Advanced Lithium Sulfur Batteries Research Articles

Achieving High-Performance Lithium-Sulfur Batteries by Modulating Li+ Desolvation Barrier with Liquid Crystal Polymers.

Lithium-sulfur (Li-S) batteries offer high theoretical capacity but are hindered by poor rate capability and cycling stability due to sluggish Li2S precipitation kinetics. Here a sulfonate-group-rich liquid crystal polymer (poly-2,2'-disulfonyl-4,4'-benzidine terephthalamide, PBDT) is designed and fabricated to accelerate Li2S precipitation by promoting the desolvation of Li+ from electrolyte. PBDT-modified separators are employed to assemble Li-S batteries, which deliver a remarkable rate capacity (761 mAh g-1 at 4 C) and cycling stability (500 cycles with an average decay rate of 0.088% per cycle at 0.5 C). A PBDT-based pouch cell even delivers an exceptional capacity of ≈1400 mAh g-1 and an areal capacity of ≈11 mAh cm-2 under lean-electrolyte and high-sulfur-loading condition, demonstrating promise for practical applications. Results of Raman spectra, molecular dynamic (MD) and density functional theory (DFT) calculations reveal that the abundant anionic sulfonate groups of PBDT aid in Li+ desolvation by attenuating Li+-solvent interactions and lowering the desolvation energy barrier. Plus, the polysulfide adsorption/catalysis is also excluded via electrostatic repulsion. This work elucidates the critical impact of Li+ desolvation on Li-S batteries and provides a new design direction for advanced Li-S batteries.

All-purpose redox-active metal-organic frameworks as both cathodic and anodic host materials for advanced lithium-sulfur batteries

All-purpose redox-active metal-organic frameworks as both cathodic and anodic host materials for advanced lithium-sulfur batteries

Mxene quantum dots decorated reduced graphene oxide networks as multifunctional electrocatalyst for advanced lithium–sulfur batteries

Lithium sulfur (Li-S) battery has shown great potential as an attractive rechargeable energy storage devices, but the shuttle behavior and slow conversion kinetics of the intermediate lithium polysulfides (LiPSs) are the main obstacles to the practical application of Li-S battery. Herein, a simple and scalable spray drying strategy was used to construct conductive polar Ti3C2 MXene quantum dots (QDs)-decorated reduced graphene oxide (rGO) microsphere (rGO@Ti3C2 QDs) as efficient electrocatalyst and absorbent for Li-S battery. Firstly, the DFT results show that Ti3C2 QDs can effectively adsorb and catalyze LiPSs conversion. This ability can be attributed to the Ti3C2 QDs can provide a large number of LiPSs catalytic active sites. In addition, the rGO provides physical LiPSs constraint and a flexible substrate to prevent QDs from aggregating. Moreover, both parts are conductive, effectively improving the electron/charge transfer. Therefore, this unique structure and composition show high LiPSs adsorption and catalysis, while allowing rapid Li+/electron transfer. As a result, the S/rGO@Ti3C2 QDs electrode provides high initial capacity (1185 mAh/g at 0.2C), good rate capability (758 mAh/g at 3C), and excellent long-term cyclability (500 cycles at 1C with low attenuation of 0.07% per cycle), as well as an excellent electrochemical performance even at high sulfur loading. Meanwhile, the Li-S pouch cell based on S/rGO@Ti3C2 QDs also achieved a high initial energy density of 230.9 Wh kg−1. This work may provide a promising strategy to obtain better electrochemical performance by introducing quantum dots into Li-S cathodes.

Boron doped MXenes as redox catalyst for highly efficient and reversible polysulfide conversion

Due to the accumulation of soluble polysulfides during the process reaction process, the shuttle effect emerges and significantly impacts the electrochemical performance. The development of novel efficient catalysts and adsorbents is a very popular way to fabricate the sulfur host materials. MXene as one of the most novel and popular materials have been wildly used in electrochemical energy storage. While the limited catalytic activity and adsorption capacity hindering its application in lithium sulfur batteries. Here, we introduced boron atoms as dopants in a creative modification of MXene (B-MXene). The introduced B atoms can effectively mitigate the “shuttle effect” through chemical adsorption, owing to their electron-deficient nature. Furthermore, the introduction of boron atoms and vacancy can modify the electronic structure, enhancing the catalytic activity of MXene by providing empty perpendicular-orientation orbitals. As a result, B-MXene exhibited excellent electrochemical performance, maintaining at 943 mA h g−1 at a current density of 1.0C, after 500cycles, with a corresponding decay rate as low as 0.046 %. This work proposes an efficient strategy to fabricate highly efficient electrocatalysts for advanced lithium-sulfur batteries (Li-S batteries).

Dual-ultrasmall Sb and Sb6O13 nanodots co-anchored MXene with manipulable structural chemistry modulating bidirectional kinetics toward advanced lithium-sulfur batteries

Exfoliation and modulation of intercalated layered transition metal carbides and/or nitrides (MAX) into their derivatives (MXenes) featured with manipulable structural chemistry by remain enormous challenges toward practical applications. Herein, an extraordinary low-dimensional MXenes modulated by dual-ultrasmall Sb and Sb6O13 nanodots via in situ structural editing protocol using Lewis-basic fluorides in organic molten salts. Their original internal non-van der Waals bonds and physicochemical natures are simultaneously mediated by manipulating fluorine anions and antimony cations as chemical scissors generating into zero- and one-dimensional MXenes (MFNCTS-Z, MFNCTS-O) encapsulated by hierarchical porous N-doped carbon. Experimental and theoretical results manifest MFNCTSs as alternative dual-functional hosts toward both sulfur (S) cathode and lithium (Li) anode modulating bidirectional kinetics originated from their synergistic effect of physical confinement and chemical anchor effect accelerating polysulfides redox chemistry, and homogeneous lithium deposition. As a result, the assembled lithium-sulfur full batteries offer impressive electrochemical performances. This work paves a new avenue for developing low-dimensional MXenes by controllable structural editing strategy toward practical energy conversion and storage fields.

Heteroatom doping carbon film derived from hyphae as a self-supporting cathode for advanced lithium sulfur batteries

Much attention has been paid to lithium sulfur battery due to its high energy density. However, low S loading and poor cycling stability have hindered their commercialization. In this work, a porous carbon film with rich heteroatom doping was prepared from the Penicillium chrysogenum hyphae film by freezing drying and high-temperature carbonization. Then the carbon film loaded polysulfide solution was utilized as a self-supporting cathode for Li-S batteries. The self-supporting cathode exhibited good rate performance (513.1 mAh/g at 1C) and improved cycling stability (more than 400 cycles) under a high current density (0.5C). This is mainly attributed to the abundant heteroatoms that provided active sites with superior adsorption ability for lithium polysulfide, which not only enhanced the cycling stability but also facilitated the conversion kinetics. Besides, the fibrous network morphology with affluent porous structures inherited from hyphae provided a large specific surface area and sufficient space for accommodating active substances. This work shows the great potential of hyphae derived porous carbon electrodes for high-performance energy storage applications.

Advanced Lithium-sulfur batteries enabled by a flexible electrocatalytic membrane of TiO2 and SiO2 co-decorated necklace-like carbon nanofibers

Lithium-sulfur (Li-S) batteries are regarded as new energy storage systems due to their low cost and high specific energy density; however, their commercial prospects are hindered by the shuttle effect of lithium polysulfides (LiPSs). Herein, the fabricating necklace-like carbon nanofibers membrane co-decorated by TiO2 and SiO2 (TiO2@SiO2/CNF) is prepared by the electrospinning technique as an interlayer to catalyze the conversion of LiPSs in Li-S batteries. The necklace-like nanofibers provide a three-dimensional conductive network, enabling SiO2 synergy with TiO2 to accelerate the redox kinetics of LiPSs through an enhanced interfacial effect. The Li-S batteries based on TiO2@SiO2/CNF interlayers exhibit an impressive specific capacity of 658 mAh g−1 at 3.0C, and their performances are decayed only 0.05 % per cycle at 1.0C within 500cycles. Our study reveals that the shuttle effect addition of LiPSs can be significantly improved by rational structural design, thus enhancing the electrochemical performance of Li-S batteries. The synthesis of necklace-like TiO2@SiO2/CNF presents a promising strategy for designing functional interlayers for advanced Li-S batteries.

Synergistically accelerating capture and catalytic conversion of polysulfides by Co@NCNT-MoSe2 nanocomposite modified separator for advanced Lithium-Sulfur batteries

Lithium-sulfur (Li-S) battery with a high theoretical energy density (2600 Wh·kg−1) is considered as a promising energy storage system. However, the shuttle effect and the sluggish redox kinetics of lithium polysulfides (LiPSs) lead to low sulfur utilization. A multifunctional layer modified on separator, as a collaborator of capturer-catalyst-conductor, is be regarded as an effective strategy to solve these problems. Herein, the Co@NCNT-MoSe2 nanocomposite as a modified layer is synthesized with a mesoporous structure by the hydrothermal reaction, in which a large number of transparent MoSe2 nanosheets grow outside NCNT embedded with Co nanoparticles, forming a flower-like outer walls of tube. The modified layer displays the significant features of capturing and catalytic conversion toward LiPSs, attributing to strong adsorption abilities, abundant catalytic active sites, and efficient transferring pathway of electron/Li+. Benefitting from these alluring properties, the results demonstrate that the modified separator offers a high discharge capacity of 983.2 mAh·g−1 at 0.2C after 200 cycles. Even at 2C, after long-term 1000 cycles, it still shows a superb capacity of 725 mAh·g−1 accompanied by a low capacity fading of 0.042 % per cycle. More notably, at 0.2C, the modified separator can realize an ideal areal capacity of 5.24 mAh·cm−2 under high S load (5 mg·cm−2) and poor electrolyte (7.5 μL·mg−1). Therefore, this work will provide a new insight on the development of multifunctional separators to achieve a long-life battery with high sulfur utilization by restraining shuttle effect and accelerate redox kinetics of LiPSs.

Organic Electrolyte Additive: Dual Functions Toward Fast Sulfur Conversion and Stable Li Deposition for Advanced Li-S Batteries.

Lithium-sulfur (Li-S) battery is of great potential for the next generation energy storage device due to the high specific capacity energy density. However, the sluggish kinetics of S redox and the dendrite Li growth are the main challenges to hinder its commercial application. Herein, an organic electrolyte additive, i.e., benzyl chloride (BzCl), is applied as the remedy to address the two issues. In detail, BzCl can split into Bz· radical to react with the polysulfides, forming a Bz-S-Bz intermediate, which changes the conversion path of S and improves the kinetics by accelerating the S splitting. Meanwhile, a tight and robust solid electrolyte interphase (SEI) rich in inorganic ingredients namely LiCl, LiF, and Li2 O, is formed on the surface of Li metal, accelerating the ion conductivity and blocking the decomposition of the solvent and lithium polysulfides. Therefore, the Li-S battery with BzCl as the additive remains high capacity of 693.2mAhg-1 after 220 cycles at 0.5C with a low decay rate of 0.11%. This work provides a novel strategy to boost the electrochemical performances in both cathode and anode and gives a guide on the electrolyte design toward high-performance Li-S batteries.

Spatial configuration of interlayer maximizing suppression and conversion efficiency of lithium polysulfides for advanced lithium–sulfur batteries

Shuttle effect of polysulfides and sluggish redox kinetics of sulfur are two tricky problems in lithium–sulfur (Li–S) batteries. Engineering interlayer between sulfur cathode and separator is an innovative approach to alleviate these weaknesses. From the spatial perspective, we validate an efficient interlayer by regulating the stacking configuration composed of a conductive layer (carbonized polyacrylonitrile-carbon nanotube, CPCNT) and catalytic layer (carbonized polyacrylonitrile-selenium, CPSe), forming a hierarchical polysulfide suppression and conversion system. Electrochemical measurements reveal that the contact priority of CPCNT or CPSe on sulfur cathode poses a momentous impact on the overall working efficiency of interlayer. Accordingly, CPSe@CPCNT|S enables Li–S batteries to deliver a specific capacity of up to 760 mAh/g at 1.0C after 500 cycles. Impressively, Li–S batteries endure 250 cycles with 87% capacity retention at 0.2C, even under a sulfur loading of 6.1 mg/cm2. The polysulfide diffusion visualization coupled with finite elemental analyses disclose that CPSe@CPCNT|S configuration shapes a higher diffusion damping towards polysulfides, while maintaining a smooth electron motion pathway from cathode to interlayer for polysulfide conversion, which is the decisive cause of the enhanced electrochemical performance. This research affords a spatial strategy for interlayer design in Li–S batteries and other alkali metal-sulfur batteries.

Preparation of polyaniline-coated cobalt nitride nanoflowers as sulfur host for advanced lithium–sulfur battery

Lithium–sulfur (Li–S) batteries are promising candidates for large-scale high-energy-density devices owing to their potential high energy density, low cost, and more pronounced ecological compatibility. Nevertheless, their commercial applications of Li–S batteries are limited by the low electrical conductivity of sulfur, huge volume swell, shuttle effect, and slow redox reactions. In order to solve the above issues, various sulfur hosts have been developed and combined with active sulfur to form a composite. Polyaniline-coated cobalt nitride nanoflowers loaded with sulfur (CoN/S@PANI nanoflowers) were prepared by simple liquid phase precipitation followed by nitridation, sulfurization, and coating with polypyrrole. The CoN nanoflowers possessed a hierarchical nanostructure with a large specific surface area, which could reduce the volume swelling of sulfur and the shuttle effect of polysulfides. The polyaniline coating with high electrical conductivity can adsorb the polysulfides and promote the electrochemical reaction kinetics. Therefore, the CoN/S@PANI nanoflowers exhibit a high initial capacity of 895 mAh g−1 at 0.5 A g−1, which was kept at 736 mAh g−1 over 100 cycles. This paper reports a new route to prepare a sulfur host for advanced lithium–sulfur batteries.

Hybrid Ascharite/Reduced Graphene Oxide with Polysulfide Adsorption Host for Advanced Lithium-Sulfur Batteries.

Balancing the adsorption of lithium-polysulfide intermediates on polar host material surfaces and the effect of their electronic conductivity in the subsequent oxidation and reduction kinetics of electrochemical reactions is necessary and remains a challenge. Herein, we have evaluated the role of polarity and conductivity in preparing a series of ascharite/reduced graphene oxide (RGO) aerogels by dispersing strong polar ascharite nanowires of varying mass into the conductive RGO matrix. When severed as Li-S battery cathodes, the optimized S@ascharite/RGO cathode with a sulfur content of 73.8 wt % demonstrates excellent rate performance and cycle stability accompanied by a high-capacity retention for 500 cycles at 1.0 C. Interesting advantages including the enhanced adsorption ability by the formation of the Mg-S and Li bonds, the continuous and quick electron/ion transportations assembled conductive RGO framework, and the effective deposition of Li2S are combined in the ascharite/RGO aerogel hosts. The electrochemical results further demonstrate that the polarity of ascharite components for the S cathode plays a dominant role in the improvement of electrochemical performance, but the absence of a conductive substrate leads to serious capacity attenuation, especially the rate performance. The balanced design protocol provides a universal method for the synthesis of multiple S hosts for high-performance LSBs.

A biomass-rich, self-healable, and high-adhesive polymer binder for advanced lithium-sulfur batteries

Although lithium-sulfur (Li-S) batteries have attracted a great deal of attention due to their ultrahigh energy density, the significant dissolution and shuttle of polysulfides, coupled with the unstable electrode structure, result in a substantial decline in capacity, thereby hindering their practical application in rapidly advancing energy storage systems. In this work, we prepare an environmentally friendly binder (LA-GA) that possesses self-healing abilities and high adhesion by combining dynamic disulfide (SS) bonds with abundant polar functional groups. Significantly, the self-healing capability provided by SS bonds facilitates the repair of cracks resulting from cathode volume expansion. Simultaneously, the polar functional groups (carboxyl and pyrogallol) not only enhance adhesion, preserving cathode integrity, but also effectively participate in lithium polysulfide adsorption, thereby inhibiting the shuttle effect. As a result, sulfur cathodes incorporating the LA-GA binder demonstrate favorable cycling stability, with a high capacity retention of 81.9 % when tested at 0.2C for 100 cycles. Additionally, the long-term cycling performance is satisfactory, showing a small capacity decline rate of 0.0469 % per cycle over 700 cycles at 1.0C.

Separator Modified by Carbon-Encapsulated CoFe Alloy Nanoparticles Supported on Carbon Nanotubes for Advanced Lithium–Sulfur Batteries

Separator Modified by Carbon-Encapsulated CoFe Alloy Nanoparticles Supported on Carbon Nanotubes for Advanced Lithium–Sulfur Batteries

Sulfurized polyacrylonitrile as cathodes for advanced lithium-sulfur batteries: advances in modification strategies.

Sulfurized polyacrylonitrile (S@PAN) composites have gathered a lot of interest because of their advantages of high theoretical energy density, excellent cycling stability, and environmental friendliness. Meanwhile, their unique "covalent bonding" mechanism effectively avoids the dissolution and shuttling of polysulfides, and thus they are expected to be the most promising candidate for the cathode material in lithium-sulfur (Li-S) batteries. Over the past five years, S@PAN cathode materials have been widely studied in Li-S batteries, and it is very important to summarize the advances over time for their practical applications. This article reviews the latest progress concerning the modification of S@PAN cathode materials for improving poor electrical conductivity, low sulfur content, and sluggish reaction kinetics, and proposes possible research directions. We hope this review provides valuable insights and references for future research on Li-S batteries.

Synergistic design of a semi-hollow core-shell structure and a metal-organic framework-derived Co/Zn selenide coated with MXene for high-performance lithium-sulfur batteries.

Lithium-sulfur batteries have garnered significant interest as potential energy storage systems for the future, owing to their remarkable theoretical specific capacity (1675 mA h g-1) and energy density (2600 W h kg-1). However, their development has been severely impeded by several challenges, including the low intrinsic conductivity of sulfur, volume expansion issues, and the polysulfide shuttle effect. To address these issues, polar metal compounds with nanostructures featuring hollow shells and catalytic functions have emerged as promising materials for designing advanced lithium-sulfur batteries. In this study, bimetallic selenides with varying degrees of hollowness are synthesized using a tannic acid etching and selenization strategy. By comparing the electrochemical characteristics of composite electrodes with different degrees of hollowness, an optimal semi-hollow core-shell structure is identified, implying that reasonable structural designing of metal compounds carries immense importance in improving electrochemical reactions. Moreover, the appropriate degree of hollowness effectively mitigates volume expansion issues associated with the sulfur cathode. Consequently, bimetallic selenides with a hollow core-shell structure coated with conductive MXene material exhibit superior electrochemical performance. The synergistic effect achieved through the judicious design of the hollow core-shell structure and the utilization of polar metal compounds has proved instrumental in enhancing the redox kinetics of lithium-sulfur batteries. As such, this research presents a novel avenue for the development of high-performance lithium-sulfur batteries.

Co/Mon Invigorated Bilateral Kinetics Modulation for Advanced Lithium-Sulfur Batteries.

Sluggish sulfur redox kinetics and Li-dendrite growth are the main bottlenecks for lithium-sulfur (Li-S) batteries. Separator modification serves as a dual-purpose approach to address both of these challenges. In this study, the Co/MoN composite is rationally designed and applied as the modifier to modulate the electrochemical kinetics on both sides of the sulfur cathode and lithium anode. Benefiting from its adsorption-catalysis function, the decorated separators (Co/MoN@PP) not only effectively inhibit polysulfides (LiPSs) shuttle and accelerate their electrochemical conversion but also boost Li+ flux, realizing uniform Li plating/stripping. The accelerated LiPSs conversion kinetics and excellent sulfur redox reversibility triggered by Co/MoN modified separators are evidenced by performance, in-situ Raman detection and theoretical calculations. The batteries with Co/MoN@PP achieve a high initial discharge capacity of 1570 mAh g-1 at 0.2 C with a low decay rate of 0.39%, uniform Li+ transportation at 1mA cm-2 over 800h. Moreover, the areal capacity of 4.62 mAh cm-2 is achieved under high mass loadings of 4.92mg cm-2. This study provides a feasible strategy for the rational utilization of the synergistic effect of composite with multifunctional microdomains to solve the problems of Li anode and S cathode toward long-cycling Li-S batteries.

Li2S@C/CNT composite cathode with botryoidal conductive network for advanced lithium–sulfur batteries

Li2S@C/CNT composite cathode with botryoidal conductive network for advanced lithium–sulfur batteries

Covalently introducing sulfur in a thiol-rich MOF toward advanced lithium-sulfur batteries

The shuttle effect and sluggish reaction kinetics have hindered the practical application of lithium-sulfur (Li-S) batteries. In this work, a thiol-rich MOF was in situ synthesized on carbon nanotube (CNT) and sulfur was covalently connected to this composite to form a MOF-sulfur copolymer (S-UiO-66(SH)2@CNT). Benefiting from the strong covalent interaction between thiol groups and sulfur, the resultant cathode can retard the shuttle effect and simultaneously strengthen the redox kinetics. As a result, the S-UiO-66(SH)2@CNT cathode exhibits a higher capacity retention of 93.27 % at 0.5C during 200 cycles than that of the physically mixed S/UiO-66@CNT cathode (64.94 %). This work will provide insight into the design of advanced MOF-based cathodes for Li-S batteries.

Enhancing the cycling stability of Li-S batteries with flexible freestanding sulfur cathodes through a spider-hunting strategy

Flexible, high-capacity, and long-lasting freestanding sulfur cathodes are essential for developing advanced lithium-sulfur (Li-S) batteries in next-generation flexible electronic devices. However, the severe shuttle effect of lithium polysulfides (LiPSs) hinders their potential applications. This work introduces a flexible freestanding MX-CPNTs-CNTs@NS cathode for Li-S batteries by utilizing a spider-hunting strategy. In this strategy, carbonized polypyrrole nanotubes (CPNTs) and carbon nanotubes (CNTs) intertwine to form a 3D flexible and conductive spiderweb-like skeleton. The incorporation of MXene nanosheets as a function of spiders enables the regulation of a rich hierarchical porous structure. Additionally, the polar terminal functional groups of MXene nanosheets and the pyridinic N of CPNTs contribute to the chemical adsorption and electrocatalysis of LiPSs. The synergistic effect of physical and chemical inhibition strategies results in stable electrochemical performance, including a high specific capacity of 1203.2 mAh/g at 0.1C, and extended cycling stability of 739.6 mAh/g at 1C after 500 cycles (low decay rate of 0.036%). The excellent flexibility, specific capacity, and cycling stability make the freestanding MX-CPNTs-CNTs@NS cathode promising for high-performance flexible electronic devices.