Electric double layer capacitance of multi-walled carbon nanotubes and B-doping effect
Electric double layer capacitance of multi-walled carbon nanotubes and B-doping effect
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DOI：
10.1007/s00339-005-3399-6
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发表时间：
2006-03-01
影响因子：
2.7
通讯作者：
Hishiyama, Y
中科院分区：
文献类型：
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作者：
Shiraishi, S;Kibe, M;Hishiyama, Y
以碳酸丙烯为电解液，研究了CVD法制备的多壁碳纳米管（MWCNTs）的双层电容性能。原始的MWCNTs通常是缠绕管，外径约为20 nm，内径约为5 nm， BET比表面积约为220 m(2) g（-1）。在三电极系统中的恒流测量（40 mAg(-1)， 2类似于4 V vs. Li/Li+）显示15 Fg（-1）的重量电容和该特性的良好速率。由于尖端被热氧化打开，比表面积和电容增加。相比之下，在3000℃下热处理，由于缺陷恢复，MWCNT的表面积和电容减小。少量（< 1 at）用含硼石墨坩埚在2200℃或2300℃进行热处理，将%)的硼掺杂到MWCNT中。b掺杂可以提高MWCNTs的单位表面积比电容，同时保持管状结构不变。b掺杂对电容的影响可以用碳空间电荷层的修饰来解释。
The double layer capacitance properties of multi-walled carbon nanotubes (MWCNTs) prepared by CVD were investigated using propylene carbonate electrolytes. The original MWCNTs are typically entangled tubes with 10 similar to 20 nm outer diameter, around 5 nm inner diameter, and around 220 m(2) g(-1) of BET specific surface area. The galvanostatic measurement (40 mAg(-1), 2 similar to 4 V vs. Li/Li+) in a three-electrode system showed 15 Fg(-1) of gravimetric capacitance and a good rate of this property. Due to the tips opening by thermal oxidation, the specific surface area and the capacitance increased. In contrast, heat-treatment at 3000 degrees C decreased the surface area and the capacitance of the MWCNT due to defect recovery. A small amount (< 1 at. %) of boron was doped to the MWCNT by heat-treatment at 2200 degrees C or 2300 degrees C with a B-contained graphite crucible. The B-doping can improve the specific capacitance per surface area for the MWCNTs while maintaining the tube morphology. This effect of B-doping on the capacitance can be explained by modification of the space charge layer in carbon.