| Since Sony Company made lithium ion batteries commercialization in 1990, lithium ion batteries have been paid much attention by worldwide researchers and companies due to the advanced electrochemical properties, and have been developed quickly in recent ten years. Despite considerable efforts to find other substituents, carbon still remains the only commercial anode for the battery due to its steady structure and good circular properties.Although Nano-alloy as anode for Li-ion battery has higher specific capacity compared with carbon, there are some serious drawbacks: the volume will be expanded significantly during the alloying combined with lithium (e.g. Sn and Li can be alloyed into Li44Sn whose volume is 4 times of original volume). During charge-discharge process, great stress can be produced and it is easily powdered, which shall seriously affectthe circular properties. Therefore, how to improve circular stability of nano-alloys becomes current problem that should be solved urgently. Utilizing the carbon's good circular properties, the alloy's circular properties would be improved by preparing the metal/carbon nano-composite.On the basis of the catalysis of Lewis acid e.g. SnCl4 to aromatic hydrocarbons, a series of Sn/C nano-composites was synthesized using a coal tar pitch and a heavy oil (heavy fraction of light diesel oil, LDOHF) as carbon sources and Lewis acids such as tributyltin chloride (TBTC, 99%) and SnCl4.5H2O CAR) as catalysts by thermal condensation, solvent extraction and carbonization. In addition, another type of Sn/C composites was also prepared by carbonization of the Sn-type ion exchange resin at different temperatures. The preparation process and the microstructures of the Sn/C nano-composites were characterized by polarized light microscopy (PLM), power X-ray diffraction (XRD), scanning electron microscopy (SEM), transition electron microscopy (TEM), thermogravimetric analysis (TGA) and nuclear magnetic resonance ('H-NMR and I3C-NMR). And the electrochemical properties as anode for Li-ion battery was assessed by charge-discharge measurement and cyclic voltammetry (CV), respectively. The relation between the structure and electrochemical property of Sn/C composites was also discussed briefly.In the TBTC/pitch system, it was found that TBTC can catalyze thermal condensation of pitch and make the PI content of condensation product increase gradually from 35.5wt% at zero addition to 60.3wt% at 25% TBTC addition. With the addition of TBTC, the morphologies of the products was converted gradually from the regular sphericity to irregular block. The product containing 10% TBTC and carbonized at 600 shows a good anode properties for Li-ion battery, whose charge and discharge capacity is 674mAh/g and 465mAh/g, respectively, and the efficiency of charge-discharge achieves 95% after the second cycle.In the TBTC/oil system, it was found that TBTC makes the polymerization yield increase gradually at first, and then decrease gradually, finally go to constant. The morphology of the sample was mainly irregular block. With the addition of TBTC from zero to 82%, the first discharge capacity increases gradually from 227 mAh/g to 311 mAh/g when the Sn/C composites were carbonized at 800, and with the temperature elevation of heat-treatment from 600 to 1000, the fist charge-discharge capacity drops down. The product carbonized at 600癈 has an obvious capacity loss phenomenon. But the sample carbonized at 800 is less in the capacity loss with lower addition content of TBTC and it has a good circular property. However, with the higher TBTC addition, the capacity loss and circular property become bad. The products with lower TBTC addition carbonized above 800 (eg. TBTCaddition from zero to 16%) have a good electrochemical property as anode for Li-ion battery, their charge-discharge capacity are all above 200mAh/g, and the efficiencies of the first charge-discharge are near 90%.In the SnC14/oil system, it was found that SnCU can catalyze the po...
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