杂质离子对非晶态水合氧化钌电化学超电容性能的影响

Effect of impurity ions on electrochemical super-capacitive properties of amorphous hydrated ruthenium oxide

采用化学沉淀法(在RuCl_3溶液中滴加NaOH)制备非晶态水合氧化钌,用去离子水对非晶态水合氧化钌沉淀充分洗涤,获得了Na、Cl杂质含量不同、而非晶态结构、水含量和显微相貌都相同的两种氧化钌样品.X射线光电子能谱分析表明,样品中的Na和Cl杂质分别以水合Na^+、水合Cl^-的形式存在.去离子水充分洗涤5次的样品(W-5)与不充分洗涤1次的样品(W-1)相比,前者的Na^+、Cl^-杂质含量低.循环伏安测试表明,W-5的比电容和功率性能都优于W-1 Na^+、Cl^-杂质不仅降低了氧化钉的比电容,也降低了氧化钌的功率性能.在非晶态水合氧化钌的制备过程中杂质含量的控制对获得高超电容性能十分重要.文中还分析了Na^+、Cl^-杂质对电容性能不利影响的机理.

Amorphous hydrous ruthenium oxide was prepared by a chemical precipitation method. Two ruthenium oxide samples with different contents of Na and Cl impurities were obtained by changing the number of times for washing sediments with distilled water. The experiment results showed that the Na and Cl impurities exist as hydrated Na＋ and hydrated Cl？, respectively. Sample W 5 （sufficiently washed 5 times with distilled water during its preparation） has lower content of Na＋ and Cl＋ impurities in comparison with sample W 1 （insufficiently washed once with distilled water during its preparation）. Cyclic voltammetric measurements indicate that the specific capacitance and power performance of W 5 are all higher than that of W 1. Hydrated Na＋ and Cl？ impurities not only decrease the specific capacitance of ruthenium oxide, but degrade the power performance. The reason for the deleterious effect of hydrated Na＋ and Cl^- impurities on the super-capacitive properties is discussed.