摘要: | 本研究是利用中國碳素鋼鐵公司提供之活性碳做為超高電容器的電極,並調控不同持溫的溫度、不同熱處理氣氛以及活性碳本身顆粒大小;藉以探討活性碳表面官能基和活性碳顆粒大小對超高電容器性質的影響,而其中電解液是選用商業上較常運用的1 M TEABF4/PC (Tetraethylammonium Tetrafluoroborate)/(Propylene Carbonate)做為電解液。 首先探討不同熱處理溫度對電容器的影響:本實驗在450 oC、600 oC、750 oC、850 oC、950 oC氮氣下進行熱處理,由材料分析能夠觀察到:隨著熱處理溫度提高,除了降低活性碳比表面積外、其表面含氧官能基含量也隨之下降;在電化學分析方面,提高溫度江造成的比表面積減少,其結果反應在低速電容值的下降;然而表面含氧官能基含量的減少能增進電容器的耐用度(循環穩定性、高速穩定性、漏電流特性等)。 根據上述實驗結果,進一步討論在750 oC下不同氣氛下進行熱處理對電容器的影響;比較N2、NO、NH3、Melamine等氣氛,預期透過氮摻雜提高電容器的性能。由材料分析中能發現:使用不同熱處理方式皆能有效的對碳材進行摻氮,其中以Melamine所摻雜之氮含量最多;電化學分析方面,顯現NO熱處理方式在穩定性上有較佳的表現。 另一方面,將不同粒徑分布的活性碳透過750 oC氮氣熱處理,試觀察不同粒徑尺寸對於超高電容器性質的影響。在材料分析中能夠得知:隨著粒徑尺寸越小,其碳材表面所含氧官能基的量也越多,進而影響電容器的電化學性質(循環穩定性、高速穩定性、漏電流特性等)。 ;In the present study, the activated carbon obtained from China Carbon Steel Company was used as the electrode for the super capacitor. The different heat treatment temperature, atmosphere, and the particle size of activated carbon were controlled and their effects were studied comprehensively to understand the electrochemical behavior of super capacitor. 1M TEABF4 (Tetraethylammonium Tetrafluoroborate)/PC (Propylene) was used as an electrolyte. The effects of different heat treatment temperatures (450, 600, 750, 850 and 950 °C) on the capacitors were investigated. This study shows that with increasing the heat treatment temperature, the oxygen content on the surface of activated carbon and the specific surface area reduced leading to decrease in the capacitance at low-current density. However, the decrease in the content of the oxygen-containing functional groups can improve the durability of the capacitor (cycle stability, high-rate performance, leakage current characteristics, etc.). On the basis of the above experimental results, the effects of heat treatment on the capacitors were investigated under different atmospheres at 750°C. Also, we doped Nitrogen in the activated carbon by using different heat treatment atmosphere (Melamine, NO, and NH3) to improve the performance of the capacitors. Further, the activated carbon with different particle size distribution was heat treated at 750 °C in the nitrogen atmosphere. The effect of particle size on the properties of super capacitor was investigated. It is found that the smaller the particle size, the more the amount of oxygen functional groups is contained on the surface of the carbonaceous material and as result of which affects the electrochemical properties of the capacitor (cycle stability, high-speed stability, leakage current characteristics, etc.). |