A new and feasible method to prepare long and well-oriented SWNTs on substrates in large scale is developed by applying a floating catalyst chemical vapor deposition (CVD) process. The catalysts for SWNT growth come from the decomposition of iron pentacarbonyl (Fe(CO)5) formed in situ from the reaction of iron powder and carbon monoxide gas. The growth of SWNTs is found to happen both on the substrate and in the gas flow. Both long and short nanotubes are formed on the substrates but only the long SWNTs are aligned by gas flow. The growth direction and the density of the long SWNTs can be easily controlled. In addition, long SWNTs can be cut and patterned using photolithography and water plasma etching techniques, offering a way to prepare patterned SWNTs with controllable orientation, density and lengths for various applications.

In order to improve the electrochemical performance of lead-acid batteries for energy storage, SnSO 4 and Sb 2 O 3 were selected as additives to form positive plates. The effects of these additives on the composition and the microstructure of the positive plate were investigated. The content of PbSO 4 and hydrated PbO 2 in positive active material (PAM) of lead acid batteries have been characterized by chemical analysis and X-ray photoelectron spectroscopy (XPS). Experiment results prove that the contents of hydrated PbO 2 gradually decrease with the increase of PbSO 4 , and the maximum depth-of-discharge (DoD) for electrodes is determined. Through contrastive analysis of different types of electrodes, the relation between the content of hydrated PbO 2 and cycle life has been obtained. Using this method, the cycle life of new batteries could be predicted rapidly.

In this study, we introduce a method to estimate the cycle life of lead–acid battery by analyzing the parameter of index of reaction depth.

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