溶劑熱法合成三硫化二銻複合材料應用於鈉離子電池負極

Solvothermal Synthesis of Sb2S3-C-graphene composite as Anodes for Sodium-ion Batteries

李承陽(Cheng-yang Li)

指導教授 ： 張仍奎

國立中央大學/工學院/材料科學與工程研究所/碩士(2015年)

摘要

本實驗以溶劑熱法製備三硫化二銻(Sb2S3)粉體，粉體為微米棒結構的聚集體，其直徑約為200~300 nm及長度約為3~5 μm的斜方晶系。後續將Sb2S3同時添加有機碳源-葡萄糖及碳材-石墨烯能夠有效提升電化學性質表現。數據顯示Sb2S3及同時添加葡萄糖和石墨烯的複合材料在20 mAg-1低速電流密度下可逆電容值為439 mAhg-1及605 mAhg-1；另一方面在100 mAg-1的定電流下，反覆充放電50圈後，可提供18%及43%的循環維持率，表示同時添加葡萄糖和石墨烯作為複合材料不僅可以緩和鈉離子嵌入及嵌出過程中所造成的體積膨脹，並藉由石墨烯增加粒子與粒子之間的導電率以優化在高速下的電化學性能，使其提供優良的循環穩定性。
後續研究進一步探討PC及EC/DEC(50/50 v/v)兩種有機電解液並加入FEC添加劑測試對電性的影響。另一方面也選用離子液體模擬室溫和高溫下對電化學性質的影響，在20 mAg-1低速電流密度下可逆電容值各為588 mAhg-1、734 mAhg-1；在100 mAg-1的定電流下各為207 mAhg-1、279 mAhg-1，反覆充放電50圈後，可提供55%及62%的循環維持率，表示高溫有助於降低離子液體黏滯度，提升離子遷移率。最後探討PVDF及Na CMC兩種黏著劑，由反覆充放電50圈後，可提供57%及70%的循環維持率，表示Na CMC具有良好的伸縮彈性，能夠有效抑制充放電時的體積膨脹變化。

關鍵字

鈉離子電池 ； 負極材料 ； 石墨烯 ； 三硫化二銻

並列摘要

In recent years, low-cost rechargeable batteries become more crucial for the development and application of large-scale energy storage system. Up to now, Li-ion battery is one of major energy storage devices, but it’s limited to the cost and resources. Recently, Na-ion battery has become one of the most promising energy storage system and considered to be a candidate device for the next generation .
In this study, Sb2S3 nanorods were solvothermally synthesized with/without glucose (carbon coating) and graphene as anode for sodium-ion battery. At a constant current of 20 mAg-1, pure Sb2S3 nanorods as anode exhibited a reversible capacity of 439 mAhg-1. On the other hand, the reversible capacity increased to 621 mAhg-1 while Sb2S3 nanorods as anode with glucose and graphene addition. Further studies on Ionic Liquid Electrolytes at different temperature for sodium-ion batteries, While at room temperature and high temperature , At a constant current of 100 mAg-1 after 50 cycles, show cycle retention are 55% and 62% .Finally, studies on different binder about PVDF and Na CMC, At a constant current of 100 mAg-1 after 30 cycles, show cycle retention are 57% and 70%.
In summary, as compare to pure Sb2S3, the capacity and cycle-life can be improved in the glucose-coated Sb2S3 which decorated on graphene as anode for Na-ion battery.Ionic Liquid Electrolytes can provide higher thermal stability than Organic Liquid Electrolytes and use binder with Na CMC can decrease volume change ,the reason is attribute to good elasticity.

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