聚苯胺
假电容
超级电容器
循环伏安法
材料科学
电容
介电谱
扫描电子显微镜
纳米纤维
电导率
电极
化学工程
分析化学(期刊)
电化学
复合材料
化学
有机化学
工程类
物理化学
聚合
聚合物
作者
Hanlu Li,Jixiao Wang,Qingxian Chu,Zhi Wang,Fengbao Zhang,Shichang Wang
标识
DOI:10.1016/j.jpowsour.2009.01.052
摘要
The theoretical mass specific capacitance (Cs) of polyaniline (PANI) is firstly estimated by combining electrical double-layer capacitance and pseudocapacitance. The maximum Cs is 2.0 × 103 F g−1 for one single PANI electrode. In present work, the PANI nanofiber modified stainless-steel (SS) electrode (PANI/SS) was used to assemble supercapacitors. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images indicate that the PANI nanofiber has a coarse surface arising from the heterogeneous structure which likes an aggregation of nanoparticles. The performance of the assembled PANI/SS supercapacitors was investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge/discharge methods in 1.0 M H2SO4. The maximum Cs obtained from these methods in present work is 608, 445.0, and 524.9 F g−1, respectively, which is only 30%, 22%, and 26% of the theoretical one. The significant difference between the experimental and the theoretical value indicates that only a low percentage of PANI (effective) has contribution to capacitance. The percentage of effective PANI depends on both the diffusion of dopants (counter-anions) and the conductivity of PANI. Under practical conditions, the former factor makes PANI nanofiber behave like a concentric cable with only the shell part involved in the charge/discharge process. The latter one which determines the electron transfer rate in PANI has an influence on the degree of redox reaction. In present work, the heterogeneous structure of the PANI nanofiber has a negative effect on the conductivity.
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