A comparative study on long and short carbon nanotubes-incorporated polypyrrole/poly(sodium 4-styrenesulfonate) nanocomposites as high-performance supercapacitor electrodes

Polypyrrole/poly(sodium 4-styrenesulfonate)-carbon nanotubes (PPy/PSS-CNT) nanocomposites have been fabricated with an in situ electrochemically polymerized method. The long (10-30 mu m) and short (0.5-2 mu m) CNT are incorporated separately into the composites, and their effect on the capacitive performance of composites prepared is compared. Scanning electron microscope characterization reveals that long CNT-incorporated composites (PPy/PSS-1CNT) have the more porous microstructure and present a large amount of CNT within the composites, in which these long tangled CNT form an interconnected conductive nano-network. Furthermore, combining with the transmission electron microscopy characterization, both of the two types of composites show the core-shell nanostructure with PPy layer coated on CNT. The results by electrochemical tests including cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS) manifest the PPy/PSS-1CNT composite electrodes have the relatively more superior capacitive behavior and cycle stability than those of the short CNT-incorporated composites (PPy/PSS-sCNT) electrodes. Thereinto, the PPy/PSS-1CNT composite electrodes exhibit a high areal capacitance of 146.1 mF cm(-2) at 10 mV s(-1) CV scan, retaining 94.0% of the initial capacitance after 5000CV cycles. This comparative study suggests that the long CNT-incorporated PPy/PSS-1CNT nanocomposites are relatively more promising as the electrode materials for the high-performance supercapacitors. (C) 2015 Elsevier B.V. All rights reserved.