奈米碳管/鎳鈷金屬氧化物複合 電極在超級電容上之應用

CNTs/Ni-Co metal oxide composite electrode for supercapacitors application

蔡宇硯(Yu-Ten Tsai)

指導教授 ： 黃金花

國立清華大學/工學院/材料科學工程學系/碩士(2018年)

摘要

在本研究中，將COOH-多壁奈米碳管(COOH-MWCNTs)散佈於水與酒精之溶液中，並取定量溶液滴於已酸處理過之碳纖維布(Carbon fiber)上並退火，使其形成奈米碳管¬¬-碳纖維布之共構物，再利用脈衝電化學沉積法將鎳鈷氫氧化物沉積於碳管上。在本研究中，針對脈衝電化學沉積的參數，做了一系列的改動及討論，並在此基礎上，額外加入鈷做為參雜元素，藉由調整鎳鈷之間的比例來得到能同時具有良好比電容值及維持率之超級電容器，並在最後針對奈米碳管於碳纖維布上之數量多寡對於電容性質表現有何影響。在使用最佳化參數製作之奈米複合材料電極，在5 mV/s時具有高達1151 F/g的高比電容值，並在經過在20 mV/s掃描3000圈以後，依舊有著84.99%的良好的比電容維持率。而在最後，針對退火條件對於電極之電化學性質之改變進行探討，並利用XPS分析溫度及退火持溫時間對於電極之電化學性質產生何種影響。最終得出結論，當退火程度越高，比電容值會隨之下降，然而在循環壽命及倍率放大維持率上則有明顯進步，反之亦然。

關鍵字

超級電容器 ； 奈米碳管 ； 鎳鈷氧化物 ； 脈衝電化學沉積

並列摘要

In this thesis, a high-performance supercapacitor based on MWCNTs/Ni-Co hydroxide nanocomposites was developed. The MWCNTs on carbon fiber were prepared by the drop-by-drop process, followed by pulse electrodeposition of Ni-Co hydroxide nanoflakes on the surfaces of MWCNTs. The effects of the pulse electrodeposition conditions of Ni-Co hydroxides, including the deposition current density, current-on time, current-off time, deposition cycles and Ni to Co bath ratio, and MWCNTs drop-times were systematically investigated. The optimum deposition conditions were found to be a deposition current density of -0.2 mA/cm2, current-on time of 1 s, current-off time of 3 s, deposition cycles of 600, Ni:Co bath ratio of 3:1, and MWCNTs drop-times of 8. The resulting electrode fabricated under the optimal conditions has exhibited excellent capacitive properties, including a specific capacitance of 1401 F g−1 at 1 A g−1, energy density of ~35 Wh kg−1, power density of ~9 kW kg−1, and capacitance retention of ~85 % after 3000 cycles of operation. The structure-property relationship of the composite electrode was also investigated with different annealing conditions. The results indicate the electrodes subjected to longer annealing time and/or higher annealing temperature would exhibit lower specific capacitance, while better cycling life and rate retention.

並列關鍵字

Supercapacitors ； Carbon nanotube ； Nickel cobalt oxide ； Pulse electrodeposition

參考文獻

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