表面活性剂对导电PPY固体铝电解电容器性能的影响

Effects of surfactant on the Performance of Conducting Polypyrrole Aluminum Solid Electrolytic Capacitor

研究了表面活性剂对以导电聚吡咯(PPY Polypyrrole)为阴极的固体铝电解电容器性能的影响.由于电容器的介质膜Al2O3表面状态对沉积其上的PPY薄膜电导率及电容器的电性能影响较大,因此,在对Al2O3介质膜的表面形貌、带电状态和润湿等表面状态进行研究分析的基础上,提出了一种在化学聚合PPY膜时在吡咯单体溶液中添加表面活性剂的新方法.实验结果表明,化学聚合时添加表面活性剂可以使PPY在凹凸不平Al2O3表面充分均匀成膜并且提高了电导率(例如,在比容同为4.3μF/cm2阳极铝箔上的Al2O3膜表面沉积PPY薄膜时,添加与不添加表面活性剂形成的PPY薄膜电导率分别为16.6S/cm和5.4S/cm),所制成的电容器损耗角正切值可降低至0.026,漏电流减小,漏电流常数k值达0.04μA/(μF·V),并具有优良的阻抗频率特性和温度特性.

The effects of surfactants on the perf or mance of conducting polypyrrole(PPY) aluminum solid electrolytic capacitor have been studied in this paper.The cathode of the capacitor was the polypyrrole fil m formed by chemical polymerization on the surface of the dielectric Al2O3 l ayer.It was found that the conductivity of the polypyrrole film and the electri cal properties of the capacitor with polypyrrole film cathode were strongly depe ndent on the surface nature of the Al2O3 layer which was as the substrate f or the polypyrrole film.The surface nature of the Al2O3 layer in reference t o morphology, electric and soakage was investigated and a novel polymerization t echnology by adding surfactants into pyrrole monomer solution was developed . Ex perimental results show that a polypyrrole film with good morphological quality and higher conductivity was formed because the surfactants can be adsorbed on th e Al2O3 layer surface whose nature can be modified(polymerization with and w ithout surfactants conrrespond to the conductivities 16.6 and 5.4 S/cm separatel y).The dissipation factor of the capacitor decreased as low as 0.026 and leakage current constant k droped to 0.04 μA/(μF·V).Furthermore, the capacitors show the low impedance at high frequency and the excellent temperatu re characteristics.