Lithium‐sulfur battery as one of the most promising and attractive candidate among the emerging electrical energy storage has attracted enormous attentions. It has superior characteristics of high specific energy density (2600 Wh kg−1) and high theoretical specific capacity (1675 mAh g−1), which is equal to 3–5 times of lithium‐ion batteries, and more closed to the requirement of the pure electric vehicles and hybrid electric vehicles. Furthermore, sulfur element is inexpensive, naturally abundant, and environmentally friendly. However, the commercial application of lithium‐sulfur batteries (LSBs) still faces some major technical obstacles such as the low electrical conductivity of sulfur, the shuttle effect of polysulfides, and the drastic volume expansion during charge/discharge process. In this review paper, we focus on some of the effective strategies in boosting the electrochemical performance of LSBs through the development of sulfur/carbon composite electrode materials, including the use of porous carbons, carbon nanotubes/fibers, and graphene. The integration of carbon materials and sulfur can efficiently improve the utilization of active materials, enhance the conductivity of cathode materials, and provide a polysulfides barrier. Simultaneously, the challenges and prospects on LSBs in the near future are also presented and discussed.

A novel phosphazene-based compound called hexaphenoxycyclotriphosphazene (HPCTP) was synthesized and characterized by Fourier transform infrared spectroscopy as well as proton and phosphorus nuclear magnetic resonance spectroscopies. Epoxy (EP) resin composites containing HPCTP and octapropylglycidylether polyhedral oligomeric silsesquioxane (OGPOSS) were prepared using 4,4 0 -diamino diphenylmethane as curing agent. Differential scanning calorimetry, thermogravimetric analysis, UL 94 vertical burning test, and cone calorimetry test were used to assess thermal stability and flame retardancy of the composites. Evaluation of thermal properties demonstrated that the resulting composites achieved less thermal stability compared with control EP resin but possessed high char yields at high temperatures. It indicated that both HPCTP and OGPOSS could induce the formation of intumescent char layer that retarded the degradation and combustion process of EP resin. The peak heat release rate of EP resin composite containing 15 wt% HPCTP was 61% less than that of control EP resin. Meanwhile, other flame-retardant parameters were also improved. Results of scanning electron microscopy and energy-dispersive x-ray spectroscopy of residual chars confirmed that both HPCTP and OGPOSS can enhance thermal stability and flame retardancy of EP resin.

No abstract

Combining the advantages of the sol-gel method and solvothermal method, the single anatase phase of nano-titanium dioxide (TiO 2) with high crystallinity had been prepared by means of the sol-solvent thermal improved process, in which butyl titanate was used as titanium source; anhydrous ethanol as solvent; concentrated nitric acid as inhibitor; and cationic surfactant cetyl trimethyl ammonium bromide (CTAB), anionic surfactant sodium dodecyl benzene sulfonate (SDBS), and nonionic surfactant polyethylene glycol (PEG) as dispersants. The analysis results of Brunauer-Emmett-Teller, scanning electron microscopy, and transmission electron microscopy characterizations indicated that CTAB-modified TiO 2 with the optimum ratio had the most apparent dispersibility and the highest specific surface area compared with unmodified TiO 2 , SDBS-modified TiO 2 , and PEG-modified TiO 2. At the same time, the photocatalytic degradation rate of methyl orange could be improved to 99.16%. It indicated that the modification effect of CTAB was significantly better than those of SDBS and PEG, which made the nanoparticles uniformly dispersed, resulting in higher photocatalytic activity.

No abstract

No abstract

No abstract

No abstract