Application Of Lithium-sulfur Batteries Research Articles

Surface design for high ion flux separator in lithium-sulfur batteries

Addressing the shuttle effect is a critical challenge in realizing practical applications of lithium-sulfur batteries. One promising avenue refers to the surface modification of separators, transitioning them from closed to open structures. In the current investigation, a high ion flux separator was devised by means of MnO2 self-assembly onto a Porous Polypropylene (PP) separator, subsequently coupling it with biochar. The separator exhibited favorable ion and electronic conductivity. Moreover, it adeptly captured and transformed polysulfides into Li2S2/Li2S, cyclically curbing the mobility of Polysulfide lithium (LiPSs). In addition, this augmentation in the kinetic conversion of LiPSs during the electrochemical process translated into an impressive discharge specific capacity and area capacity of 939 mAh/g and 4 mAh cm−2, respectively. Moreover, this innovative design methodology provides an alternative avenue for future separator designs within lithium-sulfur batteries.

Reinforced Lewis covalent bond by twinborn nitride heterostructure for lithium-sulfur batteries

The practical application of lithium-sulfur (Li-S) batteries, as promising next-generation batteries, is hindered by their shuttle effect and the slow redox kinetics. Herein, a tungsten and molybdenum nitride heterostructure functionalized with hollow metal-organic framework-derived carbon (W2N/Mo2N) was proposed as the sulfur host. The hollow spherical structure provides storage space for sulfur, enhances electrical conductivity, and inhibits volume expansion. The metal atoms in the nitrides bonded with lithium polysulfides (LiPSs) through Lewis covalent bonds, enhancing the high catalytic activity of the nitrides and effectively reducing the energy barrier of LiPSs redox conversion. Moreover, the high intrinsic conductivity of nitrides and the ability of the heterostructure interface to accelerate electron/ion transport improved the Li+ transmission. By leveraging the combined properties of strong adsorption and high catalytic activity, the sulfur host effectively inhibited the shuttle effect and accelerated the redox kinetics of LiPSs. High-efficiency Li+ transmission, strong adsorption, and the efficient catalytic conversion activities of LiPSs in the heterostructure were experimentally and theoretically verified. The results indicate that the W2N/Mo2N cathode provides stable, and long-term cycling (over 2000 cycles) at 3 C with a low attenuation rate of 0.0196% per cycle. The design strategy of a twinborn nitride heterostructure thus provides a functionalized solution for advanced Li-S batteries.

NbN quantum dots anchored hollow carbon nanorods as efficient polysulfide immobilizer and lithium stabilizer for Li-S full batteries

The shuttle effect of lithium polysulfides (LiPSs) and uncontrollable lithium dendrite growth seriously hinder the practical application of lithium-sulfur (Li-S) batteries. To simultaneously address such issues, monodispersed NbN quantum dots anchored on nitrogen-doped hollow carbon nanorods (NbN@NHCR) are elaborately developed as efficient LiPSs immobilizer and Li stabilizer for high-performance Li-S full batteries. Density functional theory (DFT) calculations and experimental characterizations demonstrate that the sulfiphilic and lithiophilic NbN@NHCR hybrid can not only efficiently immobilize the soluble LiPSs and facilitate diffusion-conversion kinetics for alleviating the shuttling effect, but also homogenize the distribution of Li+ ions and regulate uniform Li deposition for suppressing Li-dendrite growth. As a result, the assembled Li-S full batteries (NbN@NHCR-S||NbN@NHCR-Li) deliver excellent long-term cycling stability with a low decay rate of 0.031% per cycle over 1000 cycles at high rate of 2 C. Even at a high S loading of 5.8 mg cm−2 and a low electrolyte/sulfur ratio of 5.2 µL mg−1, a large areal capacity of 6.2 mA h cm−2 can be achieved in Li-S pouch cell at 0.1 C. This study provides a new perspective via designing a dual-functional sulfiphilic and lithiophilic hybrid to address serious issues of the shuttle effect of S cathode and dendrite growth of Li anode.

Breaking the Barrier: Strategies for Mitigating Shuttle Effect in Lithium-Sulfur Batteries Using Advanced Separators.

Lithium-sulfur (Li-S) batteries are considered one of the most promising energy storage systems due to their high theoretical capacity, high theoretical capacity density, and low cost. However, challenges such as poor conductivity of sulfur (S) elements in active materials, the "shuttle effect" caused by lithium polysulfide, and the growth of lithium dendrites impede the commercial development of Li-S batteries. As a crucial component of the battery, the separator plays a vital role in mitigating the shuttle effect caused by polysulfide. Traditional polypropylene, polyethylene, and polyimide separators are constrained by their inherent limitations, rendering them unsuitable for direct application in lithium-sulfur batteries. Therefore, there is an urgent need for the development of novel separators. This review summarizes the applications of different separator preparation methods and separator modification methods in lithium-sulfur batteries and analyzes their electrochemical performance.

Deficient MoS2 nanoflowers to promote polysulfide redox conversion in Lithium-Sulfur batteries

The shuttle effect and the slow conversion kinetics hinder the practical application of lithium-sulfur batteries. Herein, we synthesized the polypyrrole (PPy) coated defect-rich MoS2 nanoflowers (PPy@DR-MoS2) as sulfur host. Benefiting from the sulfur defects and PPy coating structure, the S/ppy-DR-MoS2 composite displays good cycling performance at a high current density of 1C and excellent cycling stability for over 300 cycles with a low cycling decline rate of 0.17% per cycle.

Bifunctional K3PW12O40/Graphene Oxide-Modified Separator for Inhibiting Polysulfide Diffusion and Stabilizing Lithium Anode.

Lithium-sulfur (Li-S) batteries are considered as promising candidates for next-generation batteries due to their high theoretical energy density. However, the practical application of Li-S batteries is still hindered by several challenges, such as the polysulfide shuttle and the growth of lithium dendrites. Herein, we introduce a bifunctional K3PW12O40/graphene oxide-modified polypropylene separator (KPW/GO/PP) as a highly effective solution for mitigating polysulfide diffusion and protecting the lithium anode in Li-S batteries. By incorporating KPW into a densely stacked nanostructured graphene oxide (GO) barrier membrane, we synergistically capture and rapidly convert lithium polysulfides (LiPSs) electrochemically, thus effectively suppressing the shuttling effect. Moreover, the KPW/GO/PP separator can stabilize the lithium metal anode during cycling, suppress dendrite formation, and ensure a smooth and dense lithium metal surface, owing to regulated Li+ flux and uniform Li nucleation. Consequently, the constructed KPW/GO/PP separator delivered a favorable initial specific capacity (1006 mAh g-1) and remarkable cycling performance at 1.0 C (626 mAh g-1 for up to 500 cycles with a decay rate of 0.075% per cycle).

Reduced graphene oxide wrapped ZnCo layered double hydroxides microsphere as efficient sulfur host in lithium-sulfur batteries

The practical application of lithium-sulfur (Li-S) batteries is impeded by the shuttling of the polysulfide and slow sulfur electrochemical reaction. In this study, a reduced graphene oxide (rGO) wrapped hollow ZnCo layered double hydroxides (ZnCo-LDH) microsphere is fabricated as sulfur host material. The rGO nanosheets offer efficient charge transportation pathways. Meanwhile, the porous rGO and hollow ZnCo-LDH provide sufficient space for sulfur storage and mitigates the volume variation during battery charging and discharging. In addition, ZnCo-LDH exhibits excellent chemical adsorption capacity for polysulfides, and promotes their electrochemical conversion reactions. Benefited from these advantages, the S/ZnCo-LDH@rGO cathode delivers a high rate performance of 796.5 mAh g−1 at 5.0 C, and excellent stability performance with a capacity decay of 0.036 % per cycle after 500 cycles at 1.0 C. This study shows that the porous microsphere design of rGO wrapped layered double hydroxides has excellent application prospects as efficient sulfur host for Li-S batteries.

Investigation of the corrosion behavior influence of carbon interlayer on aluminum collector in lithium-sulfur battery system

Due to the shuttle effect brought by polysulfides, the commercialization of lithium-sulfur batteries still faces significant difficulties. Carbon interlayer is introduced to enhance the electrochemical performance of lithium-sulfur batteries, while the drawback that the interlayer will reversely affect the performance of the current collector was ignored. The current collector has a significant influence and contribution to the cycle stability of lithium-sulfur batteries. In this study, we looked into the electrochemical stability and corrosion situation of standard aluminum foil collectors in lithium-sulfur batteries with carbon interlayer. The results show that the introduction of carbon interlayer into the lithium-sulfur batteries will make aluminum foil and carbon paper form an electronic conduction path and galvanic corrosion occurs, accelerating the corrosion of aluminum foil. Therefore, we propose a new corrosion model. During the cycle, the surface of the aluminum collector becomes a non-dense passivation film and lithium polysulfide terminal (ST−1). Then, under the action of the carbon interlayer, the passivation film peels off and the oxide film is attacked by the electrolyte, thiosulfate and polythionate, resulting in pitting holes and ultimately accelerating the corrosion of the aluminum foil collector. This research has some guiding significance for the commercial application of lithium-sulfur batteries.

Beaded CoSe2-C Nanofibers for High-Performance Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries are regarded as highly promising energy storage devices due to their high theoretical specific capacity and high energy density. Nevertheless, the commercial application of Li-S batteries is still restricted by poor electrochemical performance. Herein, beaded nanofibers (BNFs) consisting of carbon and CoSe2 nanoparticles (CoSe2/C BNFs) were prepared by electrospinning combined with carbonization and selenization. Benefitting from the synergistic effect of physical adsorption and chemical catalysis, the CoSe2/C BNFs can effectively inhibit the shuttle effect of lithium polysulfides and improve the rate performance and cycle stability of Li-S batteries. The three-dimensional conductive network provides a fast electron and ion transport pathway as well as sufficient space for alleviating the volume change. CoSe2 can not only effectively adsorb the lithium polysulfides but also accelerate their conversion reaction. The CoSe2/C BNFs-S cathode has a high reversible discharge specific capacity of 919.2 mAh g-1 at 0.1 C and presents excellent cycle stability with a low-capacity decay rate of 0.05% per cycle for 600 cycles at 1 C. The combination of the beaded carbon nanofibers and polar metal selenides sheds light on designing high-performance sulfur-based cathodes.

Competing polysulfides conversion between edge-N and embedded CoS2 within multichannel carbon nanofibers

The practical application of lithium-sulfur batteries (LSBs) is hindered by a range of challenges, including slow conversion kinetics and inevitable shuttle effect of lithium polysulfide (LiPSs) intermediates, low electrical conductivity and rigorous volume expansion of sulfur. To address these challenges, we initiatively propose a competing catalytic mechanism dominated by two functional components, which aims to accelerate the liquid–liquid–solid conversion for the sulfur reduction reaction (SRR). To achieve this goal, we construct multichannel carbon fibers decorated with edge nitrogen and CoS2 nanoparticles (CoS2/NMCNF) as the cathode host for LSBs. The internal channels provide spatial constraints towards alleviating volume expansion and accelerating electron/ion transmission. Moreover, based on theoretical calculations and experiments, there is a competition between edge nitrogen and embedded CoS2 for catalytic conversion of LiPSs, of which CoS2 plays a major role in the liquid–liquid conversion (Li2S6–Li2S4), while edge-N accelerates the liquid–solid conversion (Li2S4–Li2S2). Consequently, the prepared CoS2/NMCNF electrode has an excellent performance with high initial specific capacity (1,437.9 mAh/g at 0.2C), excellent cycling stability at 3.0C (only about 0.032% capacity decay per cycle after 650cycles), and maintaining good cycling stability even when the sulfur loading increases to 4.10 mg cm−2. This work demonstrates a unique competing catalytic mechanism for the liquid–liquid–solid conversion process of LSBs.

Metallic Organic Framework (MOF) Applications in Novel Lithium-Sulfur Batteries

Today lithium-ion batteries are the basis of portable energy source. Wildly used in electronic devices and electric vehicles lithium-ion type of batteries became a standard. Despite good electrochemical performance and their universality, fast development of the market for efficient power sources makes them unable to meet this challenge. As a promising competitor or even a successor of lithium-ion batteries often named are lithium-sulfur batteries. It’s mostly because of their high specific capacity (1675 mAh g-1) and relatively big deposit of sulfur on Earth. The main reason, why this type of batteries is not commercialized yet is the problem with the application and stability of the sulfur electrode. The expansion of the sulfur when charging, its insulation and dissolution in organic solvents from the electrolyte, resulting the creation of polysulfides chains, are the remaining problems to solve before lithium-sulfur batteries could be spread in the commerce devices. To solve these issues many additives and compounds have been examined. One of the idea is to use metal-organic frameworks (MOFs) as a sulfur host on the electrode. Because of the porosity of the structure of these materials they are able to “hold” sulfur inside them. Not only it improves the electronic conductivity but also can be a solution to reduce the electrode expansion and sulfur reactions with electrolyte. This report presents a few methods of the possible ways of doping MOFs with sulfur and electrode slurry preparation. All the research was made in cooperation of Warsaw University of Technology from Poland and NTNU and SINTEF from Norway in M-ERA.NET 2 MOGLiS project.

Cooperative catalytic platinum species accelerating polysulfide redox reactions for Li-S batteries

The shuttle effect derived from diffusion of lithium polysulfides (LiPSs) and sluggish redox kinetic bring about poor cycling stability and low utilization of sulfur, which have always been the key challenging issues for the commercial application of lithium-sulfur (Li-S) batteries. Rational design of cathode materials to catalyze Li2S dissociation/nucleation processes is an appealing and valid strategy to develop high-energy practical Li-S batteries. Herein, considering the synergistic effect of bidirectional catalysis on LiPSs conversion and enhanced chemical immobilization for LiPSs by heteroatom doping, Pt nanoparticles loaded on nitrogen-doped carbon spheres (Pt/NCS composites) were constructed as cathode materials. According to the dynamic evolution of Pt catalysts and sulfur species, Pt0 and Pt2+ species were identified as active species for the accelerated dissociation and nucleation of Li2S, respectively. Meanwhile, in-situ Raman results demonstrated the expedited conversion of sulfur species resulted from bidirectional catalysis of active Pt species, corresponding to boosted redox kinetics. Consequently, Pt/NCS cathode exhibited improved long-term cyclability with high initial capacity, along with enhanced rate capability. This work provides a facile approach to construct cathode materials with bidirectional catalysis on Li2S dissociation/nucleation, and sheds light on a more global understanding of the catalytic mechanism of metal catalysts during LiPSs conversion.

Vanadium as Auxiliary for Fe-V Dual-Atom Electrocatalyst in Lithium-Sulfur Batteries: "3D in 2D" Morphology Inducer and Coordination Structure Regulator.

The undesirable shuttling behavior, the sluggish redox kinetics of liquid-solid transformation, and the large energy barrier for decomposition of Li2S have been the recognized problems impeding the practical application of lithium-sulfur batteries. Herein, inspired by the spectacular catalytic activity of the Fe/V center in bioenzyme for nitrogen/sulfur fixation, we design an integrated electrocatalyst comprising N-bridged Fe-V dual-atom active sites (Fe/V-N7) dispersed on ingenious "3D in 2D" carbon nanosheets (denoted as DAC), in which vanadium induces the laminar structure and regulates the coordination configuration of active centers simultaneously, realizing the redistribution of the 3d-orbital electrons of Fe centers. The high coupling/conjunction between Fe/V 3d electrons and S 2p electrons shows strong affinity and enhanced reactivity of DAC-Li2Sn (1 ≤ n ≤ 8) systems. Thus, DAC presents strengthened chemisorption ability toward polysulfides and significantly boosts bidirectional sulfur redox reaction kinetics, which have been evidenced theoretically and experimentally. Besides, the well-designed "3D in 2D" morphology of DAC enables uniform sulfur distribution, facilitated electron transfer, and abundant active sites exposure. Therefore, the assembled Li-S cells present outstanding cycling stability (637.3 mAh g-1 after 1000 cycles at 1 C) and high rate capability (711 mAh g-1 at 4 C) under high sulfur content (70 wt %).

VS4/MoS2 heterostructures grown along graphene to boost reaction kinetics and reversibility for high performance lithium-sulfur batteries

Lithium-sulfur batteries are regarded as one of the most promising next-generation energy storage systems due to their high theoretical volumetric and high weight energy density. However, there are severe problems in the application of lithium-sulfur batteries. The shuttle effect of soluble lithium polysulfide (LiPs) and the low conductivity of sulfur, which leads to slow redox kinetics, are hindering the more significant application of lithium-sulfur batteries. One of the viable solutions to the cathode problem of lithium-sulfur batteries is heterostructured materials. The built-in electric field provided by the heterostructure can significantly accelerate the kinetics of charge transport. In this work, we constructed a heterogeneous structure of G-VS4/MoS2 composites(PVM) modified by Polyvinylpyrrolidone(PVP) is constructed based on graphene, which consists of VS4 nanosheets and MoS2 nanosheets grown vertically on graphene lamellae. With weak van der Waals interactions, the one-dimensional (1D) chain-like VS4 crystal structure enables fast charge transfer in Li-ion batteries. The two-dimensional (2D) lamellar MoS2 crystals contain Mo-S bonds that also have adsorption effects on polysulfides. Density functional theory (DFT) calculations show that VS4 and MoS2 can increase the binding energy of the anode to the polysulfide. Therefore, the S@PVM cathode material provides a large capacity of 1061.4 mAh/g at 0.5 C and can still get to 808.3 mAh/g after 400th cycles. A capacity retention rate of 76.15% is obtained at the same time. It can also boast an initial discharge capacity of 834.8 mAh/g at 1 C. These works can provide more thoughts for developing cathode materials for lithium-sulfur batteries.

CoS2 embedded 3D hollow carbon spheres nanoreactors for high-performance lithium-sulfur batteries

Lithium-sulfur batteries have high theoretical specific capacity benefitting from their own multiple electrons participating in redox reactions, which has attracted wide attention. Whereas, the poor conductivity, shuttle effect and volume expansion hinder the commercial application of lithium-sulfur batteries. Herein, a novel N/S-codoped 3D hollow carbon spheres embedded CoS2 nanoreactors are elaborated, which have competition advantages. Due to the synergistic chemisorption of doped heteroatom sites and polar CoS2 nanoparticles, the nanoreactors have strong adsorption capacity to lithium polysulfides (LiPSs). The 3D hollow graphitized carbon spheres with highly electrical conductivity facilitates fast sulfur electrochemistry redox reaction. The competition advantages effectively improve the performance of the lithium sulfur batteries. Accordingly, the S@CoS2NHGC cathode exhibits excellent specific capacity. It shows excellent electrochemical properties, such as 1570 mAh g−1 at 0.05 C, high cycle stability and Coulombic efficiency at 5 C, and outstanding rate performance at 10 C. We provide a reasonably designed strategy and fully explore the mechanism of improving the performance of Li-sulfur battery.

Multifunctional Ni-doped CoSe2 nanoparticles decorated bilayer carbon structures for polysulfide conversion and dendrite-free lithium toward high-performance Li-S full cell

The commercial application of lithium-sulfur batteries is severely hampered by polysulfide shuttle effects, sluggish redox kinetics, and uncontrollable lithium dendrite growth. Herein, a unique Ni-doped CoSe2 nanoparticle decorated bilayer carbon (Ni-CoSe2/BC) structure is synthesized for both the sulfur cathode and lithium anode, which introduces bi-functionalities including Ⅰ) the internal carbon conductive network skeleton of carbon nanotubes is capable of physically confining, storing, and alleviating volume expansion of sulfur; and Ⅱ) Ni-CoSe2 nanoparticles decorated on the external carbon nanoarrays contribute to efficient chemical anchoring and accelerated polysulfide conversion for the cathode, and serve as lithiophilic sites to induce homogeneous lithium deposition for the anode. As a result, Ni-CoSe2/BC effectively inhibits the shuttle effect and induces dendrite-free lithium deposition. The Ni-CoSe2/BC-S delivers a high discharge specific capacity of 806 mAh g−1 after 400 cycles at 1 C, with a low capacity decay rate of 0.07% per cycle. Moreover, the Ni-CoSe2/BC-Li exhibits an impressively long cycle life of 2000 h at 10 mA cm−2/10 mAh cm−2. Notably, the lithium-sulfur full cell assembled with Ni-CoSe2/BC as universal hosts for both anode and cathode possesses an average discharge capacity of 6.07 mAh cm−2 in 50 cycles (Sulfur loading=12.8 mg cm−2, Electrolyte/Sulfur=7.8 μL mg−1, and Negative/Positive=1.56). This work provides novel structural design and mechanism insights for the practical application of lithium-sulfur batteries.

Dual Network Electrode Binder toward Practical Lithium–Sulfur Battery Applications

Dual Network Electrode Binder toward Practical Lithium–Sulfur Battery Applications

Sub-nanometer cobalt clusters embedded carbon networks to promote the kinetics of polysulfide conversion

The sluggish oxidation-reduction kinetics of sulfur and the shuttle effect of polysulfides are the bottlenecks restricting the practical application of lithium-sulfur batteries. In this study, subnanometer cobalt clusters were embedded into the cross-linked network of carbon sheets framework as high-efficiency sulfur host materials to promote the kinetics of polysulfides conversion for lithium-sulfur batteries. In such composite structure, the carbon network provides a rapid electron transfer pathway for interfacial electrochemical reaction. Co and N atoms can chemisorb polysulfides by forming Co-S and Li-N bonds with polysulfides, and catalyze the conversion of polysulfides. Such structure exhibits excellent rate performance and cycle stability during the cycle of lithium-sulfur battery. The capacity decay rate per cycle is only 0.061% for 500 cycles at 1 C, and the capacity retention rate is 69.4%. The composite structure developed in this work is a promising and high-efficiency sulfur host for lithium-sulfur batteries.

An Endogenous Prompting Mechanism for Sulfur Conversions Via Coupling with Polysulfides in Li-S Batteries.

The sluggish kinetics process and shuttling of soluble intermediates present in complex conversion between sulfur and lithium sulfide severely limit the practical application of lithium-sulfur batteries. Herein, by introducing a designated functional organic molecule to couple with polysulfide intermediators, an endogenous prompting mechanism of sulfur conversions has thus been created leading to an alternative sulfur-electrode process, in another words, to build a fast "internal cycle" of promotors that can promote the slow "external cycle" of sulfur conversions. The coupling-intermediators between the functional organic molecule and polysulfides, organophosphorus polysulfides, to be the "promotors" for sulfur conversions, are not only insoluble in the electrolyte but also with higher redox-activity. So the sulfur-electrode process kinetics is greatly improved and the shuttle effect is eliminated simultaneously by this strategy. Meanwhile, with the endogenous prompting mechanism, the morphology of the final discharge product can be modified into a uniform covering film, which is more conducive to its decomposition when charging. Benefiting from the effective mediation of reaction kinetics and control of intermediates solubility, the lithium-sulfur batteries can act out excellent rate performance and cycling stability.

Mott-Schottky MXene@WS2 Heterostructure: Structural and Thermodynamic Insights and Application in Ultra Stable Lithium-Sulfur Batteries.

Due to the "shuttle effect" and low conversion kinetics of polysulfides, the cycle stability of lithium sulfur (Li-S) battery is unsatisfactory, which hinders its practical application. The Mott-Schottky heterostructures for Li-S batteries not only provide more catalytic/adsorption active sites, but also facilitate electrons transport by a built-in electric field, which are both beneficial for polysulfides conversion and long-term cycle stability. Here, MXene@WS2 heterostructure was constructed by in-situ hydrothermal growth for separator modification. In-depth ultraviolet photoelectron spectroscopy and ultraviolet visible diffuse reflectance spectroscopy analysis reveals that there is an energy band difference between MXene and WS2 , confirming the heterostructure nature of MXene@WS2 . DFT calculations indicate that the Mott-Schottky MXene@WS2 heterostructure can effectively promote electron transfer, improve the multi-step cathodic reaction kinetics, and further enhance polysulfides conversion. The built-in electric field of the heterostructure plays an important role in reducing the energy barrier of polysulfides conversion. Thermodynamic studies reveal the best stability of MXene@WS2 during polysulfides adsorption. As a result, the Li-S battery with MXene@WS2 modified separator exhibits high specific capacity (1613.7 mAh g-1 at 0.1 C) and excellent cycling stability (2000 cycles with 0.0286 % decay per cycle at 2 C). Even at a high sulfur loading of 6.3 mg cm-2 , the specific capacity could be retained by 60.0 % after 240 cycles at 0.3 C. This work provides deep structural and thermodynamic insights into MXene@WS2 heterostructure and its promising prospect of application in high performance Li-S batteries.