificial enzyme catalyst, melamine (MM) crosslinked hemin on carboxylated carbon nanotubes (CNTs) (i.e., [CNTs–MM–hemin]), is presented to efficiently convert polysulfides. The MM cofactors bind with the hemin artificial enzymes and CNT conductive substrates through FeN5 coordination and/or covalent amide bonds to provide high and durable catalytic activity for polysulfide conversions, while π–π conjugations between hemin and CNTs and multiple Li‐bond networks offered by MM endow the cathode with good electronic/Li+ transmission ability. This synergistic mechanism enables rapid sulfur reaction kinetics, alleviated polysulfide shuttling, and an ultralow (

Abstract The sulfur redox kinetics critically matters to superior lithium–sulfur (Li–S) batteries, for which single atom catalysts (SACs) take effect on promoting Li2S redox process and mitigating the shuttle behavior of lithium polysulfide (LiPs). However, conventional trial‐and‐error strategy significantly slows down the development of SACs in Li–S batteries. Here, the Li2S oxidation processes over MN4@G catalysts are fully explored and energy barrier of Li2S decomposition (Eb) is identified to correlate strongly with three parameters of energy difference between initial and final states of Li2S decomposition, reaction energy of Li2S oxidation and LiS bond strength. These three parameters can serve as efficient descriptors by which two excellent SACs of MoN4@G and WN4@G are screened which give rise to Eb values of 0.58 and 0.55 eV, respectively, outperforming other analogues in adsorbing LiPs and accelerating the redox kinetics of Li2S. This method can be extended to a wider range of SACs by coupling MN4 moiety with heterostructures and heteroatoms beyond N where WN4@G/TiS2 heterointerface is predicted to exhibit enhanced catalytic performance for Li2S decomposition with Eb of 0.40 eV. This work will help accelerate the process of designing a wider range of efficient catalysts in Li–S batteries and even beyond, e.g. alkali‐ion‐Chalcogen batteries.

It is of importance to explore a new carbon nanomaterial possessing vital functions to fulfill the high standards for practical achievement of the electromagnetic (EM) barrier for blocking EM waves and the electrochemical (EC) barrier as a functional separator for EC energy storage. Herein, facile synthesis of a new class of carbon nanostructures, which consist of interconnected N‐doped graphitic carbon nanocubes partially embedded by nickel nanoparticles, is described. The hollow interior of graphitic nanocube induces internal reflection of EM waves and confines active materials of EC energy storage. Nitrogen functionalities implanted in graphitic structure enhance electrical conductivity as well as improve chemical interaction with active materials. Furthermore, nickel nanoparticles in graphitic nanocube function as an EM wave‐absorbing material and an electrocatalyst for EC energy storage. Through comprehensive assessments, remarkable performances originating from distinctive nanostructures give new insights into structural design for the carbon nanostructure‐based high‐performance EM and EC barriers. [ABSTRACT FROM AUTHOR]

Abstract It is of importance to explore a new carbon nanomaterial possessing vital functions to fulfill the high standards for practical achievement of the electromagnetic (EM) barrier for blocking EM waves and the electrochemical (EC) barrier as a functional separator for EC energy storage. Herein, facile synthesis of a new class of carbon nanostructures, which consist of interconnected N‐doped graphitic carbon nanocubes partially embedded by nickel nanoparticles, is described. The hollow interior of graphitic nanocube induces internal reflection of EM waves and confines active materials of EC energy storage. Nitrogen functionalities implanted in graphitic structure enhance electrical conductivity as well as improve chemical interaction with active materials. Furthermore, nickel nanoparticles in graphitic nanocube function as an EM wave‐absorbing material and an electrocatalyst for EC energy storage. Through comprehensive assessments, remarkable performances originating from distinctive nanostructures give new insights into structural design for the carbon nanostructure‐based high‐performance EM and EC barriers.

Abstract Structural design of advanced cathodes is a promising strategy to suppress the shuttle effect for lithium‐sulfur batteries (LSBs). In this work, the carbon cloth covered with CoS2 nanoparticles (CC‐CoS2) is prepared to function as both three‐dimensional (3D) current collector and physicochemical barrier to retard migration of soluble lithium polysulfides. On the one hand, the CC‐CoS2 film works as a robust 3D current collector and host with high conductivity, high sulfur loading, and high capability of capturing polysulfides. On the other hand, the 3D porous CC‐CoS2 film serves as a multifunctional interlayer that exhibits efficient physical blocking, strong chemisorption, and fast catalytic redox reaction kinetics toward soluble polysulfides. Consequently, the Al@S/AB@CC‐CoS2 cell with a sulfur loading of 1.2 mg cm−2 exhibits a high rate capability (≈823 mAh g−1 at 4 C) and delivers excellent capacity retention (a decay of ≈0.021% per cycle for 1000 cycles at 4 C). Moreover, the sandwiched cathode of CC‐CoS2@S/AB@CC‐CoS2 is designed for high sulfur loading LSBs. The CC‐CoS2@S/AB@CC‐CoS2 cells with sulfur loadings of 4.2 and 6.1 mg cm−2 deliver high reversible capacities of 1106 and 885 mAh g−1, respectively, after 100 cycles at 0.2 C. The outstanding electrochemical performance is attributed to the sandwiched structure with active catalytic component.

Structural design of advanced cathodes is a promising strategy to suppress the shuttle effect for lithium‐sulfur batteries (LSBs). In this work, the carbon cloth covered with CoS2 nanoparticles (CC‐CoS2) is prepared to function as both three‐dimensional (3D) current collector and physicochemical barrier to retard migration of soluble lithium polysulfides. On the one hand, the CC‐CoS2 film works as a robust 3D current collector and host with high conductivity, high sulfur loading, and high capability of capturing polysulfides. On the other hand, the 3D porous CC‐CoS2 film serves as a multifunctional interlayer that exhibits efficient physical blocking, strong chemisorption, and fast catalytic redox reaction kinetics toward soluble polysulfides. Consequently, the Al@S/AB@CC‐CoS2 cell with a sulfur loading of 1.2 mg cm−2 exhibits a high rate capability (≈823 mAh g−1 at 4 C) and delivers excellent capacity retention (a decay of ≈0.021% per cycle for 1000 cycles at 4 C). Moreover, the sandwiched cathode of CC‐CoS2@S/AB@CC‐CoS2 is designed for high sulfur loading LSBs. The CC‐CoS2@S/AB@CC‐CoS2 cells with sulfur loadings of 4.2 and 6.1 mg cm−2 deliver high reversible capacities of 1106 and 885 mAh g−1, respectively, after 100 cycles at 0.2 C. The outstanding electrochemical performance is attributed to the sandwiched structure with active catalytic component. [ABSTRACT FROM AUTHOR]

Abstract Rational construction of sulfur electrodes is essential in pursuit of practically viable lithium–sulfur (Li–S) batteries. Herein, bimetallic NiCo‐layered double hydroxide (NiCo‐LDH) with a unique hierarchical micro‐nano architecture is developed as an advanced sulfur reservoir for Li–S batteries. Compared with the monometallic Co‐layered double hydroxide (Co‐LDH) counterpart, the bimetallic configuration realizes much enriched, miniaturized, and vertically aligned LDH nanosheets assembled in hollow polyhedral nanoarchitecture, which geometrically benefits the interface exposure for host–guest interactions. Beyond that, the introduction of secondary metal intensifies the chemical interactions between layered double hydroxide (LDH) and sulfur species, which implements strong sulfur immobilization and catalyzation for rapid and durable sulfur electrochemistry. Furthermore, the favorable NiCo‐LDH is architecturally upgraded into closely packed micro‐nano clusters with facilitated long‐range electron/ion conduction and robust structural integrity. Due to these attributes, the corresponding Li–S cells realize excellent cyclability over 800 cycles with a minimum capacity fading of 0.04% per cycle and good rate capability up to 2 C. Moreover, highly reversible areal capacity of 4.3 mAh cm−2 can be achieved under a raised sulfur loading of 5.5 mg cm−2. This work provides not only an effective architectural design but also a deepened understanding on bimetallic LDH sulfur reservoir for high‐performance Li–S batteries.

Rational construction of sulfur electrodes is essential in pursuit of practically viable lithium–sulfur (Li–S) batteries. Herein, bimetallic NiCo‐layered double hydroxide (NiCo‐LDH) with a unique hierarchical micro‐nano architecture is developed as an advanced sulfur reservoir for Li–S batteries. Compared with the monometallic Co‐layered double hydroxide (Co‐LDH) counterpart, the bimetallic configuration realizes much enriched, miniaturized, and vertically aligned LDH nanosheets assembled in hollow polyhedral nanoarchitecture, which geometrically benefits the interface exposure for host–guest interactions. Beyond that, the introduction of secondary metal intensifies the chemical interactions between layered double hydroxide (LDH) and sulfur species, which implements strong sulfur immobilization and catalyzation for rapid and durable sulfur electrochemistry. Furthermore, the favorable NiCo‐LDH is architecturally upgraded into closely packed micro‐nano clusters with facilitated long‐range electron/ion conduction and robust structural integrity. Due to these attributes, the corresponding Li–S cells realize excellent cyclability over 800 cycles with a minimum capacity fading of 0.04% per cycle and good rate capability up to 2 C. Moreover, highly reversible areal capacity of 4.3 mAh cm−2 can be achieved under a raised sulfur loading of 5.5 mg cm−2. This work provides not only an effective architectural design but also a deepened understanding on bimetallic LDH sulfur reservoir for high‐performance Li–S batteries. [ABSTRACT FROM AUTHOR]

Abstract The shuttle effect of soluble lithium polysulfides during the charge/discharge process is the key bottleneck hindering the practical application of lithium–sulfur batteries. Herein, a multifunctional interlayer is developed by growing metallic molybdenum disulfide nanosheets on both outer and inner walls of cotton cloth derived carbon microtube textile (MoS2@CMT). The hollow structure of CMT provides channels to favor electrolyte penetration, Li+ diffusion and restrains polysulfides via physical confinement. The hydrophilic and conductive 1T‐MoS2 nanosheets facilitate chemisorption and kinetic behavior of polysulfides. The synergic effect of 1T‐MoS2 nanosheets and CMT affords the MoS2@CMT interlayer with an efficient trapping‐diffusion‐conversion ability toward polysulfides. Therefore, the cell with the MoS2@CMT interlayer exhibits enhanced cycling life (765 mAh g−1 after 500 cycles at 0.5 C) and rate performance (974 mAh g−1 at 2 C and 740 mAh g−1 at 5 C). This study presents a pathway to develop low‐cost multifunctional interlayers for advanced lithium–sulfur batteries.

Abstract For high‐energy lithium–sulfur batteries, the poor volumetric energy density is a bottleneck as compared with lithium–ion batteries, due to the low density of both the sulfur active material and sulfur host. Herein, in order to enhance the volumetric energy density of sulfur cathode, a universal approach is proposed to fabricate a compact sulfur cathode with dense materials as sulfur host, instead of the old‐fashioned lightweight carbon nanomaterials. Based on this strategy, heavy lanthanum strontium manganese oxide (La0.8Sr0.2MnO3), with a high theoretical density of up to 6.5 g cm−3, is introduced as sulfur host. Meanwhile, the La0.8Sr0.2MnO3 host also acts as an efficient electrocatalyst to accelerate the diffusion, adsorption, and redox dynamics of lithium polysulfides in the charge–discharge processes. As a result, such S/La0.8Sr0.2MnO3 cathode presents high gravimetric/volumetric capacity and outstanding cycling stability. Moreover, an ultra‐high volumetric energy density of 2727 Wh L−1‐cathode is achieved based on the densification effect with higher density (1.69 g cm−3), which is competitive to the Ni‐rich oxide cathode (1800–2160 Wh L−1) of lithium–ion batteries. The current study opens up a path for constructing high volumetric capacity sulfur cathode with heavy and catalytic host toward practical applications of lithium–sulfur batteries.

Abstract Lean electrolyte (small E/S ratio) is urgently needed to achieve high practical energy densities in Li–S batteries, but there is a distinction between the cathode's absorbed electrolyte (AE) which is cathode‐intrinsic and total added electrolyte (E) which depends on cell geometry. While total pore volume in sulfur cathodes affects AE/S and performance, it is shown here that pore morphology, size, connectivity, and fill factor all matter. Compared to conventional thermally dried sulfur cathodes that usually render “open lakes” and closed pores, a freeze‐dried and compressed (FDS‐C) sulfur cathode is developed with a canal‐capillary pore structure, which exhibits high mean performance and greatly reduces cell‐to‐cell variation, even at high sulfur loading (14.2 mg cm−2) and ultralean electrolyte condition (AE/S = 1.2 µL mg−1). Interestingly, as AE/S is swept from 2 to 1.2 µL mg−1, the electrode pores go from fully flooded to semi‐flooded, and the coin cell still maintains function until (AE/S)min ≈ 1.2 µL mg−1 is reached. When scaled up to Ah‐level pouch cells, the full‐cell energy density can reach 481 Wh kg−1 as its E/S ≈ AE/S ratio can be reduced to 1.2 µL mg−1, proving high‐performance pouch cells can actually be working in the ultralean, semi‐flooded regime.