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超細鉍奈米線的合成與機制探討
Thesis

超細鉍奈米線的合成與機制探討

高子倫
Masters, 國立清華大學, 化學工程學系
2012

Abstract

奈米線 合成 鋰離子電池 Bismuth Nanowires Synthesis Lithium-ion batteries(LIBs)
In this study, ultrathin bismuth nanowires(Bi UNWs) with an diameter of 2~4nm were synthesized in solution-phase system, and the mechanism was discussed. Oleylamine(OLA) played the role as solvent and formed polymer strands with the precursor of Bi (Bismuth 2-ethylhexanoate), then OLA reduced Bi3+ in situ to Bi0 with the existence of copolymer(PVP/HDE) as reaction inhibitor obtaining Bi UNWs. X-ray diffraction data showed that Bi UNWs are crystalline with rhomb-centered structure, and high-resolution transmission electron microscopy studies revealed that Bi UNWs grew along the [012] direction and frequently aggregated into bundle-like mesostructure, which is in accordance with X-ray diffraction data. Due to low melting point of Bi, Bi UNWs melted under electron beam irradiation, leading to the formation of small liquid droplets during TEM examination, and then re-crystallized to a polycrystalline nanowire. The experimental parameters, including method of mixing reagents, reaction temperature, amount of copolymer applied, surfactant, and reducing agent, were tuned to study their effects on the synthesis of Bi UNWs. Large scale synthetic experiment was carried out to evaluate the possibility of Bi UNWs for industrial scale production. Finally, Bi UNWs were also applied as the anode material for lithium-ion batteries. The higher the charge/discharge rate, the lower the capacity. Also, capacity fade is observed after a cycle life of 50 cycles.

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