以多层次聚苯胺颗粒为电极活性物质的超级电容器的电化学性能

Electrochemical Performances of Supercapacitor with Polyaniline Particles with Hierarchy as Active Electrode Material

以(NH4)2S2O8为氧化剂用化学氧化法合成了具有多层次结构的聚苯胺颗粒,其二次颗粒由一次颗粒集结而成,一次颗粒的粒径基本上在1μm以下,一次颗粒由多层微小薄片叠合而成.用这种聚苯胺为活性物质制成电极,以2mol·L-1的H2SO4水溶液作电解液,组装成了聚苯胺电极超级电容器.用循环伏安法、电化学阻抗谱和恒电流充放电技术测试了该超级电容器的电化学性能.在7mA的充放电电流下,它的比能量可达6.35Wh·kg-1,比功率可达132W·kg-1,电极材料的比容量可达408F·g-1.在20mA的充放电电流下,它的比能量可达4.39Wh·kg-1,比功率可达328W·kg-1,电极材料的比容量可达324F·g-1.在100次的充放电循环中,聚苯胺电极超级电容器的电容量没有下降,电荷充放电效率一直保持在95%左右.

Polyaniline (PANT) particles with hierarchy are prepared by adding (NH4)(2)S2O8 dropwise into aqueous solution containing aniline monomer and HCl acid at 0 degrees C under nitrogen atmosphere with stirring. SEM images show that the resulted PANT particles are composed of their primary particles, which are composed of multi-layer flakes. Symmetric redox supercapacitor (prototype) is assembled with the PANT particles as active electrode materials and 2 mol . L-1 H2SO4 aqueous solution as electrolyte. The electrochemical performances of the supercapacitor are tested with cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedancespectroscopy. When the charge-discharge current is 7 mA, the specific energy and specific power of the supercapacitor can reach 6.35 Wh . kg(-1) and 132 W . kg(-1) (based on the mass of PANi), respectively; the capacitance of PANT electrode is about 408 F.g(-1). When the charge-discharge current is 20 mA, the specific energy and specific power of the supercapacitor can reach 4.39 Wh .kg(-1)and 328 W . kg(-1) (based on the weight of PANi), respectively; the capacitance of PANT electrode is about 324 F.g(-1). During 100 charge-discharge cycles, the discharge capacity of the supercapacitor is constant,and the charge-discharge efficiency is 95%. The results show that the PANT supercapacitor with hierarchial particles as active electrode material can store a great deal of charge and energy in H2SO4 solution.