Rational Integration of Polypropylene/Graphene Oxide/Nafion as Ternary‐Layered Separator to Retard the Shuttle of Polysulfides for Lithium–Sulfur Batteries

The reversible electrochemical transformation from lithium (Li) and sulfur (S) into Li₂S through multielectron reactions can be utilized in secondary Li–S batteries with very high energy density. However, both the low Coulombic efficiency and severe capacity degradation limits the full utilization of active sulfur, which hinders the practical applications of Li–S battery system. The present study reports a ternary‐layered separator with a macroporous polypropylene (PP) matrix layer, graphene oxide (GO) barrier layer, and Nafion retarding layer as the separator for Li–S batteries with high Coulombic efficiency and superior cyclic stability. In the ternary‐layered separator, ultrathin layer of GO (0.0032 mg cm^?2, estimated to be around 40 layers) blocks the macropores of PP matrix, and a dense ion selective Nafion layer with a very low loading amount of 0.05 mg cm^?2 is attached as a retarding layer to suppress the crossover of sulfur‐containing species. The ternary‐layered separators are effective in improving the initial capacity and the Coulombic efficiency of Li–S cells from 969 to 1057 mAh g^?1, and from 80% to over 95% with an LiNO₃‐free electrolyte, respectively. The capacity degradation is reduced from 0.34% to 0.18% per cycle within 200 cycles when the PP separator is replaced by the ternary‐layered separators. This work provides the rational design strategy for multifunctional separators at cell scale to effective utilizing of active sulfur and retarding of polysulfides, which offers the possibility of high energy density Li–S cells with long cycling life.     

Robust,Ultra‐Tough Flexible Cathodes for High‐Energy Li–S Batteries

Sulfur cathodes have become appealing for rechargeable batteries because of their high theoretical capacity (1675 mA h g^?1). However, the conventional cathode configuration borrowed from lithium‐ion batteries may not allow the pure sulfur cathode to put its unique materials chemistry to good use. The solid_(sulfur)–liquid_{(polysulfides)}–solid_(sulfides) phase transitions generate polysulfide intermediates that are soluble in the commonly used organic solvents in Li–S cells. The resulting severe polysulfide diffusion and the irreversible active‐material loss have been hampering the development of Li–S batteries for years. The present study presents a robust, ultra‐tough, flexible cathode with the active‐material fillings encapsulated between two buckypapers (B), designated as buckypaper/sulfur/buckypaper (B/S/B) cathodes, that suppresses the irreversible polysulfide diffusion to the anode and offers excellent electrochemical reversibility with a low capacity fade rate of 0.06% per cycle after 400 cycles. Engineering enhancements demonstrate that the B/S/B cathodes represent a facile approach for the development of high‐performance sulfur electrodes with a high areal capacity of 5.1 mA h cm^?2, which increases further to approach 7 mA h cm^?2 on coupling with carbon‐coated separators.     

MoS2/Celgard Separator as Efficient Polysulfide Barrier for Long‐Life Lithium–Sulfur Batteries

A high lithium conductive MoS₂/Celgard composite separator is reported as efficient polysulfides barrier in Li–S batteries. Significantly, thanks to the high density of lithium ions on MoS₂ surface, this composite separator shows high lithium conductivity, fast lithium diffusion, and facile lithium transference. When used in Li–S batteries, the separator is proven to be highly efficient for depressing polysulfides shuttle, leading to high and long cycle stability. With 65% of sulfur loading, the device with MoS₂/Celgard separator delivers an initial capacity of 808 mAh g^?1 and a substantial capacity of 401 mAh g^?1 after 600 cycles, corresponding to only 0.083% of capacity decay per cycle that is comparable to the best reported result so far. In addition, the Coulombic efficiency remains more than 99.5% during all 600 cycles, disclosing an efficient ionic sieve preventing polysulfides migration to the anode while having negligible influence on Li⁺ ions transfer across the separator. The strategy demonstrated in this work will open the door toward developing efficient separators with flexible 2D materials beyond graphene for energy‐storage devices.     

A Highly Conductive MOF of Graphene Analogue Ni3(HITP)2 as a Sulfur Host for High‐Performance Lithium–Sulfur Batteries

Lithium–sulfur (Li–S) batteries have been considered as one of the most promising energy storage systems owing to their high theoretical capacity and energy density. However, their commercial applications are obstructed by sluggish reaction kinetics and rapid capacity degradation mainly caused by polysulfide shuttling. Herein, the first attempt to utilize a highly conductive metal–organic framework (MOF) of Ni₃(HITP)₂ graphene analogue as the sulfur host material to trap and transform polysulfides for high‐performance Li–S batteries is made. Besides, the traditional conductive additive acetylene black is replaced by carbon nanotubes to construct matrix conduction networks for triggering the rate and cycling performance of the active cathode. As a result, the S@Ni₃(HITP)₂ with sulfur content of 65.5 wt% shows excellent sulfur utilization, rate performance, and cyclic durability. It delivers a high initial capacity of 1302.9 mAh g^?1 and good capacity retention of 848.9 mAh g^?1 after 100 cycles at 0.2 C. Highly reversible discharge capacities of 807.4 and 629.6 mAh g^?1 are obtained at 0.5 and 1 C for 150 and 300 cycles, respectively. Such kinds of pristine MOFs with high conductivity and abundant polar sites reveal broad promising prospect for application in the field of high‐performance Li–S batteries.     

Design Multifunctional Catalytic Interface: Toward Regulation of Polysulfide and Li2S Redox Conversion in Li–S Batteries

The polysulfide shuttle effect and sluggish reaction kinetics hamper the practical applications of lithium–sulfur (Li–S) batteries. Incorporating a functional interlayer to trapping and binding polysulfides has been found effective to block polysulfide migration. Furthermore, surface chemistry at soluble polysulfides/electrolyte interface is a crucial step for Li–S battery in which stable cycling depends on adsorption and reutilization of blocked polysulfides in the electrolyte. A multifunctional catalytic interface composed of niobium nitride/N‐doped graphene (NbN/NG) along the soluble polysulfides/electrolyte is designed and constructed to regulate corresponding interface chemical reaction, which can afford long‐range electron transfer surfaces, numerous strong chemisorption, and catalytic sites in a working lithium–sulfur battery. Both experimental and theoretical calculation results suggest that a new catalytic interface enabled by metal‐like NbN with superb electrocatalysis anchored on NG is highly effective in regulating the blocked polysulfide redox reaction and tailoring the Li₂S nucleation–growth–decomposition process. Therefore, the Li–S batteries with multifunctional NbN/NG barrier exhibit excellent rate performance (621.2 mAh g^?1 at 3 C) and high stable cycling life (81.5% capacity retention after 400 cycles). This work provides new insights to promote Li–S batteries via multifunctional catalytic interface engineering.     

The Structural and Electronic Engineering of Molybdenum Disulfide Nanosheets as Carbon-Free Sulfur Hosts for Boosting Energy Density and Cycling Life of Lithium–Sulfur Batteries

The compact sulfur cathodes with high sulfur content and high sulfur loading are crucial to promise high energy density of lithium–sulfur (Li–S) batteries. However, some daunting problems, such as low sulfur utilization efficiency, serious polysulfides shuttling, and poor rate performance, are usually accompanied during practical deployment. The sulfur hosts play key roles. Herein, the carbon-free sulfur host composed of vanadium-doped molybdenum disulfide (VMS) nanosheets is reported. Benefiting from the basal plane activation of molybdenum disulfide and structural advantage of VMS, high stacking density of sulfur cathode is allowed for high areal and volumetric capacities of the electrodes together with the effective suppression of polysulfides shuttling and the expedited redox kinetics of sulfur species during cycling. The resultant electrode with high sulfur content of 89 wt.% and high sulfur loading of 7.2 mg cm⁻² achieves high gravimetric capacity of 900.9 mAh g⁻¹, the areal capacity of 6.48 mAh cm⁻², and volumetric capacity of 940 mAh cm⁻³ at 0.5 C. The electrochemical performance can rival with the state-of-the-art those in the reported Li–S batteries. This work provides methodology guidance for the development of the cathode materials to achieve high-energy-density and long-life Li–S batteries.     

Promoting Reversible Redox Kinetics by Separator Architectures Based on CoS2/HPGC Interlayer as Efficient Polysulfide‐Trapping Shield for Li–S Batteries

Main obstacles from the shuttle effect and slow conversion rate of soluble polysulfide compromise the sulfur utilization and cycling life for lithium sulfur (Li–S) batteries. In pursuit of a practically viable high performance Li–S battery, a separator configuration (CoS₂/HPGC/interlayer) as efficient polysulfide trapping barrier is reported. This configuration endows great advantages, particularly enhanced conductivity, promoted polysulfide trapping capability, accelerated sulfur electrochemistry, when using the functional interlayer for Li–S cells. Attributed to the above merits, such cell shows excellent cyclability, with a capacity of 846 mAh g^?1 after 250 cycles corresponding to a high capacity retention of 80.2% at 0.2 C, and 519 mAh g^?1 after 500 cycles at 1C (1C = 1675 mA g^?1). In addition, the optimized separator exhibits a high initial areal capacity of 4.293 mAh cm^?2 at 0.1C. Moreover, with CoS₂/HPGC/interlayer, the sulfur cell enables a low self‐discharge rate with a very high capacity retention of 97.1%. This work presents a structural engineering of the separator toward suppressing the dissolution of soluble Li₂Sn moieties and simultaneously promoting the sulfur conversion kinetics, thus achieving durable and high capacity Li–S batteries.     

Polyethylenimine Expanded Graphite Oxide Enables High Sulfur Loading and Long‐Term Stability of Lithium–Sulfur Batteries

To realize practical lithium–sulfur batteries (LSBs) with long cycling life, designing cathode hosts with a high specific surface area (SSA) is recognized as an efficient way to trap the soluble polysulfides. However, it is also blamed for diminishing the volumetric energy density and being susceptible to side reactions. Herein, polyethylenimine intercalated graphite oxide (PEI‐GO) with a low SSA of 4.6 m² g^?1 and enlarged interlayer spacing of 13 Å is proposed as a superior sulfur host, which enables homogeneous distribution of high sulfur content (73%) and facilitates Li⁺ transfer in thick sulfur electrode. LSBs with a moderate sulfur loading (3.4 mg S cm^?2) achieve an initial capacity of 1157 and 668 mAh g^?1 after 500 cycles at 0.5 C. Even when the sulfur loading is increased to 7.3 mg cm^?2, the electrode still delivers a high areal capacity of 4.7 mAh cm^?2 (641 mAh g^?1) after 200 cycles at 0.2 C. The excellent electrochemical properties of PEI‐GO are mainly attributed to the homogeneous distribution of sulfur in PEI‐GO and the strong chemical interactions between polysulfides and amine groups, which can mitigate the loss of active phases and contribute to the better cycling stability.     

Implanting Atomic Cobalt within Mesoporous Carbon toward Highly Stable Lithium–Sulfur Batteries

Lithium–sulfur (Li–S) batteries hold great promise to serve as next‐generation energy storage devices. However, the practical performances of Li–S batteries are severely limited by the sulfur cathode regarding its low conductivity, huge volume change, and the polysulfide shuttle effect. The first two issues have been well addressed by introducing mesoporous carbon hosts to the sulfur cathode. Unfortunately, the nonpolar nature of carbon materials renders poor affinity to polar polysulfides, leaving the shuttling issue unaddressed. In this contribution, atomic cobalt is implanted within the skeleton of mesoporous carbon via a supramolecular self‐templating strategy, which simultaneously improves the interaction with polysulfides and maintains the mesoporous structure. Moreover, the atomic cobalt dopants serve as active sites to improve the kinetics of the sulfur redox reactions. With the atomic‐cobalt‐decorated mesoporous carbon host, a high capacity of 1130 mAh g_S^?1 at 0.5 C and a high stability with a retention of 74.1% after 300 cycles are realized. Implanting atomic metal in mesoporous carbon demonstrates a feasible strategy to endow nanomaterials with targeted functions for Li–S batteries and broad applications.     

Regulating Electrochemical Kinetics of CoP by Incorporating Oxygen on Surface for High-Performance Li–S Batteries

Lithium–sulfur (Li–S) batteries are widely studied because of their high theoretical specific capacity and environmental friendliness. However, the further development of Li–S batteries is hindered by the shuttle effect of lithium polysulfides (LiPSs) and the sluggish redox kinetics. Since the adsorption and catalytic conversion of LiPSs mainly occur on the surface of the electrocatalyst, regulating the surface structure of electrocatalysts is an advisable strategy to solve the obstacles in Li–S batteries. Herein, CoP nanoparticles with high oxygen content on surface embedded in hollow carbon nanocages (C/O-CoP) is employed to functionalize the separators and the effect of the surface oxygen content of CoP on the electrochemical performance is systematically explored. Increasing the oxygen content on CoP surface can enhance the chemical adsorption to lithium polysulfides and accelerate the redox conversions kinetics of polysulfides. The cell with C/O-CoP modified separator can achieve the capacity of 1033 mAh g⁻¹ and maintain 749 mAh g⁻¹ after 200 cycles at 2 C. Moreover, DFT calculations are used to reveal the enhancement mechanism of oxygen content on surface of CoP in Li–S chemistry. This work offers a new insight into developing high-performance Li–S batteries from the perspective of surface engineering.     

Integration of Binary Active Sites: Co3V2O8 as Polysulfide Traps and Catalysts for Lithium‐Sulfur Battery with Superior Cycling Stability

Lithium‐sulfur (Li‐S) batteries as a promising energy storage candidate have attracted attention due to their high energy density (2600 Wh kg^?1). However, the serious shuttle effect caused by the dissolution of the lithium polysulfides (LiPS) in electrolyte significantly degrades their cycling life and rate performance. Herein, the “binary active sites” concept in a Li‐S battery system via the design of a cobalt vanadium oxide (CVO) modified multifunctional separator is designed. In the case of CVO, active vanadium sites simultaneously anchor the LiPS through the chemical affinity and active cobalt sites can dominate a rapid kinetic conversion. Such a synergistic effect contributes to improving the utilization of sulfur in the electrochemical process for the enhanced electrochemical performance. As a result, the Li‐S battery with the CVO modified separator possesses a high reversible capacity of 1585.5 mAh g^?1 at 0.1 C and superior cycling stability with 0.012% capacity decay cycle^?1 after 3000 cycles. More impressively, the assembled soft‐packaged Li‐S devices can exhibit the excellent stability under bending states. This binary active sites strategy provides a route to design the functional materials for modifying separators of Li‐S batteries to improve the performance.     

Pyrrolic‐Type Nitrogen‐Doped Hierarchical Macro/Mesoporous Carbon as a Bifunctional Host for High‐Performance Thick Cathodes for Lithium‐Sulfur Batteries

Lithium‐sulfur (Li‐S) batteries are highly considered as a next‐generation energy storage device due to their high theoretical energy density. For practical viability, reasonable active‐material loading of >4.0 mg cm^?2 must be employed, at a cost to the intrinsic instability of sulfur cathodes. The incursion of lithium polysulfides (LiPS) at higher sulfur loadings results in low active material utilization and poor cell cycling capability. The use of high‐surface‐area hierarchical macro/mesoporous inverse opal (IOP) carbons to investigate the effects of pore volume and surface area on the electrochemical stability of high‐loading, high‐thickness cathodes for Li‐S batteries is presented here. The IOP carbons are additionally doped with pyrrolic‐type nitrogen groups (N‐IOP) to act as a polar polysulfide mediator and enhance the active‐material reutilization. With a high sulfur loading of 6.0 mg cm^?2, the Li‐S cells assembled with IOP and N‐IOP carbons are able to attain a high specific capacity of, respectively, 1242 and 1162 mA h g^?1. The N‐IOP enables the Li‐S cells to demonstrate good electrochemical performance over 300 cycles.     

Promoting the Transformation of Li2S2 to Li2S: Significantly Increasing Utilization of Active Materials for High‐Sulfur‐Loading Li–S Batteries

Lithium–sulfur (Li–S) batteries with high sulfur loading are urgently required in order to take advantage of their high theoretical energy density. Ether‐based Li–S batteries involve sophisticated multistep solid–liquid–solid–solid electrochemical reaction mechanisms. Recently, studies on Li–S batteries have widely focused on the initial solid (sulfur)–liquid (soluble polysulfide)–solid (Li₂S₂) conversion reactions, which contribute to the first 50% of the theoretical capacity of the Li–S batteries. Nonetheless, the sluggish kinetics of the solid–solid conversion from solid‐state intermediate product Li₂S₂ to the final discharge product Li₂S (corresponding to the last 50% of the theoretical capacity) leads to the premature end of discharge, resulting in low discharge capacity output and low sulfur utilization. To tackle the aforementioned issue, a catalyst of amorphous cobalt sulfide (CoS₃) is proposed to decrease the dissociation energy of Li₂S₂ and propel the electrochemical transformation of Li₂S₂ to Li₂S. The CoS₃ catalyst plays a critical role in improving the sulfur utilization, especially in high‐loading sulfur cathodes (3–10 mg cm^?2). Accordingly, the Li₂S/Li₂S₂ ratio in the discharge products increased to 5.60/1 from 1/1.63 with CoS₃ catalyst, resulting in a sulfur utilization increase of 20% (335 mAh g^?1) compared to the counterpart sulfur electrode without CoS₃.     

Defect-Rich Single Atom Catalyst Enhanced Polysulfide Conversion Kinetics to Upgrade Performance of Li–S Batteries

Lithium–sulfur (Li–S) batteries have attracted considerable attention owing to their extremely high energy densities. However, the application of Li–S batteries has been limited by low sulfur utilization, poor cycle stability, and low rate capability. Accelerating the rapid transformation of polysulfides is an effective approach for addressing these obstacles. In this study, a defect-rich single-atom catalytic material (Fe-N4/DCS) is designed. The abundantly defective environment is favorable for the uniform dispersion and stable existence of single-atom Fe, which not only improves the utilization of single-atom Fe but also efficiently adsorbs polysulfides and catalyzes the rapid transformation of polysulfides. To fully exploit the catalytic activity, catalytic materials are used to modify the routine separator (Fe-N₄/DCS/PP). Density functional theory and in situ Raman spectroscopy are used to demonstrate that Fe-N₄/DCS can effectively inhibit the shuttling of polysulfides and accelerate the redox reaction. Consequently, the Li–S battery with the modified separator achieves an ultralong cycle life (a capacity decay rate of only 0.03% per cycle at a current of 2 C after 800 cycles), and an excellent rate capability (894 mAh g⁻¹ at 3 C). Even at a high sulfur loading of 5.51 mg cm⁻² at 0.2 C, the reversible areal capacity still reaches 5.4 mAh cm⁻².     

Highly Safe Electrolyte Enabled via Controllable Polysulfide Release and Efficient Conversion for Advanced Lithium–Sulfur Batteries

Conventional lithium–sulfur batteries often suffer from fatal problems such as high flammability, polysulfide shuttling, and lithium dendrites growth. Here, highly‐safe lithium–sulfur batteries based on flame‐retardant electrolyte (dimethoxyether/1,1,2,2‐tetrafluoroethyl 2,2,3,3‐tetrafluoropropyl ether) coupled with functional separator (nanoconductive carbon‐coated cellulose nonwoven) to resolve aforementioned bottle‐neck issues are demonstrated. It is found that this flame‐retardant electrolyte exhibits excellent flame retardancy and low solubility of polysulfide. In addition, Li/Li symmetrical cells using such flame‐retardant electrolyte deliver extraordinary long‐term cycling stability (less than 10 mV overpotential) for over 2500 h at 1.0 mA cm^?2 and 1.0 mAh cm^?2. Moreover, bare sulfur cathode–based lithium–sulfur batteries using this flame retardant electrolyte coupled with nanoconductive carbon‐coated cellulose separator can retain 83.6% discharge capacity after 200 cycles at 0.5 C. Under high charge/discharge rate (4 C), lithium–sulfur cells still show high charge/discharge capacity of ≈350 mAh g^?1. Even at an elevated temperature of 60 °C, discharge capacity of 870 mAh g^?1 can be retained. More importantly, high‐loading bare sulfur cathode (4 mg cm^?2)–based lithium–sulfur batteries can also deliver high charge/discharge capacity over 806 mAh g^?1 after 56 cycles. Undoubtedly, the strategy of flame retardant electrolyte coupled with carbon‐coated separator enlightens highly safe lithium–sulfur batteries at a wide range of temperature.     

Atomic Interlamellar Ion Path in High Sulfur Content Lithium‐Montmorillonite Host Enables High‐Rate and Stable Lithium–Sulfur Battery

Fast lithium ion transport with a high current density is critical for thick sulfur cathodes, stemming mainly from the difficulties in creating effective lithium ion pathways in high sulfur content electrodes. To develop a high‐rate cathode for lithium–sulfur (Li–S) batteries, extenuation of the lithium ion diffusion barrier in thick electrodes is potentially straightforward. Here, a phyllosilicate material with a large interlamellar distance is demonstrated in high‐rate cathodes as high sulfur loading. The interlayer space (≈1.396 nm) incorporated into a low lithium ion diffusion barrier (0.155 eV) significantly facilitates lithium ion diffusion within the entire sulfur cathode, and gives rise to remarkable nearly sulfur loading‐independent cell performances. When combined with 80% sulfur contents, the electrodes achieve a high capacity of 865 mAh g^?1 at 1 mA cm^?2 and a retention of 345 mAh g^?1 at a high discharging/charging rate of 15 mA cm^?2, with a sulfur loading up to 4 mg. This strategy represents a major advance in high‐rate Li–S batteries via the construction of fast ions transfer paths toward real‐life applications, and contributes to the research community for the fundamental mechanism study of loading‐independent electrode systems.     

Long‐Life Lithium–Sulfur Batteries with a Bifunctional Cathode Substrate Configured with Boron Carbide Nanowires

Developing high‐energy‐density lithium–sulfur (Li–S) batteries relies on the design of electrode substrates that can host a high sulfur loading and still attain high electrochemical utilization. Herein, a new bifunctional cathode substrate configured with boron‐carbide nanowires in situ grown on carbon nanofibers (B₄C@CNF) is established through a facile catalyst‐assisted process. The B₄C nanowires acting as chemical‐anchoring centers provide strong polysulfide adsorptivity, as validated by experimental data and first‐principle calculations. Meanwhile, the catalytic effect of B₄C also accelerates the redox kinetics of polysulfide conversion, contributing to enhanced rate capability. As a result, a remarkable capacity retention of 80% after 500 cycles as well as stable cyclability at 4C rate is accomplished with the cells employing B₄C@CNF as a cathode substrate for sulfur. Moreover, the B₄C@CNF substrate enables the cathode to achieve both high sulfur content (70 wt%) and sulfur loading (10.3 mg cm^?2), delivering a superb areal capacity of 9 mAh cm^?2. Additionally, Li–S pouch cells fabricated with the B₄C@CNF substrate are able to host a high sulfur mass of 200 mg per cathode and deliver a high discharge capacity of 125 mAh after 50 cycles.     

A Quinonoid‐Imine‐Enriched Nanostructured Polymer Mediator for Lithium–Sulfur Batteries

The reversible formation of chemical bonds has potential for tuning multi‐electron redox reactions in emerging energy‐storage applications, such as lithium?sulfur batteries. The dissolution of polysulfide intermediates, however, results in severe shuttle effect and sluggish electrochemical kinetics. In this study, quinonoid imine is proposed to anchor polysulfides and to facilitate the formation of Li₂S₂/Li₂S through the reversible chemical transition between protonated state (? NH⁺ ?) and deprotonated state (? N?). When serving as the sulfur host, the quinonoid imine‐doped graphene affords a very tiny shuttle current of 2.60 × 10^?4 mA cm^?2, a rapid redox reaction of polysulfide, and therefore improved sulfur utilization and enhanced rate performance. A high areal specific capacity of 3.72 mAh cm^?2 is achieved at 5.50 mA cm^?2 on the quinonoid imine‐doped graphene based electrode with a high sulfur loading of 3.3 mg cm^?2. This strategy sheds a new light on the organic redox mediators for reversible modulation of electrochemical reactions.     

High‐Performance Li–SeSx All‐Solid‐State Lithium Batteries

All‐solid‐state Li–S batteries are promising candidates for next‐generation energy‐storage systems considering their high energy density and high safety. However, their development is hindered by the sluggish electrochemical kinetics and low S utilization due to high interfacial resistance and the electronic insulating nature of S. Herein, Se is introduced into S cathodes by forming SeS_x solid solutions to modify the electronic and ionic conductivities and ultimately enhance cathode utilization in all‐solid‐state lithium batteries (ASSLBs). Theoretical calculations confirm the redistribution of electron densities after introducing Se. The interfacial ionic conductivities of all achieved SeS_x–Li₃PS₄ (x = 3, 2, 1, and 0.33) composites are 10^?6 S cm^?1. Stable and highly reversible SeS_x cathodes for sulfide‐based ASSLBs can be developed. Surprisingly, the SeS₂/Li₁₀GeP₂S₁₂–Li₃PS₄/Li solid‐state cells exhibit excellent performance and deliver a high capacity over 1100 mAh g^?1 (98.5% of its theoretical capacity) at 50 mA g^?1 and remained highly stable for 100 cycles. Moreover, high loading cells can achieve high areal capacities up to 12.6 mAh cm^?2. This research deepens the understanding of Se–S solid solution chemistry in ASSLB systems and offers a new strategy to achieve high‐performance S‐based cathodes for application in ASSLBs.     

A Dual-Functional Conductive Framework Embedded with TiN-VN Heterostructures for Highly Efficient Polysulfide and Lithium Regulation toward Stable Li–S Full Batteries

Lithium–sulfur (Li–S) batteries are strongly considered as next-generation energy storage systems because of their high energy density. However, the shuttling of lithium polysulfides (LiPS), sluggish reaction kinetics, and uncontrollable Li-dendrite growth severely degrade the electrochemical performance of Li–S batteries. Herein, a dual-functional flexible free-standing carbon nanofiber conductive framework in situ embedded with TiN-VN heterostructures (TiN-VN@CNFs) as an advanced host simultaneously for both the sulfur cathode (S/TiN-VN@CNFs) and the lithium anode (Li/TiN-VN@CNFs) is designed. As cathode host, the TiN-VN@CNFs can offer synergistic function of physical confinement, chemical anchoring, and superb electrocatalysis of LiPS redox reactions. Meanwhile, the well-designed host with excellent lithiophilic feature can realize homogeneous lithium deposition for suppressing dendrite growth. Combined with these merits, the full battery (denoted as S/TiN-VN@CNFs || Li/TiN-VN@CNFs) exhibits remarkable electrochemical properties including high reversible capacity of 1110 mAh g⁻¹ after 100 cycles at 0.2 C and ultralong cycle life over 600 cycles at 2 C. Even with a high sulfur loading of 5.6 mg cm⁻², the full cell can achieve a high areal capacity of 5.5 mAh cm⁻² at 0.1 C. This work paves a new design from theoretical and experimental aspects for fabricating high-energy-density flexible Li–S full batteries.