氧化銅催化劑應用於鋅-空氣燃料電池陰極之研究

Abstract

金屬-空氣燃料電池由於結構簡單、高能量密度、性能穩定、高發電效率及對環境影響較低等優點，被應用於低消耗功率的電子產品，特別是鋅-空氣燃料電池因為擁有高的實際比能量因此最受重視。為了能夠使鋅-空氣燃料電池在大電流下放電，必須使空氣陰極中氧還原反應速率增加。 本研究是以結構簡單、容易合成之氧化銅為催化劑，以ACP法及共沉澱法製備出不同表面活性的CuO，並提高其結晶性，且利用H2O2分解反應測試其催化效能，同時考量比表面積的因素，求出單位表面積之催化活性，藉以判斷催化劑的催化能力，結果顯示以ACP法在500℃鍛燒及以CuCl2為起始反應物共沉澱產生之CuO催化效能最好。在本研究中，將原有製備空氣陰極的製程加以改良，提高催化劑及PTFE在XC-72中的分散性，結果顯示改善後的製程能提高原有空氣陰極的性能。 本研究利用常用之電化學分析方法，包括I-V放電測試、循環伏安法及極化曲線分析，針對各不同活性之CuO所製成的空氣電極作測試，結果顯示I-V放電測試中，以ACP法在500℃鍛燒及以CuCl2為起始反應物共沉澱合成之CuO的效能最佳。根據循環伏安法可得知，CuO能有效的將氧還原反應加速，但其反應機制仍不明確。以極化曲線分析各催化劑之空氣電極，結果顯示CuO對於氧的還原能力較MnO2高，但受限於空氣陰極的導電度較低，無法完全發揮應有之性能。以陽極極化曲線分析各空氣電極，發現以CuO對氧氣的生成反應有明顯的加速能力。

Metal-air fuel cell has been used in low power consumed electric device, because of their simple structure, high power density, stable performance, high efficiency, low environmental influences and other advantages. Especially zinc-air fuel cell has been paid most attention because they have high specific energy. To make the zinc-air fuel cell reached high discharge current, it has boosted the reaction rate of oxygen reduction of the air electrode. This study is use CuO which has simple structure and easily synthesis as the catalyst. The different surface activity catalysts was prepared by using amorphous citrate precursor method and co-precipitation method, and further increase the degree of crystallization. Catalytic activity for catalyst uses the H2O2 decomposition reaction, and considers the influence of the surface area. Further figures out the catalytic activation per unit surface area. The results of the catalytic activity were found that CuO by using ACP method and co-precipitation method via CuCl2 has better activity. In this study we modify the procedure of air electrode, the battery test results higher discharging performance because of high dispersion of catalysts and PTFE in the supporter. The investigation is via the utilization of familiar electrochemical methods including the I-V discharging measurement, the cyclic voltammetry and the polarization curve analysis. The various catalysts for air cathode were carried out the electrochemical testing. In the I-V discharging measurement, the results show that the CuO by using ACP method and co-precipitation method via CuCl2 has best battery performance. By using cyclic voltammetry analysis, we observe the similar figure with MnO2. It is show that CuO has the ability to improve the oxygen reduction, but the mechanism is uncertain. The resulting polarization curves show that CuO has better oxygen reduction ability than MnO2. The conductivity of air electrode is not good enough leads the CuO air electrode have slightly better performance. The anodic polarization curves show that CuO has the ability to precede the oxygen evolution, and the reaction rate was higher than MnO2.