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To improve the performance of lithium-ion batteries, the functional separators were developed by coating water-based polyvinylidene fluoride (PVDF) powder particles solution using polyvinyl alcohol as the binder on both sides of a conventional polypropylene (PP) microporous membrane by means of simple dipping. The electrochemical performance was tested and compared with that of pure PP membrane. It was found that the PVDF powder particles accumulated and scattered on the surface of PP membrane. Many voids existed among the powder particles. The thermal shrinkage percent tested at 130 °C for 1 h was decreased from 59.4% to 12.7%, whereas the electrolyte uptake was increased from 80% to 140%. The separator coated with 10% solid content of PVDF particles exhibited the best electrochemical performance, including the cycling performance and rate capability. The coated PVDF component not only decreased the interface resistance but also increased the ionic conductivity, owing to the high strong affinity of PVDF toward polar solvents and the voids among the PVDF particles to afford the passage for Li-ions. [ABSTRACT FROM AUTHOR]

In this paper, a stellated carbon filler (S-filler) through passivation of the surfaces of carbon nanotubes and carbon black (CNTs/CB) was fabricated, and the corresponding thermal conductive composites of polypropylene (blended with alumina) (PP/Al 2 O 3 ) incorporated with S-filler were fabricated. When adding 15 wt% S-filler, the composite shows an DC electrical resistivity as high as 8.34 × 10 11 Ω cm and high thermal conductivity about 0.68 W/m·k. The composite using the new carbon filler as hybrid part shows a higher thermal conductivity and electric insulation. The rheological test also shows that the percolation network is not formed by the S-filler. This work offers a novel route for the design of thermally conductive, but electrically insulative composites with polymer as a matrix. [ABSTRACT FROM AUTHOR]