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The anode performance of mesocarbon microbeads (MCMBs) is tested as they are used in sodium-ion batteries. The MCMBs carbonized at 700 °C consist of graphite-like crystallites with an interlayer distance of 357 pm, and with a crystal stack height of 1.61 nm. They deliver an initial charge capacity of 232 mAh g −1 at a current density of 25 mA g −1 , and keep a reversible capacity of 161 mAh g −1 after 60 cycles. The MCMB anodes exhibit good reversible sodium insertion/extraction behavior, which results from their internal crystallites and their unique external spherical surface layers. XRD and Raman analyses indicate that the MCMB anode stores energy by the electrochemical intercalation of sodium into the graphene sheets. [ABSTRACT FROM AUTHOR]

The synthesis of conductive composites consisting of waterborne polyurethane (WPU) and carbon black (CB) is reported. Besides the low percolation threshold (0.7–0.95 wt%), the composites are quite sensitive to organic solvent vapors regardless of their polarities as characterized by the drastic changes in conductivity. In the case of polar solvents, negative and positive vapor coefficient phenomena of the composites were successively observed with a rise in CB content. It was found that different mechanisms are responsible for the broad applicability of the composites as candidates for gas sensing materials owing to the different interactions among the matrix polymer, the filler particles and the solvent molecules. [Copyright &y& Elsevier]