a b s t r a c tSulfur deposited on a hollow polyaniline sphere was prepared through in situ synthesis and used to investigate the electrochemical properties of lithium/sulfur cells. The fabricated hPANIs@S composite presented an excellent reversible capacity of 601.9 mAh g À1 after 100 cycles at 170 mA g À1 . The capacity increased with the cycle increase, especially at high charge/discharge current. For example, the capacity had only approximate 270 mAh g À1 after initial 121th cycle at 510 mA g À1 , and the capacity steadily increased to 380 mAh g À1 after 180th cycle at similar current. These results indicated that cycle property improved compared with that of pure sulfur prepared through in situ synthesis under similar conditions. The enhanced cycle property of the hPANIs@S composite could be due to the homogeneous distribution of fine sulfur particles on the PANI surface, which stabilized the nanostructure of sulfur and enhanced its conductivity during charge/discharge cycles.
Perfluoroalkoxy (PFA) composites filled with different volume fractions of hollow glass microsphere (HGM) and HGM/PFA-HGM/HBO 3 -HGM/PFA sandwich layered composites were prepared by simple dry mixing and hot-pressing process. The dielectric frequency and temperature response characteristics, thermal expansion coefficient, and mechanical strength were investigated as a function of the loading fraction of HGM fillers. The obtained .6V f HGM/.4V f PFA composite demonstrates ultralow-k (ε r ∼ 1,63@1 MHz; 1.57@10 GHz) with lowdielectric loss (∼7.2 × 10 −4 @1 MHz; ∼1.73 × 10 −3 @10 GHz), water absorption of ∼1.21%, in-plane thermal expansion coefficient of 42 ppm/ • C, and temperature coefficient of dielectric permittivity (τ εr ) of ∼−92 ppm/ • C. The temperature stabilities of dimension and dielectric permittivity for the .6V f HGB/.4V f PFA composite could be substantially improved by forming .6V f HGM/.4V f PFA-.6V f HGM/.4V f HBO 3 -.6V f HGM/.4V f PFA sandwich-layered composite, which still maintained reasonable dielectric properties and mechanical rigidity with flexural strength of ∼8.1 MPa.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.