垂直奈米碳管/二氧化錳複合電極材料的製備及其於超級電容上之電化學性能探討

Synthesis of Arrayed CNT/MnO2 Composite Electrode and its Electrochemical Performance for Supercapacitor.

彭曉彤(Peng Xiaotong)

指導教授 ： 戴念華

國立清華大學/工學院/材料科學工程學系/碩士(2016年)

摘要

本研究利用快速升降溫化學氣相沉積法製備出垂直的奈米碳管，並以電化學沉積法於奈米碳管上沉積二氧化錳，製備出垂直奈米碳管/二氧化錳複合材料。本研究探討了CNT長度、MnO2於CNT/MnO2中含量以及用以成長CNT之模板型Si基板等因素對CNT/MnO2複合電極材料電容特性的影響。
通過控制奈米碳管的成長時間來控制其長度，得到不同長度的CNT/MnO2複合物，本研究探討的長度分別為20 μm以及250 μm的CNT，發現長度較長的CNT因為導電性更佳而擁有更加高的比電容值。另外，通過控制沉積MnO2的時間來控制CNT/MnO2中MnO2的含量，發現隨著MnO2含量的增加，電極的比電容值呈現先上升後下降的趨勢。對比沉積MnO2之後不同長度的CNT/MnO2，發現長度較短的CNT/MnO2擁有更高的比電容值，其中short-CNT/MnO2(240 s)的電容值達到148 F/g，比long- CNT/MnO2 (160 s)的69 F/g高出許多。為了增加CNT與電解液的接觸面積，本研究使用黃光顯影製程以及反應性離子蝕刻製備模板型Si基板，並用上述方法製備patterned-CNT/MnO2複合電極。通過電化學分析發現，單一patterned-CNT比電容值比long-CNT以及short-CNT都高，這表明增加電極材料與電解液的接觸面積，能夠有效的提升其比電容值，而且patterned-CNT/MnO2 (80 s)的比電容值達到168 F/g。

關鍵字

奈米碳管 ； 超級電容 ； 二氧化麼

並列摘要

This study successfully synthesized aligned carbon nanotube/ manganese dioxide (CNT/MnO2) composite material by rapid heating and cooling chemical vapor deposition followed by electrochemical deposition. Different lengths of CNT/MnO2 composites can be easily obtained by controlling CNT growth durations. The longer CNTs with a length of 250 μm show higher specific capacitance because they possessed higher conductivity as compared with shorter CNTs with a length of 20 μm. The content of MnO2 in the composite, simply controlled by electrochemical deposition time, affected the morphology, microstructure and the capacitive behavior of CNT/MnO2. It is found that the specific capacitance increased with MnO2 amount and decreased when longer MnO2 deposition time was used. Compared with the longer CNT/MnO2, the shorter one exhibits better capacitive behavior; the specific capacitance of short-CNT/MnO2 (240 s) reached 148 F/g which is much higher than 69 F/g of long-CNT/MnO2 (160 s). In order to increase the contact area between CNT and the electrolyte, this study prepared patterned Si substrate using photolithography and reactive ion etching and synthesized patterned-CNT/MnO2. Higher specific capacitance of patterned-CNT/MnO2 was obtained indicating that increasing the contact area could effectively improve the capacitive performance of the electrode; in addition, the patterned-CNT/MnO2 (80 s) demonstrates a high specific capacitance of 168 F/g.

並列關鍵字

Carbon nanotube ； Supercapacitor ； Manganese dioxide

參考文獻

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