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Sulfur composite material with a highly porous carbon sphere as the conducting container was prepared. The highly porous carbon sphere was easily synthesized with resorcinol-formaldehyde precursor as the carbon source. The morphology of the carbon was observed with field emission scanning electron microscope and transmission electron microscope, which showed a well-defined spherical shape. Brunauer-Emmett-Teller analysis indicated that it possesses a high specific surface area of 1563m2g-1 and a total pore volume of 2.66cm3g-1 with a bimodal pore size distribution, which allow high sulfur loading and easy transportation of lithium ions. Sulfur carbon composites with varied sulfur contents were prepared by melt-diffusion method and lithium sulfur cells with the sulfur composites showed improved cyclablity and long-term cycle life. [ABSTRACT FROM AUTHOR]

Sulfur composite was prepared by encapsulating sulfur into CMK-3 mesoporous carbon with different heating times and then used as the cathode material for lithium sulfur batteries. Thermal treatment at 300°C plays an important role in the sulfur encapsulation process. With 20h of heating time, a portion of sulfur remained on the surface of carbon, whereas with 60h of heating time, sulfur is confined deeply in the small pores of carbon that cannot be fully exploited in the redox reaction, thus causing low capacity. The S/CMK-3 composite with thermal treatment for 40h at 300°C contained 51.3wt.% sulfur and delivered a high initial capacity of 1375mAhg-1 at 0.1C. Moreover, it showed good capacity retention of 704mAhg-1 at 0.1C and 578mAhg-1 at 2C even after 100 cycles, which proves its potential as a cathode material for high capability lithium sulfur batteries. [ABSTRACT FROM AUTHOR]

Abstract: Magnesium doped Li1−2x Mg x FePO4/C (x =0.00, 0.01, 0.03, 0.05) cathode materials were synthesized by sol–gel method, and the effect of magnesium doping as well as its content on the electrochemical properties for lithium batteries was also investigated. Their morphology was studied with field emission scanning electron microscope and Li1−2x Mg x FePO4 materials showed the olivine phase without impurities. The thin carbon layer of Li1−2x Mg x FePO4/C was confirmed by high resolution transmission electron microscopy. The magnesium doped Li1−2x Mg x FePO4/C particles were smaller than those undoped. The Li1−2x Mg x FePO4/C materials showed better cycling behavior than undoped LiFePO4, especially at high C-rate in which Li0.94Mg0.03FePO4/C composition exhibited the best electrochemical properties. [Copyright &y& Elsevier]

Abstract: The synthesis, characterization and electrochemical properties of poly(vinylidene fluoride-co-hexafluoropropylene) {P(VdF-co-HFP)} prepared by electrospinning and phase inversion methods are reported. The morphologies of the membranes were studied by field emission scanning electron microscope and atomic force microscope. Thermal properties of the membranes were evaluated by differential scanning calorimetry. The resultant porous membranes are good absorbents of liquid electrolytes and exhibit high electrolyte retention capacity. The polymer electrolytes were prepared by soaking the membranes in liquid electrolyte. The temperature dependent ionic conductivity and electrochemical properties were evaluated. Li/LiFePO4 cell with electrospun membrane delivers a discharge capacity of 145mAh/g, which corresponds to 85% utilization of active material under the test conditions and shows lower capacity fade under continuous cycling. [Copyright &y& Elsevier]

In this work, we have developed a new cost-effective counter-electrode based on the Bi 2 S 3 /carbon nanofibers (Bi 2 S 3 /CNFs), which synthesized by combining the advantages of electrospinning technology and hydrothermal method. And by adjusting the concentration of Bi 2 S 3 , the Bi 2 S 3 nanoparticles were densely grown on the surface of carbon nanofibers without agglomeration. The dye-sensitized solar cells fabricated using Bi 2 S 3 /CNFs nanocomposite as counter electrode exhibit an overall power conversion efficiency of 7.64 % measured at 100 mWcm–2 illumination (AM 1.5 G), which is significantly higher than that of the most commonly used but expensive Pt counterpart (7.12 %). • Electrospun and hydrothermal techniques were used to synthesize the Bi 2 S 3 /carbon nanofibers (Bi 2 S 3 /CNFs). • A novel composite of Bi 2 S 3 /CNFs was first synthesized and used as counter electrode for DSSCs. • The DSSCs based on Bi 2 S 3 /CNFs CE achieved a PCE of 7.64%, which is significantly higher than Pt CE (7.12%). Dye-sensitized solar cells (DSSCs) counter electrode (CE) is needed to have both good electrical conductivity and high catalytic activity, and composite materials are better meet these two requirements. In this work, Bi 2 S 3 /carbon nanofiber (CNFs) composites are synthesized by simple electrospinning and hydrothermal methods, and after optimization of the content of Bi 2 S 3 , the large amount Bi 2 S 3 nanoparticles are grown densely on CNFs without agglomeration. Bi 2 S 3 /CNFs composites are first introduced into DSSCs as CE. The optimized Bi 2 S 3 /CNFs composites are of great electrochemical performance and obtain a photoelectric conversion efficiency (PCE) of 7.64 %, which is better than common used Pt CE (7.12 %). Thus Bi 2 S 3 /CNFs CE has great prospects based on low cost and simple fabrication process to develop Pt-free CEs which could accelerate the large-scale application of DSSCs. [ABSTRACT FROM AUTHOR]

• The Sb/PPy/CNT anode composite material with 3D structure was successfully prepared. • One-step preparation of Sb nanoparticles and in-situ growth of Sb/PPy/CNT composites. • The synthetic sample exhibits excellent potassium-storage performance. Antimony (Sb)-based materials are attractive as anodes in potassium ion batteries (PIBs). However, poor cycling and volume expansion of the Sb-based anodes hinder their development in PIBs. In this work, we prepared a novel three-dimensional Sb nanoparticle/polypyrrole/carbon nanotube (Sb/PPy/CNT) hybrid anode material. The obtained Sb/PPy/CNT maintained a discharge capacity of 555.1 mAh g−1 after 200 cycles at a current density of 100 mA g−1, and 347.5 mAh g−1 after 600 cycles at a high current density of 1000 mA g−1, showing outstanding potassium storage capacity and cycling performance. This excellent performance was attributed to the array of electron transfer networks formed in the hydrogel network, as well as inhibition of the volume expansion exhibited by potassium ions during embedding/detachment of the CNTs and Sb nanoparticles arising from encapsulation by PPy films. This study provides a prerequisite for expanding the use of high-performance anode materials for PIBs. [Display omitted] [ABSTRACT FROM AUTHOR]

A new type of sulfur electrodes with the ability for polysulfide adsorption was prepared by incorporating silica nanoparticles (SN) or amine functionalized silica nanoparticles (AFSN). AFSN was synthesized by a simple and cost-effective method. The functionalization and surface morphology of silica were confirmed with Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM), respectively. Polysulfide adsorption studies were carried out using UV–vis spectrometer, which confirmed the excellent adsorption of polysulfides by AFSN. Interaction of polysulfides with SN or AFSN was studied using FTIR and FT-Raman spectroscopy. The effective polysulfide adsorption by SN and AFSN leads to good and stable cycle performance of lithium sulfur cells. The results show that the incorporation of SN or AFSN with sulfur is a promising method to prepare cathode material for lithium sulfur batteries. [ABSTRACT FROM AUTHOR]

Highlights: [•] c-Axis oriented Na0.68CoO2:Ag composite thin films with nanosized Ag particles well dispersed in the Na0.68CoO2 matrix have been fabricated. [•] The power factor of Na0.68CoO2/5wt.% Ag nanocomposite thin film is about 2 times higher than that of the Ag-free film. [•] Adding metallic nanoinclusions is a promising way to improve the thermoelectric performance of Na x CoO2 films. [Copyright &y& Elsevier]