Uniform Distribution Of Sulfur Research Articles

Engineering Triple-Phase Interfaces with Hierarchical Carbon Nanocages for High-Areal-Capacity All-Solid-State Li-S Batteries.

All-solid-state lithium-sulfur batteries (ASSLSBs) have garnered widespread attention due to their advantages of high energy density and enhanced safety. However, the typical composite structure composed of solid-state electrolyte (SE), discrete conducting carbon black, and microsized sulfur (μ-S) with long-range Li+/e- conducting path and huge volume changes, suffers from sluggish charge transport and severe electrochemical-mechanical failure. In this work, a unique hierarchical carbon nanocage (hCNC) is applied as a continuous conducting network where nanosized sulfur are confined. Due to the synergistic effects of multi-dimensional (particle, interface, and electrode) structural engineering, this new sulfur-carbon composite cathode (S@hCNC39) can achieve uniform distribution of sulfur and carbon, and efficiently constructs triple-phase interfaces, showing enhanced charge-carrier transport and improved electrochemical-mechanical stability. Remarkable cycling performance of 89% after 300 cycles at 0.2C at 30°C is realized in ASSLSBs assembled with S@hCNC39. Notably, ASSLSBs achieve an ultrahigh areal capacity of 9.95 mAh cm-2 with stable cycling at 60°C with high sulfur contents of 40% and high sulfur loadings of 6mg cm-2. These results provide critical insights into the design of rational sulfur-carbon composites and offer a viable approach to enhance the overall performance of ASSLSBs.

Ultrafast microwave synthesis of MoSSe@ graphene composites via dual anion design for long-cyclable Li-S batteries

Lithium-sulfur batteries (LSBs) have been increasingly recognized as a promising candidate for the next-generation energy-storage systems. This is primarily because LSBs demonstrate an unparalleled theoretical capacity and energy density far exceeding conventional lithium-ion batteries. However, the sluggish redox kinetics and formidable dissolution of polysulfides lead to poor sulfur utilization, serious polarization issues, and cyclic instability. Herein, sulfiphilic few-layer MoSSe nanoflake decorated on graphene (MoSSe@graphene), a two-dimensional and catalytically active hetero-structure composite, was prepared through a facile microwave method, which was used as a conceptually new sulfur host and served as an interfacial kinetic accelerator for LSBs. Specifically, this sulfiphilic MoSSe nanoflake not only strongly interacts with soluble polysulfides but also dynamically promotes polysulfide redox reactions. In addition, the 2D graphene nanosheets can provide an extra physical barrier to mitigate the diffusion of lithium polysulfides and enable much more uniform sulfur distribution, thus dramatically inhibiting polysulfides shuttling meanwhile accelerating sulfur conversion reactions. As a result, the cells with MoSSe@graphene nanohybrid achieved a superior rate performance (1091 mAh/g at 1C) and an ultralow decaying rate of 0.040 % per cycle after 1000 cycles at 1C.

Insights into the removal of volatile organic compounds by three-dimensional ordered microporous zeolite-templated carbon: A combined experimental study and density functional theory calculation

Volatile organic compounds (VOCs) threaten human health and the ecological environment, requiring to be removed timely. Zeolite-templated carbon with and without sulfur (ZTC and S-doped ZTC) was prepared by the chemical vapor deposition (CVD) method in a rotating bed reactor and used to remove VOCs. ZTC samples showed narrow and ordered microporous structure (0–2 nm), high specific surface area (2049.05–1732.06 m2/g), abundant pore volume (1.28 – 1.16 cm3/g), and uniform sulfur distribution (S-doped ZTC). Afterwards, the VOCs adsorption capacity was tested at 30, 60, and 90 °C. The results showed that S-doped ZTC exhibited higher benzene (138.2 mg/g) and toluene (171.8 mg/g) adsorption capacities at 30 °C than those performed at 60 and 90 °C owing to the exothermic process. Moreover, S-doped ZTC showed better VOCs adsorption capacity than ZTC-RC due to the combination of physical and weak chemical adsorption. Subsequently, S-doped ZTC captured more toluene (171.8 mg/g) than benzene (138.2 mg/g) because of the dipole–dipole interaction. Furthermore, Fourier transform infrared spectrum (FTIR) and density functional theory (DFT) calculation revealed that inorganic components (NH3, NO, and SO2) imposed a negative effect on VOCs adsorption due to the comparative adsorption. This study offered insights into how ZTC structure and sulfur modification affected the adsorption of VOCs, providing a reliable guideline for the preparation and utilization of adsorbents used to remove VOCs.

Surface modification of commercial carbon black by silane coupling agents for improving dispersibility in rubber compounds

AbstractThe dispersion of a filler in a rubber matrix is a crucial parameter affecting the mechanical and dynamical properties of a rubber compound. It is the current issue of the rubber compounding industry because, most fillers are categorized as a mineral, while the rubber is an organic material. The surface modification of the filler has been accepted as an effective technique for the improvement of the abovementioned parameter. First, the surface premodification of commercial carbon black with a grade of N660 (CB) was implemented by four different oxidation methods. After that, among of used methods, the oxidation method using citric acid was selected to produce modified carbon black (CB‐Oxi) for further treatment. Subsequently, the coupling agent, Bis[3‐(triethoxysilyl)propyl] tetrasulfide (TESPT) was functionalized on the surface of CB‐Oxi to produce modified‐CB‐Oxi. Also, for comparison purposes, the TESPT functionalization was accomplished on untreated CB to form modified‐CB. The FTIR spectra of CB‐Oxi showed using the premodification method introduced the hydroxyl and carboxyl groups on the surface of CB. The correspondent spectra for modified‐CB‐Oxi confirmed the existence of silane groups on the surface of the carbon black. However, the mentioned silane groups were not observed on the surface of modified‐CB. The findings were strengthened by several characteristic techniques including, FESEM, XRD, EDS, CHNS elemental analysis, and RAMAN spectra. The FESEM graphs and elemental mapping showed homogeneous dispersion and uniform distribution of sulfur and silicon elements on the modified‐CB‐Oxi surface. According to RAMAN spectra, the disturbance in the structure of carbon black graphite was reduced after surface modification. modified‐CB‐Oxi is proposed as a potential substitute filler for current commercial carbon black in rubber compounding.

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 %).

Hierarchical hybrid architecture of carbon nanotube branches grown onto steam activated-reduced graphene oxide/Ni nanoparticle for lithium-sulfur battery cathode

Hierarchically structured carbon architecture is considered as a promising candidate of lithium-sulfur battery cathodes owing to its large surface area and percolated electron/ion pathways. However, the synthesis of hierarchical carbonaceous materials requires complicated processes and the resulting materials usually provide weak physical interactions to capture lithium polysulfides, which significantly hinders the performance of lithium-sulfur batteries. In order to resolve these problems, we have demonstrated a facile microwave-assisted synthesis of carbon nanotubes branches grown onto steam-activated reduced graphene oxide (sGNC) to simultaneously synthesize hierarchical carbon structure and nickel nanoparticles for the inhibition of lithium polysulfides shuttle. The hierarchical structure of carbon nanotubes branched from anchored nickel nanoparticle seeds, and uniform distribution of sulfur is attributed to the facilitated electron/ion diffusion pathway, sufficient space to impregnate sulfur, and the lithium polysulfides capturing sites. Accordingly, sGNC-sulfur (sGNC-S) cathode achieved the initial discharge capacity of 829.3 mAh g − 1 at 0.5 C, which is much higher than 531.8 mAh g − 1 of steam-activated reduced graphene oxide-sulfur (sG-S) cathode. When the current rates increased from 0.1 C to 1 C, the capacity retention of the sGNC-S cathode was 67.0%, greater than 62.5% of the sG-S cathode. The decay rate of 0.155%/cycle with the Coulombic efficiency of almost 100% over 200 cycles of the sGNC-S cathode was greater than 0.219%/cycle of the sG-S cathode, originating from facile kinetics and restricted polysulfide dissolution.

Negative phototaxis of jumping cocooned parasitoid wasp larvae against short wavelengths and physicochemical properties of the cocoon shell

The parasitoid wasp Bathyplectes anurus (Hymenoptera: Ichneumonidae: Campopleginae) is a successful biocontrol agent against the alfalfa weevil, Hypera postica. This weevil is a serious pest of beneficial fabaceous plants such as alfalfa and Chinese milk vetch. One of the possible reasons for the success of this wasp in hot climates may be the ability of its cocooned larvae to repeatedly jump and roll until they relocate themselves away from detrimental sunlight and heat. It is not yet known which wavelengths of light trigger this avoidance behavior or the microstructure of the cocoon shell that might allow light transmission. Here, the response of the cocooned larvae to different wavelengths, and the microstructure, hardness, and elemental components of the cocoon shell were studied. A population of cocooned larvae were introduced on the boundary line between illuminated and shaded areas with blue, green, red, or near-infrared light-emitting diodes. The cocoons moved away from the blue and green light. The distance from the boundary to the cocoons in the shaded area was longer under these long wavelengths, followed by the red light and shortest under the near-infrared light and nil under darkness. No difference was found in mortality between different wavelengths after three days of illumination. Scanning electron microscope observations of the surface of the cocoon shell revealed that the belt-like central ridge was porous, which likely allows ventilation and light transmission. The surface of the cocoon shell showed a uniform distribution of sulfur, potentially aiding in the capture of green wavelengths. The ridge had twice the thickness of the main body and was 1.9 times harder than the main body. These results may be applied to better understand the individual responses of this biological control agent to modifications to their environment, including light pollution.

Sulfur polymerization strategy based on the intrinsic properties of polymers for advanced binder‐free and high‐sulfur‐content Li–S batteries

AbstractLithium–sulfur (Li–S) batteries are the promising next‐generation secondary energy storage systems, because of their advantages of high energy density and environmental friendliness. Among numerous cathode materials, organosulfur polymer materials have received extensive attentions because of their controllable structure and uniform sulfur distribution. However, the sulfur content of most organosulfur polymer cathodes is limited (S content <60%) due to the addition of large amounts of conductive agents and binders, which adversely affects the energy density of Li–S batteries. Herein, a hyperbranched sulfur‐rich polymer based on modified polyethyleneimine (Ath‐PEI) named carbon nanotube‐entangled poly (allyl‐terminated hyperbranched ethyleneimine‐random‐sulfur) (CNT/Ath‐PEI@S) was prepared by sulfur polymerization and used as a Li–S battery cathode. The high intrinsic viscosity of Ath‐PEI provided considerable adhesion and avoided the addition of PVDF binder, thereby increasing the sulfur content of cathodes to 75%. Moreover, considering the uniform distribution of elemental sulfur by the polymer, the utilization of sulfur was successfully improved, thus improving the rate capability and discharge capacity of the battery. The binder‐free, sulfur‐rich polymer cathode exhibited ultra‐high initial discharge capacity (1520.7 mAh g−1 at 0.1 C), and high rate capability (804 mAh g−1 at 2.0 C). And cell‐level calculations show that the electrode exhibits an initial capacity of 942.3 mAh g−1electrode, which is much higher than those of conventional sulfur‐polymer electrodes reported in the literature.

Design and synthesis of novel pomegranate-like TiN@MXene microspheres as efficient sulfur hosts for advanced lithium sulfur batteries.

Lithium-sulfur (Li-S) batteries have the characteristics of low cost, environmental protection, and high theoretical energy density, and have broad application prospects in the new generation of electronic products. However, there are some problems that seriously hinder the Li-S batteries from going from the laboratory to the factory, such as poor stability caused by the large volume expansion of sulfur during charging and discharging, sluggish kinetics of the electrochemical reaction resulting from the low conductivity of the active materials, and loss of active materials arising from the dissolution and diffusion of the intermediate product lithium polysulfides (LiPSs). In this paper, the two-dimensional layered material MXene and TiN are firstly combined by spray drying method to prepare pomegranate-like TiN@MXene microspheres with both adsorption capacity and catalytic effect on LiPSs conversion. The interconnected skeleton composed of MXene not only solves the problem of easy stacking of MXene sheets but also ensures the uniform distribution of sulfur. Without affecting the excellent characteristics of MXene itself, the overall conductivity of the composite electrode material is improved. The TiN hollow nanospheres are coated with MXene layers to form a shell, catalyzing the adsorption of LiPSs and accelerating the transformation of high-order LiPSs to Li2S2/Li2S. As a result, the TiN@MXene cathode delivers a high initial discharge capacity of 1436 mA h g-1 at 0.1C, excellent rate performance of 636 mA h g-1 up to 3C, and an ultralong lifespan over 1000 cycles with a small capacity decay of 0.048% per cycle at the current density of 1.0C.

Supercritical carbon dioxide assisted synthesis of ultra-stable sulfur/carbon composite cathodes for Li– S batteries

To mitigate the shuttle effect and enhance the electrical conductivity in lithium battery cathode, the unique characteristics of supercritical CO2 solvent (SC–CO2) and the distinctive porous and layered microstructure of reduced graphene oxide (rGO) are exploited in the fabrication of a high-performance rGO/sulfur composite cathode. Exploiting SC-CO2 technology can realize highly efficient sulfur transfer and precise microstructure regulation of S/C composite cathodes for Li–S batteries. On exposure, due to the sudden pressure release process, the SC-CO2 expands the interlayers of rGO rendering plenty of storage space for small sulfur allotropes in carbon matrices which increases the active sulfur loading. Being a remarkable hydrophobic solvent, the wetting properties of SC-CO2 are excellent, ensuring sulfur dissolution and penetration deep into the voids and interlayers of rGO. This creates intimate contact of sulfur with rGO interlayers, guaranteeing precise sulfur content, uniform sulfur distribution, and strong interaction between sulfur and carbon leading to enhanced electrical conductivity and sulfur utilization efficiency. Another important feature is that the S/C composites can be prepared at room temperature, unlike other conventional techniques which require a higher temperature. Moreover, the product mixture can be separated simply by de-pressuring SC-CO2. Herein, the rGO/sulfur composite cathode prepared on a lab scale showed an initial discharge capacity of 1024 mAh/g at 0.1C rate with capacity retention of 92.2% and coulombic efficiency of 99% even after 200 charge-discharge cycles. The developed cells showed excellent performance (929 mAh/g at 1 C rate) with an ultralow decay of 0.04% per cycle even after 200 charge-discharge cycles. Through this work, we believe that the synergistic effect of SC-CO2 technology and rGO as sulfur host will open up a promising future for the synthesis of efficient S/C composite cathodes with ultra-high cycling stability.

Creating Edge Sites within the 2D Metal‐Organic Framework Boosts Redox Kinetics in Lithium–Sulfur Batteries

AbstractLithium–sulfur batteries have received extensive interest owing to their exceptionally high energy density. Nonetheless, their practical implementation is still impeded by the shuttle effect of polysulfides and sluggish conversion kinetics. Considering that, a porous 2D defective zeolitic imidazolate framework‐7 (ZIF‐7) with abundant active edges is rationally designed as multifunctional sulfur carriers for Li–S batteries. The 2D ZIF‐7 enables uniform distribution of sulfur and rapid Li‐ion diffusion, while rich edges facilitate sufficient exposure to active sites capturing and catalyzing polysulfides. In addition, the nitrogen defects on edge sites can further accelerate the transformation of polysulfides and decrease the energy barrier of Li2S decomposition. Consequently, the Li–S batteries demonstrate surprisingly practical prospects with a stable capacity of 676.9 mAh g−1 over 500 cycles at 1 C (capacity retention rate = 72.3%). When assembled into a pouch cell at 2.3 mg cm−2, it still exhibits a high capacity of 901.1 mAh g−1 after 100 cycles at 0.1 C. This work offers a rational structural design strategy to tackle the challenges of the sulfur cathode.

Facile Dissolution-Crystallization Strategy to Achieve Rapid and Uniform Distribution of Sulfur on Porous Carbon for Lithium-Sulfur Batteries.

In this work, we proposed a facile dissolution–crystallization strategy based on density functional theory calculations to achieve rapid as well as uniform distribution of sulfur on porous carbon. Sulfur-containing solution can completely penetrate porous material and in preference remove into the pores under the influence of capillary force, and sulfur tends to crystallize on the defective even non-defective carbon matrix rather than agglomerate. The S/PC composites prepared by this method can still achieve uniform distribution of sulfur when the sulfur content is as high as 85%. All operations can be completed within a few minutes without any heating. Compared with common melt-diffusion and vapor-phase infusion, this approach has lower energy consumption and is simple, safe, continuous, and rapid.

Graphene-wrapped microspheres decorated with nanoparticles as efficient cathode material for lithium-sulfur battery

• Graphene-wrapped microspheres decorated with metal nanoparticles was developed. • Cr-Ni-NDs@G is an efficient multifunctional sulfur host material for Li-S batteries. • The interaction and conversion kinetic of lithium polysulfide were studied. • The sulfur cathode exhibits high specific capacity and cycling performance. Lithium-sulfur (Li-S) battery is now a promising technology for energy storage. However, the commercialization of Li-S battery was hindered by the shuttle effect of lithium polysulfide and the slow reaction kinetics of sulfur. In this study, MIL-101(Cr) with graphene oxide was composited together through spray-drying. Then, a graphene microsphere composite consisted of three-dimensional conductive network decorated with Cr-Ni-based nanodots (Cr-Ni-NDs) was developed through a facile heat treatment. The microsphere composite was denoted as Cr-Ni-NDs@G, which offers a porous structure and high surface area to increase the accommodation and uniform distribution of sulfur in the cathode. Meanwhile, the three-dimensional conductive network embedded by Cr and Ni nanoparticle not only improved the transportation of electrons, but also act as the active site strengthening the adsorption of lithium polysulfide, promoting the catalytic transformation of lithium polysulfide to Li 2 S. Due to these complementary features, the S/Cr-Ni-NDs@G cathode exhibited a high initial specific capacity (1222.3 mAh·g −1 at 0.2C) and good rate performance (706 mAh·g −1 at 3.0C). In addition, after 500cycles at 1.0C, the faded rate of per cycle of the Li-S battery is only 0.059%. The result demonstrated that S/Cr-Ni-NDs@G composite can be a promising energy storage material in the development of Li-S batteries.

Hierarchically Porous Ti3C2 MXene with Tunable Active Edges and Unsaturated Coordination Bonds for Superior Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries hold great promise for next-generation electronics owing to their high theoretical energy density, low cost, and eco-friendliness. Nevertheless, the practical implementation of Li-S batteries is hindered by the shuttle effect and sluggish reaction kinetics of polysulfides. Herein, the spray drying and chemical etching strategies are implemented to fabricate hierarchically porous MXene microspheres as a multifunctional sulfur electrocatalyst. The interconnected skeleton offers uniform sulfur distribution and prevents the restacking of MXene sheets, while the abundant edges endow the nanosheet-like Ti3C2 with rich active sites and regulated a d-band center of Ti atoms, leading to strong lithium polysulfide (LiPS) adsorption. The unsaturated Ti on edge sites can further act as multifunctional sites for chemically anchoring LiPS and lowering Li-ion migration barriers, accelerating LiPS conversion. Owing to these structural advantages, excellent cycling and rate performances of the sulfur cathode can be obtained, even under a raised sulfur loading and lean electrolyte content.

Three-Dimensional Engineering of Sulfur/MnO2 Composites for High-Rate Lithium-Sulfur Batteries.

Herein, a three-dimensional interconnected sulfur (3DIS) system is used to construct a cathode of the lithium-sulfur battery. Compared with the traditional methods of encapsulating sulfur, the 3DIS system serves as a framework to grow MnO2, which ensures a high sulfur content of 91.5 wt % (the ratio of sulfur/host was 10.8) and a uniform distribution of sulfur. Due to the synergistic effect of the 3D interconnected architecture and the uniform coating layer of polar MnO2, 3DIS@MnO2 (3DISMO) delivers a capacity of 891 mA h g-1 after 900 cycles at 1 C. Even at a rate of 10 C, a capacity decay rate of 0.061% per cycle is achieved.

Macroporous Multichannel Carbon Nanofibers Embedded with Co/Fe‐N Electrocatalyst as the Sulfur Host for Boosting Polysulfides Conversion in Lithium‐Sulfur Batteries

AbstractLithium‐sulfur batteries (LSBs) are widely recognized as promising candidates for next‐generation energy storage systems, yet suffering from sluggish redox kinetics and severe shuttle effect. Herein, the macroporous multichannel carbon nanofibers (MCFs) embedded with Co/Fe−N active sites (Co/Fe−N/MCFs) were prepared by electrospinning and functionalized as the sulfur host for LSBs. The opening macropores in MCFs facilitate the storage and uniform distribution of sulfur. Meanwhile, the built‐in Co/Fe−N sites possess double‐end binding sites toward polysulfides (LiPSs), which provides an effective way for immobilization and catalytic conversion of LiPSs. The designed sulfur host with good electrical conductivity and high catalytic activity enables fast kinetics of sulfur redox reaction and reduces cell polarization. As a result, the cell equipped with the Co/Fe−N/MCFs/S cathode shows an initial capacity of 1523 mA h g−1 at 0.2 C and an ultrahigh rate performance of 891 mA h g−1 at 5 C, and a low decay of 0.051 % per cycle over 1000 cycles at 1 C. This work will enlighten the rational design of advanced sulfur host for practical application of LSBs.

Controlled Synthesis of Porous Carbon Nanostructures with Tunable Closed Mesopores via a Silica-Assisted Coassembly Strategy

Controllable fabrication of mesoporous carbon nanoparticles (MCNs) with tunable pore structures is of great interest, due to the remarkable effect of pore structure on electrochemical performance o...

A Li-S battery with ultrahigh cycling stability and enhanced rate capability based on novel ZnO yolk-shell sulfur host

Shuttle effect is still a challenging issue for Li-S batteries. Here, we synthesize the yolk-shell ZnO structure as sulfur host, which effectively suppresses lithium polysulfides shuttling effect and enhances the electrochemical performance of Li-S batteries. Currently, lithium-sulfur (Li-S) batteries still suffer from fast capacity decay, poor coulombic efficiency (CE) and short cycling lifespan, which result from the severe shuttle effect issue caused by high solubility and rapid diffusion of lithium polysulfides (LiPSs) in organic electrolytes. Here, yolk-shell zinc oxide (YS-ZnO) spheres are synthesized and for the first time, applied as a host for Li-S batteries to tackle this challenge. The polar ZnO exhibits high chemical anchoring ability toward LiPSs while the unique yolk-shell structure not only provides an additional physical barrier to LiPSs but also enables much more uniform sulfur distribution, thus significantly suppressing LiPSs shuttling effect meanwhile promoting sulfur conversion reactions. As a result, the YS-ZnO enables the Li-S battery to display an initial specific capacity of 1355 mAh g −1 and an outstanding capacity retention capability (~89.44% retention rate) even after 500 cycles with the average CE of ~99.46% at the current of 0.5 C. By contrast, the capacity of conventional-ZnO-nanoparticles based battery severely decays to 472 mAh g −1 after cycling for 500 times. More impressively, the S/YS-ZnO based Li-S battery can maintain a low decay rate of 0.040% every cycle and high average CE of 98.82% over 1000 cycles at 3 C.

Reducing the shuttle effect with the interactions of polar TiN and non-polar graphene for lithium–sulfur batteries

Chemical anchoring and facilitated transformation of polysulfides by polar titanium nitride nanoparticles and uniform distribution of sulfur by non-polar graphene showed efficient cooperative interactions for lithium–sulfur batteries.

Electrochemical behaviors of graphene decorated sulfurized polyurethane foam-based ultra-microporous carbon

Polyurethane foam is a typical commercial polymer with a large production quantity and its waste needs to be recycled. This work reports a facile method to prepare ultra-microporous carbon from the polyurethane foam (PUF) waste and use it as a reservoir to impregnate sulfur for Li-S batteries. The raw PUF was carbonized and then activated with KOH. By controlling the activation temperatures, four carbon materials (PUFC-T) with different textures and N-doping levels were obtained. PUFC-800 shows the highest BET surface area, microporous volume, and quaternary N and pyridine N-oxide species. The electrochemical test results showed that higher microporous volume is beneficial to increase the uniform distribution of sulfur, as a result, the cycle stability and rate capacity is improved significantly. A large reversible capacity of 542 mAh g-1 can be retained at a large current of 0.5 C after 200 cycles with high sulfur loading of 70%.