Preparation & Modified Of AAO Template To Fabricate Nanowire Arrays As The Cathode Material

Since lithium-sulfur battery have a promising theoretical volume and high power density, environmental friendly. Furthermore, sulfur is a kind of earth-abundant resource, thus, it has attract scientist's great attention. But sulfur used as cathode material have raised some serious problems: poor electrical conductivity, lost of active material which cause low utilization of sulfur, short cycle ability has blocked its industrial application. In this dissertation, we focus on fabricating 10-20 um anodic aluminum oxide(AAO) template by aluminum sheet(99.5%) at room temperature(30?) and combine with our research condition we advanced a new approach to reduce the barrier layer-Current Reduction Process. Then, used the modified AAO template to electrochemically polymerize the pyrrole and successfully prepared the polypyrrole nanowire conductor net and carbon nanotubes conductor net. Moreover, we fabricated the sulfur-lithium battery cathode by the polypyrrole nanowire conductor net and carbon nanotubes conductor net with sulfur composite hope to obtain a new sulfur-lithium battery system with high volume and power density.We investigated and fabricate the AAO template by two-anodic step at the condition of: H2C2 O as the electrolyte, aluminum sheet(99.5%), room temperature(30?). Scanned by field emission scanning electron microscope(FESEM) and found that annealing process under 500? is the key to attain the perfect AAO template. The mixed acid(1.8%H2Cr2O4+6%H3PO4 by weight) under 60?etch away the AAO at a speed of 0.71um/min. The 5%H3PO4(by weight) under 30? expanding the AAO nanopore at a speed of 1.47nm/min.For the sake of electrochemically polymerized polypyrrole and made carbon nanotubes by the AAO template directly we need to reduce the barrier layer. And then successfully advance the Current Reduction Process-work out the statistic of current-voltage at every equilibrium, then reduce the current step by step, since under room temperature it reaction to the state of equilibrium quickly, use the current as the indicator can shorten the barrier reduction process greatly. Compare with the chemical etching process and voltage reduction process, Current Reduction Process can maintain the structure of AAO and avoid “V” channel at the same time.Having modified the AAO template, we electrochemically synthesis the polypyrrole nanowire array and come out the conclusion that when we use the acetonitrile & lithium perchlorate as the electrolyte at the voltage of 0.7V could we synthesis the perfect polypyrrole nanowire array. And the result can be proved by FESEM and X-ray diffraction(XRD).At last we used the fabricated polypyrrole nanowire arrays and carbon nanotubes array mixed with sulfur composite as the cathode material to improve the electrochemical performance of Lithium-sulfur battery.