Interlayer For Lithium-sulfur Batteries Research Articles

Crystalline and amorphous Fe2O3 nanocubes grown on electrospun carbon nanofibers for lithium-ion batteries and lithium-sulfur batteries: A comparative study

Amorphous transition metal oxides have recently received particular research interests in electrochemical energy storage. However, there is still a lack of direct comparisons between amorphous materials and their crystalline counterparts. Here, we demonstrate the rational synthesis of crystalline and amorphous Fe2O3 nanocubes uniformly grown on carbon nanofibers (denoted as CNFs@C-Fe2O3 and CNFs@A-Fe2O3, respectively) for lithium-ion batteries (LIBs) and lithium-sulfur batteries (LSBs). In such a structure, the Fe2O3 nanocubes possess strong interfacial bonding with CNFs, which can ensure rapid electron transportation. Besides, these Fe2O3 nanocubes are highly porous, which can effectively alleviate the volume change, enlarge the surface area, increase active sites and facilitate ion diffusion. When employed as freestanding anode for LIBs, the CNFs@C-Fe2O3 electrode delivers much improved lithium ion storage performance compared to that of CNFs@A-Fe2O3. When evaluated as interlayers for LSBs, instead, the batteries with CNFs@A-Fe2O3 exhibit better rate performance cycling stability than that of with CNFs@C-Fe2O3. Moreover, theoretical calculations elucidate the amorphous Fe2O3 has stronger adsorption ability toward the soluble lithium polysulfides. This work would provide new insights into the reasonably development of crystalline and amorphous transition metal oxides toward electrochemical energy storage.

NiS/NiCo2 O4 Cooperative Interfaces Enable Fast Sulfur Redox Kinetics for Lithium-Sulfur Battery.

Due to their high energy density and cost-effectiveness, lithium-sulfur batteries (LSBs) are considered highly promising for the next generation of energy storage technologies. However, the soluble lithium-polysulfides (LiPSs) notorious for causing the shuttle effect and the sluggish redox kinetics have hindered their practical commercialization. To tackle these challenges, a heterostructural catalyst featuring NiS-NiCo2 O4 interfaces is developed, which serves as an interlayer for LSBs. These interfacial sites leverage the advantages of polar NiCo2 O4 and conductive NiS, enabling smooth Li+ diffusion, rapid electron transport, and effective immobilization of LiPSs. This synergistic approach promotes the conversion of sulfur species, resulting in a high discharge capacity of 526mAhg-1 at 3C for cells with the NiS-NiCo2 O4 interlayer. Additionally, remarkable cycling stability is achievable with an areal sulfur loading of ≈5.0mgcm-2 . It is believed that this research paves the way for practical applications of LSBs.

Accelerated polysulfide conversion using nitrogen-doped carbon nanofibers embedded with V2O3 as interlayers for lithium-sulfur batteries

Accelerated polysulfide conversion using nitrogen-doped carbon nanofibers embedded with V2O3 as interlayers for lithium-sulfur batteries

Flexible Hierarchical Co‐Doped NiS2@CNF‐CNT Electron Deficient Interlayer with Grass‐Roots Structure for Li–S Batteries

AbstractThe key means to improve the performance of lithium–sulfur batteries (LSBs) is to reduce the internal resistance by building an electronic/ionic pathway and to accelerate the conversion kinetics of lithium polysulfides (LiPSs) through modulation of interface functions. Herein, inspired by a grass root system, a flexible hierarchical CNF‐CNT (carbon nanofiber‐carbon nanotube) membrane decorated with Co‐doped NiS2nanoparticles (Co‐NiS2@CNF‐CNT) is designed as an interlayer for LSBs, in which the in situ grown CNTs (root hairs) are wound on CNF (roots). Density functional theory (DFT) calculations show that Co doping introduces electron‐deficient regions at the doping sites in NiS2, thus improving chemical adsorption and catalytic activities toward LiPSs. The cell pairs with the Co‐NiS2@CNF‐CNT interlayer exhibit a high rate performance of 951.4 mAh g−1at 3 C, a reversible capacity of 944.1 mAh g−1after 500 cycles at 0.2 C, and a prolonged cycle life of 3000 cycles at 5 C. More importantly, an areal capacity of 7.96 mAh cm−2is achieved with a sulfur loading of 9.6 mg cm−2. This work provides a strategy for enhancing the electrochemical performance of LSBs by combining 3D hierarchical conductive skeletons and electron‐deficient functional adsorption and catalysis materials.

Nitrogen-doped 3-D porous carbon network derived from lotus leaves as interlayer for lithium sulfur batteries

Various nitrogen doped 3-D porous carbon networks (PCNs) were prepared by a facile hydrothermal treatment of lotus leaves using urea and dicyandiamide (DCDA) as the nitrogen agent. The un-doped and N-doped PCNs were used as an interlayer for lithium sulfur batteries. The N-doped PCNs prepared by urea exhibited a maximum surface area and broader pore size distribution due to formation of more defects. After 100 charge-discharge cycles the improved discharge capacity and capacity retention were obtained. Surprisingly, a superior rate performance was observed. Under 5 C rate the N-doped interlayers exhibited the higher discharge capacity of 442 mA h g−1 than the undoped interlayers, 293 mA h g−1 and the N-doped interlayer by DCDA, 370 mA h g−1. This was associated with the enhanced lithium ion diffusivity and reduced charge transfer resistance, resulting from the presence of more pyridinic-N and pyrrolic-N and appropriate pore size distribution that enabled to capture more soluble lithium polysulfide.

Hierarchical lamellar single-walled carbon nanotube aerogel interlayers for stable lithium-sulfur batteries with high-sulfur-loading

Lithium-sulfur (Li-S) battery has been recognized as a new energy storage device with broad prospects because of its satisfactory specific capacity and theoretical energy density. Nevertheless, the shuttle effect of polysulfides seriously hinders the real applications of high-sulfur-loaded Li-S batteries. To remove the hurdle, hierarchical lamellar single-walled carbon nanotube aerogels (SWCNTAs) are herein fabricated and applied as multifunctional interlayers in Li-S batteries, which exhibit an initial area-specific capacity as high as 7.1 mAh cm−2 at a sulfur loading of 8.02 mg cm−2. The introduced SWCNTA interlayers can lower the internal resistance and suppress the shuttling of polysulfides by a layer-by-layer physical blocking mechanism. Moreover, owing to the super wettability of SWCNTAs, electrolytes with a dosage of 10 μL mg−1 could effectively wet and infiltrate the interlayers, rendering the lean-electrolyte Li-S batteries a high specific capacity of 559 mAh g−1 at a sulfur loading of 10.35 mg cm−2 after 60 cycles. This work presents an example for rationally designing the interlayers structures for high-sulfur loading batteries, which paves a stepping stone for the future commercialization of Li-S batteries.

Carbon nanofibers embedded with tiny CoNi bimetals as the functional interlayer for high-performance lithium–sulfur batteries

Free-standing carbon nanofibers have been recognized as an effective interlayer to improve sulfur cathode electronic conductivity and inhibit shuttling of polysulfides. However, carbon materials show a limited effect on improving electrochemical performance of lithium–sulfur batteries (LSBs) due to their nonpolar and weak physical limitations for the dissolvable polysulfides. It has been reported that introducing chemical bonds between polar compounds and polysulfides helps to suppress the shuttle effect of polysulfides via combining physical confinement with chemical adsorption. Herein, free-standing N-doped carbon nanofibers embedded with bimetallic CoNi (CoNi@N-CNFs) are constructed as an interlayer for LSBs. Apart from improving electronic conductivity of the sulfur cathode, the CoNi@N-CNF interlayer also displays excellent adsorption ability to the dissolvable polysulfides and promotes conversion reactions between sulfur species. Under the synergistic effect of the carbon framework and CoNi bimetals, the CoNi@N-CNF interlayer achieves decent electrochemical performance with a high initial discharge capacity of 1563 mAh g−1 at 0.2C and 0.53% capacity decay per cycle during 100 cycles.

Progress and Opportunities of Vanadium-Based Compounds as Cathode Hosts, Decoration Layers of Separators, and Interlayers in Lithium Sulfur Batteries

Progress and Opportunities of Vanadium-Based Compounds as Cathode Hosts, Decoration Layers of Separators, and Interlayers in Lithium Sulfur Batteries

Constructing MIL-101(Cr) membranes on carbon nanotube films as ion-selective interlayers for lithium-sulfur batteries.

It is of significant importance to suppress the polysulfide shuttle effect for the commercial application of lithium-sulfur batteries. Herein, continuous MIL-101(Cr) membranes were successfully fabricated on carbon nanotube films utilizing a simple in-situ growth method, aiming at constructing interlayer materials for inhibiting the shuttle effect. Owing to the suitable pore aperture and super electrolyte wettability, the as-developed MIL-101(Cr) membrane can effectively inhibit the shuttle behaviour of polysulfides while allowing the fast transport of Li-ions simultaneously, working as an ionic sieve. Additionally, this MOFs membrane is also helpful in accelerating the polysulfide catalytic conversion. Therefore, the proposed interlayer delivers an extraordinary rate capability, showing a remarkable capacity of 661.9 mAh g-1 under 5 C. Meanwhile, it also exhibits a high initial capacity of 816.1 mAh g-1 at 1 C and an exceptional durability with an extremely low capacity fading of 0.046 % per cycle over 500 cycles.

Highly catalytic porous MoN nanosheets anchored carbon microtubes interlayer for lithium-sulfur batteries

Lithium-sulfur batteries (LSBs) have been widely considered as one of the most promising next-generation energy storage devices owing to the ultrahigh theoretical capacity (1,672 mAh/g) and energy density (2,600 Wh/kg). However, the shuttle effect of lithium-polysulfides (LiPSs) and the sluggish conversion kinetics impede the wide commercialization of LSBs. In this work, porous and catalytic MoN nanosheets were fabricated on the conductive carbonized cotton cloth (denoted as CCC@MoN) to serve as an interlayer for LSBs. The porous structure of MoN nanosheets provides abundant catalytic sites to capture LiPSs and accelerates conversion kinetics. Notably, hollow and conductive fibers in CCC substrate can physically restrain LiPSs and serve as a secondary current collector to recycle the dissolved sulfur species. Thus, the highly catalytic porous MoN and conductive CCC can synergistically generate an efficient trapping-conversion ability toward polysulfides. With the assistance of the CCC@MoN interlayer, the LSBs exhibit remarkable cycling stability and rate performance. Even with a high areal sulfur loading (5 mg/cm−1) cathode, an impressive areal specific capacity of 4 mAh/cm−1 can still be achieved at 0.1 C. This work paves a new way for the design of multifunctional interlayers in the commercial application of LSBs.

Electrically and Thermally Conductive Al2o3/C Nanofiber Membrane Filled with Organosilicon as a Multifunctional Integrated Interlayer for Lithium-Sulfur Batteries Under Lean-Electrolyte and Thermal Gradient

Electrically and Thermally Conductive Al2o3/C Nanofiber Membrane Filled with Organosilicon as a Multifunctional Integrated Interlayer for Lithium-Sulfur Batteries Under Lean-Electrolyte and Thermal Gradient

Graphene-based interlayer for high-performance lithium–sulfur batteries: A review

Lithium–sulfur (LiS) batteries have been widely studied, and considered as one of the most promising energy storage systems, because of their superior theoretical energy density, non-toxicity, high abundance, and environmental friendliness. However, LiS batteries suffer from problems such as the electrical insulating characteristic of sulfur and unsatisfactorily long cycling life. As a superior type of carbon material, graphene have been intensively investigated as intermediate layers to overcome these problems because of its large surface area, good chemical stability, and excellent electrical conductivity. In this review, we summarize the recent application of graphene-based materials, including simple graphene and graphene-based nanocomposites, as modifying interlayers in LiS batteries. Furthermore, the strategies to enhance their electrochemical performance are summarized and discussed, for example, physical and chemical confinement. Finally, the limitation and challenges of graphene-based materials as interlayers for LiS batteries, as well as their prospects for future research, are proposed. We hope that this review will be helpful for scientists to design and fabricate high-performance LiS batteries based on graphene-based interlayers and boost their practical applications.

Laser-Ablated Red Phosphorus on Carbon Nanotube Film for Accelerating Polysulfide Conversion toward High-Performance and Flexible Lithium-Sulfur Batteries.

The use of a conducting interlayer between separator and cathode is one of the most promising methods to trap lithium polysulfides (LiPSs) for enhancing the performance of lithium-sulfur (Li-S) batteries. Red phosphorus nanoparticles (RPEN )-coated carbon nanotube (CNT) film (RPEN @CF) is reported herein as a novel interlayer for Li-S batteries, which shows strong chemisorption of LiPSs, good flexibility, and excellent electric conductivity. A pulsed laser ablation method is engaged for the ultrafast production of RPEN of uniform morphology, which are deposited on the CNT film by a direct spinning method. The RPEN @CF interlayer provides pathways for effective Li+ and electron transfer and strong chemical interaction with LiPSs. The S/RPEN @CF electrode shows a superior specific capacity of 782.3mAhg-1 (3C-rate) and good cycling performances (769.5mAhg-1 after 500 cycles at 1C-rate). Density functional theory calculations reveal that the morphology and dispersibility of RPEN are crucial in enhancing Li+ and electron transfer kinetics and effective trap of LiPSs. This work demonstrates the possibility of using the RPEN @CF interlayer for the enhanced electrochemical performances of Li-S batteries and other flexible energy storage devices.

Super-aligned films of sub-1 nm Bi2O3-polyoxometalate nanowires as interlayers in lithium-sulfur batteries

Sub-1 nm nanowires (SNWs) can not only be processed like polymers due to their polymer-analogue properties but also show multifunctions owing to their well-manipulated compositions and structures. Rationally designed and engineered multicomponent heterostructure SNWs can further enhance their multifunction performance while it is very challenging to achieve such SNWs at sub-nanoscale. Herein, we synthesized Bi2O3-polyoxometalate heterostructure SNWs (PMB SNWs), and fabricated super-aligned PMB SNWs films (S-PMB SNWs films), which can serve as interlayers to efficiently suppress lithium polysulfide (LPS) shuttling, intrinsically promote the redox kinetics of the LPS conversion and substantially protect the Li anode. The lithium-sulfur (Li-S) battery with the S-PMB SNWs film as the interlayer showcases an ultralow capacity decay rate with 0.013% per cycle over 850 cycles. This study demonstrates the potential of heterostructure SNWs to improve the performance of Li-S batteries.

Carbon nanotube-supported MoSe2 nanoflakes as an interlayer for lithium-sulfur batteries

Carbon nanotube-supported MoSe2 nanoflakes as an interlayer for lithium-sulfur batteries

Carbon nanotube-supported MoSe2 nanoflakes as an interlayer for lithium-sulfur batteries

Intrinsic polysulfide shuttling is the most fatal problem with Li-S batteries but it can be suppressed by functionalizing the separators with strong lithium polysulfide absorbents. Carbon nanotube (CNT)-supported MoSe2 nanoflakes with a large interlayer spacing were coated on a commercial polypropylene separator to build an efficient barrier (M/C-PP) to polysulfide shuttling for Li-S batteries. The battery with the separator had initial specific capacities of 1 485 and 880 mAh g−1 at 0.1 and 2 C, respectively, and an excellent long-term cycling stability with a low decay rate of 0.093% per cycle at 0.5 C after 300 cycles. This excellent performance was attributed to the strong adsorption of polysulfides by MoSe2 and the fast charge transport channels provided by the CNTs.

Electrospun-cellulose derived free-standing carbon nanofibers as lightweight, ultrathin, and stackable interlayers for lithium-sulfur batteries

The insertion of an interlayer between the separator and cathode is considered a promising strategy to improve the conductivity as well as suppress the polysulfide shuttling effect in lithium-sulfur batteries (LSBs). However, the fundamental disadvantages of loss in weight/volume capacity and high cost upon the addition of an interlayer brings significant challenges. Herein, we report free-standing carbon nanofibers based on electrospun-cellulose (ACCF) as a lightweight (0.38 mg cm−2) and ultrathin (10 μm) interlayer for LSBs. The unique semi-carbonization of cellulose precursors provides a large surface area (2665.2 m2 g−1) and high conductivity (6.5 S cm−1) to overcome the conductivity–surface area trade-off in conventional interlayers. Interestingly, the high wettability of ACCF is induced by the functional groups in cellulose, which decreases the electrolyte demand and enables the material to be stacked into multiple layers. This allows a conceptual study providing the scientific clue for the critical material factor in the LSB interlayer. Benefitting from its multi-functional characteristics, ACCF-modified cell provides a high specific capacity of 1403 mA h g−1 and a remarkable areal capacity 4.83 mA h cm−2 (S loading 4.6 mg cm−2) at 0.1C. Therefore, this innovative, cheap, and scalable ACCF can be used as a practical interlayer toward the commercialization of high-energy LSBs.

TiO2 embedded hydrothermally synthesized carbon composite as interlayer for lithium-sulfur batteries

Lithium-sulfur battery chemistry is one of the best alternatives to meet the demand of future electric vehicles providing high theoretical capacity and energy density. However, Li-S batteries suffer from internal issues, most of which is due to the shuttle effect that mitigates their commercial availability. In this work, TiO2/carbon composite is synthesized by hydrothermal carbonization and used as interlayer to alleviate the shuttle effect. This interlayer is used without further pyrolysis in order not to lose the benefit of the functional groups of carbonaceous material which help in adsorbing polysulfides. Moreover, TiO2 chemically binds polysulfides and boosts the adsorbing ability of the interlayer on polysulfides to a large extent. In consequence of this approach, 630 mAh/g discharge capacity is obtained after 100 cycles at C/5 current density. The adsorption ability of the interlayer ending up with enhanced electrochemical performance is proven by XPS with the significant shifts in binding energies.

Metal-organic-framework-derived 3D crumpled carbon nanosheets with self-assembled CoxSy nanocatalysts as an interlayer for lithium-sulfur batteries

Two-dimensional (2D) nanosheets are promising interlayers for enhancing the electrical conductivity and hindering the lithium polysulfide (LPS) shuttling in lithium–sulfur batteries (LSB). However, their dense 2D nature limits the electrolyte infusion and lithium ion transport, thereby decreasing the rate performance. Herein, we demonstrate that three-dimensional (3D) crumpled carbon nanosheets (CCNSs) decorated with a few nanometers of cobalt heterostructures (CoxSy) that are based on a 2D zeolitic imidazolate framework can improve both the LPS adsorption as well as the ion conduction of LSB interlayer. The method is simple and scalable; the 3D composites are fabricated by post-annealing of 2D metal organic frameworks, which are synthesized by a solution process at room temperature without surfactant. Interestingly, the assembly and polarity of cobalt heterostructures can be further manipulated by the annealing condition; this provides a scientific evidence for the nanostructural and compositional combination of polar compounds. Consequently, CoS/Co9S8@CCNS exhibits the best performance with a discharge capacity of 911 mA h g−1 at 0.2C after 100 cycles (150% more than commercial sulfur cell) and the long-term cyclability of 600 mA h g−1 at 1C after 500 cycles. This is attributed to efficient charge transfer as well as effective LPS adsorption and effective catalytic conversion; further, this is achieved by the synergetic effects of well-distributed polar compounds comprising few nanometers in size and optimal polarity on a highly conductive N-doped carbon nanosheet.

Efficient polysulfide trapping enabled by a polymer adsorbent in lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries have been viewed as promising candidates for next-generation high-energy rechargeable batteries due to their high theoretical energy density. However, their practical application is severely impeded by the notorious shuttle effect of soluble polysulfides. Herein, a nature polymer of konjac glucomannan (KGM) was adopted as polysulfide-adsorbing agent by coating on carbon nanofiber (CNF) mats for polysulfide-trapping interlayers in Li-S batteries. A uniform coating method was developed by improving the wettability of CNFs to aqueous solutions using ethanol as a co-solvent of water. It is revealed that not only the KGM polymer itself but also the coating quality is critical to prevent polysulfide diffusion. With the improved coating quality and the strong chemisorption of KGM, the shuttle effect was effectively suppressed and excellent electrochemical performance was demonstrated with a high reversible capacity of 1286 mAh g−1 at 0.2C, good cycling stability with a capacity retention of 84% after 400 cycles at 1C and high rate capability. Our findings provide a facile way to address the shuttle behavior of Li-S batteries using low-cost and environmental friendly materials, which are very promising for large-scale energy storage applications.