| In the new century. Chemical power sources more closely related to energy, facing a growing energy crisis and how to study sustainable clean energy as today’s society one of the most talked about topics. Lithium-ion batteries because of its high energy density and superior performance characteristics, has been widespread concern in recent years. In a wide range of lithium batteries, lithium-sulfur batteries as specific energy and volume than the solid electrode materials of highest energy system, so popular around the world, and as a next-generation lithium-ion battery development direction. However, due to poor conductivity of sulfur cathode in lithium-sulphur batteries, volume expansion, intermediate States of sulfur ion shuttle problems, and lithium metal anode used for cell security is also a big risk, so lithium-sulphur battery is still in the laboratory stage. Therefore, from the perspective of improvement of sulfur-containing cathode to cathode materials prepared, carried out the following work:First, the vulcanization accelerator(2-Mercapto benzo thiazole) to build S-PAN(PAN-S) of composites containing sulphur. Experiment 2-Mercapto benzo thiazole in PAN and sulfur acts as a vulcanization accelerator in high temperature reaction processes, for the curing of polyacrylonitrile provide more responsive site, thereby upgrading the sulfur cathode materials. Characterization and test data show that using this cathode material for vulcanization Accelerator can make increase the sulphur content of around 8%, corresponds to 120mAh/g capacity to enhance(based on the entire electrode material), containing cathode material for vulcanization accelerator in the first volume for 628mAh/g(based on the entire electrode material), in after 200 cycles, equivalent to the second volume of no significant attenuation.Second, based on the work of the first part, we continue to enhance the sulphur of PAN-S composite, but the direct consequences of the higher sulphur is the long chain sulphur and incompatibilities of the electrolyte, so we modified cathode materials by using the electrolyte additives to avoid too much contact of the electrodes and electrolyte, thus improving battery performance. Characterization and test data shows that compared with does not contain additives for electrolyte, battery shows good cycling stability of the additive.Third, to solution Exchange legal prepared out containing nitrogen carbon material(NRC) package of Super fine of sulfide lithium nano particles, experiment in the using sulfide lithium in ethanol in the of solubility is greater than its in 2-methyl n-ketone in the of solubility this a characteristics, through volatile solvent to preparation polymer package of about 5nm of nano sulfide lithium particles, then high temperature carbide preparation out containing nitrogen carbon material package of nano sulfide lithium composite. Magnification of the material at 0.25 C after1000 cycles, each attenuation capacity of only 0.046%.In this paper, PAN-S and Nano Li2S@NRC materials were designed and synthesized various composite materials, from its design, synthesis of these two directions were discussed, and the physical and chemical properties were characterized. By assembling it into a button battery, using electrochemical impedance spectroscopy, cyclic voltammetry and cycling test of electrochemical test material properties were evaluated. Results show that these strategies in different extent, improve the performance of lithium-sulfur batteries for later preparation of lithium-sulfur batteries provide a good reference. |
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