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Recently, Li-ion capacitor as a kind of novel energy storage device with high energy density and power density have caused wide concern. In this study, the porous carbon nanofiber/molybdenum disulfide nanoflake-flowerballs composite material is successfully prepared via hydrothermal method using the three-dimensional porous carbon nanofibers as a carrier. The molybdenum disulfide nanoflake-flowerballs are uniformly distributed and fill in three-dimensional porous carbon nanofibers skeleton, and the clear composite material with nanofiber morphology is formed. This material presents moderate specific surface area (81.67 m2 g−1) and good electrical conductivity (22.32 S cm−1) and is used as the anode in the Li-ion capacitor, and the big energy density at high power density (the energy density could reach 75.5 Wh kg−1 and 22.5 Wh kg−1 at power densities of 0.075 kW kg−1 at 30 kW kg−1, respectively) are achieved, which has broad application prospect in the energy storage field. • The three-dimensional PCNF loading MoS 2 nanoflake-flowerballs was constructed. • The MoS 2 nanoflake-flowerballs inner nanofibers provide the large reaction area. • The three-dimensional PCNF skeleton offers conductive path. • The 3D-PCNF/MoS 2 -NFFBs used as the anodes of LICs exhibit excellent properties. [ABSTRACT FROM AUTHOR]

Li-ion capacitor as a kind of new-style energy storage devices has attracted growing attention due to its high power and energy density. In this study, the stereoscopic honeycomb-like porous carbon nanofiber (PCNF) was used as a carrier of TiO 2 nanoparticles via simple immersion and calcination. The equally distributed anatase TiO 2 nanoparticles filling in the stereoscopic honeycomb-like PCNF skeleton provided large reaction sites, and the stereoscopic honeycomb-like PCNFs acting as support materials offered shorter electrical paths. The composite material presented unique fiber morphology, high specific surface area (268.32 m2g-1) and preferable electrical conductivity (1.31 S cm−1) which was used as an anode in Li-ion capacitor, and the large energy density versus power density (69.46 Wh kg−1 at 0.15 kW kg−1, 18.33 Wh kg−1 at 30 kW kg−1) and good cycle stability (retains 79.4% after 4000 cycles at 1 A g−1) were achieved, which had broad application prospect in the energy storage field. • A stereoscopic honeycomb-like PCNF loading TiO 2 nanoparticles material is designed. • The TiO 2 nanoparticles uniformly distribute and fill in stereoscopic carbon skeleton. • The stereoscopic honeycomb-like PCNF skeleton offers electrical conductivity to TiO 2. • The LIC with TiO 2 @PCNF anode exhibits good electrochemical properties. [ABSTRACT FROM AUTHOR]

In this work, the inorganic-organic nanofibrous composite separators were successfully prepared for Li-ion capacitor (LIC) via wet-laid method using electro-blown spun inorganic alumina (Al 2 O 3) nanofibers and electrospun organic polyimide (PI) nanofibers as components. Benefitting from the synergistic action of fast ions transfer performance and outstanding fire-resistance offered by Al 2 O 3 nanofibers as well as heat-resistance and entangled force derived from PI nanofibers, the novel membranes exhibited excellent film forming property, outstanding flexibility and high ionic conductivity. Moreover, it delivered superior fire-resistance with dimensional stability after burning. It was discovered that the novel membranes prepared with 50 wt% Al 2 O 3 nanofibers showed better ionic conductivity of 2.71 × 10−3 S cm−1 and broader electrochemical stability window of 5.3 V than those of commercial membranes. The LIC assembled with this novel separator reached the energy density of 12.5 Wh kg−1 even at the high power density of 15 kW kg−1. In addition, this LIC presented a high energy density of 57.3 Wh kg−1 at the current density of 0.5 A g−1 and maintained a high cycle stability even after 10,000 cycles. This study provided the design idea and experimental basis for the development of high-performance LIC separator. [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]

Solid polymer electrolytes replacing traditional liquid electrolytes are considered as an important strategy for developing lithium metal batteries with high safety and energy density. However, poor ionic conductivity and weak mechanical performances have greatly limited the development of solid polymer electrolytes. Here, we dispersed inorganic ceramic particles Li 6 · 4 La 3 Zr 1 · 4 Ta 0 · 6 O 12 (LLZTO) in the polyvinylidene fluoride (PVDF) electrospun nanofibers and then introduced them into polyethylene oxide (PEO) polymers to prepare composite electrolytes. The PVDF nanofibers with embedded LLZTO fillers can simultaneously reduce the crystallinity of the PEO polymer and provide a strong framework support for the composite electrolyte, thereby promoting the transmission of lithium ions and improving the lithium dendrite growth inhibition ability of the composite electrolyte. In addition, the uniform dispersion of garnet-type LLZTO active ceramic filler in the PVDF nanofiber membrane can further optimize the migration path of lithium ions. More importantly, the dehydrofluorination of PVDF due to the introduction of LLZTO can enhance the interaction among PVDF, LLZTO and lithium salts, which promotes dissociation of the lithium salt. The ionic conductivity of the composite electrolyte is as high as 9.30 × 10−4 S cm−1 at 50 °C, and the voltage of Li/Li symmetrical battery would not change significantly during 1200 h at 0.3 mA cm−2. Additionally, the composite electrolytes exhibit good electrochemical stability with the capacity retention rate of 96% under 1 C after 500 cycles. These results provide a strategy for the development of next-generation high-safety all-solid-state lithium metal batteries. An all-solid-state composite electrolyte is synthesized, which has superior ion transmission characteristics, mechanical strength and flexibility, bringing excellent long-cycle stability to Li/Li symmetric battery and Li/LiFePO 4 battery. Image 1 • An all-solid-state composite polymer electrolyte are successfully prepared. • Composite polymer electrolyte exhibits excellent mechanical strength and flexibility. • Li/Li batteries and Li/LiFePO 4 batteries assembled with the composite electrolytes have superior long-cycle stability. [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]