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|Title: ||硫化錫粉體作為鋰離子電池陽極活性材料的效能與穩定性研究;Synthesis and Characterization of SnS2 Anode Material for Li ion battery|
|Keywords: ||硫化錫;鋰離子電池;水熱法;溶劑熱法;Tin Sulfide;lithium-ion batteries;hydrothermal;solvothermal|
|Issue Date: ||2014-10-15 14:38:02 (UTC+8)|
|Abstract: ||本實驗中藉由水熱法以及溶劑熱法，改變反應溶劑製備出具有不同表面形貌之SnS2粉體，由乙二醇以及水所製備出的粉體均為奈米結構組成的聚集體，而使用乙醇所製備出的粉體是由厚度約60－70 nm的奈米盤所組成之3D層狀微米結構。相較於前面兩種粉末(乙二醇以及水) ，此種微米結構能有效舒緩鋰離子嵌入－嵌出過程中，所產生的巨大體積膨脹。於300 mA/g (0.47 C) 的定電流下，反覆充放電100圈後，仍可提供414 mAh/g的可逆電容量，其維持率約為76 %。|
使用乙醇做為反應溶劑，當反應溫度降至100 oC時，可有效的減少3D層狀結構之奈米盤的厚度，其厚度約為20－40 nm；不僅可以緩和鋰離子嵌入過程中所造成的體積膨脹且可降低內阻，改善在高速下的電化學性能；於300 mA/g (0.47 C) 的定電流下，反覆充放電100圈後，仍可提供460 mAh/g的可逆電容量，其維持率高達84 %以及在5000 mA/g (7.75 C) 的快充速度下，可提供285 mAh/g之可逆電容量。因此擁有3D層狀結構以及有效減少奈米盤的厚度，可有效提升SnS2之電化學性能。
;As energy storage devices, lithium-ion batteries are extremely important power sources for various portable electronic devices and electric vehicles in modern society. Tin sulfide (SnS2) is low-cost, low toxicity, and high capacities (theoretical capacity：645 mAh/g), it has become one of the most promising anode materials to replace the already commercialized graphite (theoretical capacity：372 mAh/g) in the next generation of lithium ion batteries, and has attracted intensive research interest. Unfortunately, the main drawback of this system stems from the poor conductivity and a drastic pulverization problem due to the large volume change during the lithiation/delithiation process, leading to a high level of irreversibility (i.e, low columbic efficiency) and poor cycle life.
In this study, the different surface morphology of SnS2 powders is prepared by a simple hydrothermal and solvothermal route with different solvents. The powders which use ethylene glycol and DI water as solvent are nanostructures composed of aggregates. However, the powder which uses ethanol as solvent shows many 3D flowerlike microspheres with diameter of 1－2 μm that are composed of hundreds of nanosheets with thicknesses of 60¬－70 nm. Compared to previous two powders, the 3D flowerlike microspheres with hundreds of nanosheets can alleviate the volume change during the lithiation/delithiation process. At a constant current of 300 mA/g (0.47 C) , the 3D flowerlike microspheres exhibit reversible capacity of 414 mAh/g after 100 cycles with the retention of 76 %.
The powder which uses ethanol as solvent synthesized at 100 oC, can effectively reduce thickness of nanosheets with 20－40 nm. It not only can alleviate the volume change during the lithiation/delithiation process but also reduce the internal resistance, improving the electrochemical performance at high C-rate. At a constant current of 300 mA/g (0.47 C) , it exhibits reversible capacity of 460 mAh/g after 100 cycles with the retention of 84 %.And at a high constant current of 5000 mA/g (7.75 C) , it can provide the reversible capacity of 285 mAh/g. Therefore, both of the 3D flowerlike microspheres structure and a decrease of thickness can improve the electrochemical performance.
|Appears in Collections:||[化學工程與材料工程研究所] 博碩士論文|
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