Graphene Nanotube Iron Hierarchical Nanostructure as Lithium Ion Battery Anode
實驗方法不是很復雜,但思路非常的不錯,通過微波激發(fā)誘導的方法將分散在乙腈中的膨脹氧化石墨片轉(zhuǎn)化成三維層階結(jié)構(gòu)(乙腈中加入了二茂(絡)鐵和偶氮甲酰胺),最終使得石墨片中長出樹枝狀的碳管。而鐵原子或鐵納米粒子分布在石墨烯片上或者碳管的端口。充放電過程中由鋰與氧化鐵之間的可逆反應決定(作者認為),鋰原子主要在石墨烯面上和碳管外表面吸附或解吸。雖然充放電平臺中的電壓比較低,但材料的單位容量卻很驚人。重要的是從其中借鑒一種思路。
Si-Hwa Lee,† Vadahanambi Sridhar,† Jung-Hwan Jung,†,‡ Kaliyappan Karthikeyan,§ Yun-Sung Lee,§Rahul Mukherjee,^ Nikhil Koratkar,^ and Il-Kwon Oh†,*
In this study, we report a novel route via microwave irradiation to synthesize a bio-inspired hierarchical graphene nanotubeiron three-dimensional nanostructure as an anode material in lithium-ion batteries. The nanostructure comprises vertically aligned carbon nanotubes grown directly on graphene sheets along with shorter branches of carbon nanotubes stemming out from both the graphene sheets and the vertically aligned carbon nanotubes. This bio-inspired hierarchical structure provides a threedimensional conductive network for efficient charge-transfer and prevents the agglomeration and restacking of the graphene sheets enabling Li-ions to have greater access to the electrode material. In addition, functional iron-oxide nanoparticles decorated within the three-dimensional hierarchical structure provides outstanding lithium storage characteristics, resulting in very high specific capacities. The anode material delivers a reversible capacity of ~1024 mA 3 h 3 g1 even after prolonged cycling along with a Coulombic efficiency in excess of 99%, which reflects the ability of the hierarchical network to prevent agglomeration of the iron-oxide nanoparticles.
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[ Last edited by maintech on 2013-4-11 at 21:54 ] |