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The honeycomb-like hierarchical porous carbon nanofibers (PCNFs)-carbon nanotubes (CNTs)-sulfur(S) composite electrode is successfully desgined and prepared through ball-milling and heating method, in which the PCNFs are carbonized from fibers in the membrane composed of Polyvinyl Alcohol and Polytetrafluoroethylene by electro-blown spinning technology. The prepared PCNFs-CNTs-S composite are regarded as cathode for lithium-sulfur battery. The tailored porous structure and CNTs in the composite facilitate construction of a high electrical conductive pathway and store more S/polysulfides, and the dissoluble loss of intermediate S species in electrolyte can also be restrained because of acidized PVA-based porous carbon nanofibers. Meanwhile, the porous strcucture and CNTs can effectively alleviate volume changes in battery cycling process. Moreover, the presence of LiNO 3 in electrolyte helps the electrochemical oxidation of Li 2 S and LiNO 3 -derived surface film effectively suppresses the migration of soluble polysulfide to the Li anode surface. Therefore, the obtained PCNFs-CNTs-S cathode exhibits excellent performance in Li-S battery with a high initial discharge capacity as high as 1302.9 mAh g −1 , and super stable capacity retention with 809.1 mAh g −1 after 300 cycles at the current density of 837.5 mA g −1 (0.5 C). And the rate capability of PCNFs-CNTs-S electrode is much better than those of CNTs-S and PCNFs-S electrodes. [ABSTRACT FROM AUTHOR]

Lithium-sulfur batteries have been considered as one of the most promising energy storage candidates due to their high energy density and low cost. However, the low electrical conductivity of elemental sulfur, notorious LiPS shuttle and sluggish redox kinetics bring about fast capacity fade and poor rate capabilities. To solve these problems, herein a modification strategy of functional separator is introduced by coating heterostructured MoP–MoS 2 and porous carbon nanofibers (PCNFs) on the surface of a Celgard separator. Moreover, for the first time, we detailly discuss the effect of the ratio of component (MoP:MoS 2) in the heterostructured MoP–MoS 2 materials on the electrochemical performance. The coating layer exhibits both satisfactory interception ability for LiPS shuttle and fast LiPS conversion ability due to abundant anchoring sites of MoP–MoS 2 heterojunction nanoflowers and shortened lithium ion channel of the prepared PCNFs. Benefiting from these advantages, the assembled Li–S battery with a MoP-50/PCNFs separator exhibits 1090.02 mAh g-1, and high discharge capacity of 884.67 mAh g-1 even after 300 cycles at 1 C. The initial discharge capacity of MoP-50/PCNFs separator at 2 C and 5 C are about 1050.4 and 728.22 mAh g-1, and retains about 698.4 mAh g-1 after 400 cycles and 431.28 mAh g-1 after 500 cycles. The novel work will provide a new strategy by which the modified separator with transition metal phosphides can be applied in the design of high-performance Li–S batteries and shows great potential for practical application. MoP-x/PCNFs modified Celgard separator in Lithium-sulfur battery. [Display omitted] • Preparing Flower-like heterostructured MoP–MoS 2. • Designing various heterostructured MoP–MoS 2 materials (MoP: MoS 2 = 100:0, 75:25, 50:50, 25:75, 0:100). • Porous carbon nanofiber with dual functions of lithium polysulfudes adsorption through one-step electrostatic blowing method. • Researching the catalytic kinetic mechanism of the "solid-liquid-solid" mutual conversion process for transition metal phosphide. • Exploring the cycle performance of Celgard separator modified with MoP–MoS 2 -50/PCNFs. [ABSTRACT FROM AUTHOR]

Lithium-sulfur batteries have been considered as one of the most promising energy storage candidates due to their high energy density and low cost. However, the low electrical conductivity of elemental sulfur, notorious LiPS shuttle and sluggish redox kinetics bring about fast capacity fade and poor rate capabilities. To solve these problems, herein a modification strategy of functional separator is introduced by coating heterostructured MoP–MoS 2 and porous carbon nanofibers (PCNFs) on the surface of a Celgard separator. Moreover, for the first time, we detailly discuss the effect of the ratio of component (MoP:MoS 2) in the heterostructured MoP–MoS 2 materials on the electrochemical performance. The coating layer exhibits both satisfactory interception ability for LiPS shuttle and fast LiPS conversion ability due to abundant anchoring sites of MoP–MoS 2 heterojunction nanoflowers and shortened lithium ion channel of the prepared PCNFs. Benefiting from these advantages, the assembled Li–S battery with a MoP-50/PCNFs separator exhibits 1090.02 mAh g-1, and high discharge capacity of 884.67 mAh g-1 even after 300 cycles at 1 C. The initial discharge capacity of MoP-50/PCNFs separator at 2 C and 5 C are about 1050.4 and 728.22 mAh g-1, and retains about 698.4 mAh g-1 after 400 cycles and 431.28 mAh g-1 after 500 cycles. The novel work will provide a new strategy by which the modified separator with transition metal phosphides can be applied in the design of high-performance Li–S batteries and shows great potential for practical application. MoP-x/PCNFs modified Celgard separator in Lithium-sulfur battery. [Display omitted] • Preparing Flower-like heterostructured MoP–MoS 2. • Designing various heterostructured MoP–MoS 2 materials (MoP: MoS 2 = 100:0, 75:25, 50:50, 25:75, 0:100). • Porous carbon nanofiber with dual functions of lithium polysulfudes adsorption through one-step electrostatic blowing method. • Researching the catalytic kinetic mechanism of the "solid-liquid-solid" mutual conversion process for transition metal phosphide. • Exploring the cycle performance of Celgard separator modified with MoP–MoS 2 -50/PCNFs. [ABSTRACT FROM AUTHOR]

Lithium-sulfur battery is regarded as one of the promising next-generation energy storage to electrical and portable devices thanks to its extremely high theoretical capacity, energy density, good environmental protection and low cost. However, the practical application of lithium-sulfur battery is still greatly impeded by the low Coulombic efficiency and the short lifespan, which is mainly attributed to the polysulfide shuttle and the uncontrollable lithium dendrite growth. Suppressing the growth of the lithium dendrite and hindering the notorious reaction between soluble polysulfides and lithium are extremely critical not only to a safe and efficient lithium anode, but also to the high-capacity lithium-sulfur battery. A comprehensive review of various strategies for strengthening the anode stability of lithium-sulfur battery is presented in this paper, including modifying the electrolyte and current collector, employing artificial protection films and finding alternative anodes to replace the lithium anode. The effects of different selections and the resulting properties of the anodes on the overall lithium-sulfur battery performance are discussed. The current research challenges and future perspectives associated with lithium-sulfur battery anode are also discussed. [ABSTRACT FROM AUTHOR]

In this study, F-doped tree-like nanofiber structural poly-m-phenyleneisophthalamide (PMIA) membranes are prepared via one-step electrospinning approach and their application performance as separators for lithium-sulfur batteries are discussed. The F-doped PMIA membrane can be regarded as matrix to form gel polymer electrolyte. The F doping endows the PMIA membranes with extraordinary high electrolyte uptake, excellent ability of preserving the liquid electrolyte and forceful chemisorption to polysulfides. And the tree-like structure effectively blocks polysulfides by the physical confinement. The lithium-sulfur cell with the F-doped PMIA separator exhibits high first-cycle discharge capacity of 1222.5 mAh g −1 and excellent cycling stability with good capacity retention of 745.7 mAh g −1 and coulombic efficiency of 97.97% after 800 cycles. The remarkable performance can be ascribed to the suppressed shuttle effects through both the physical trapping of polysulfides by the gel polymer electrolyte based on matrix with F-doped PMIA membrane and the tree-like structure in a working cell. [ABSTRACT FROM AUTHOR]

Lithium-sulfur battery is considered as one of high performance batteries of the new generation owing to its extremely high theoretical capacity, energy density, good environmental protection and low cost. These features make it of great significance to serve as the next-generation battery especially in electric vehicles and portable devices. However, the practical application of lithium-sulfur battery is still hindered due to some obstacles including the low electrical and ionic conductivity of elemental sulfur, the discharge product Li 2 S and the “shuttle effect” caused by the dissolved polysulfide species. In this review, the current trends, fundamental studies and developments for lithium-sulfur battery separators including some modified functional and novel battery separators with the customized structure designs are presented and reviewed. The effects of different selections and the resulting properties of the separators affecting the overall lithium-sulfur battery performances are discussed as well. The current research directions and challenges associated with the use of battery separator and the future perspectives for this class of the battery separator are concluded as well. [ABSTRACT FROM AUTHOR]