Electrochemical deposition of highly loaded polypyrrole on individual carbon nanotubes in carbon nanotube film for supercapacitor

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 337; pp. 552 - 559
• Main Authors: Chang, Zhi-Han, Feng, Dong-Yang, Huang, Zi-Hang, Liu, Xiao-Xia
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.04.2018
• Subjects: Carbon nanotube film; Core-shell structure; Highly loaded polypyrrole; Supercapacitor; Supercapacitor; Highly loaded polypyrrole; Core-shell structure; Carbon nanotube film
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2017.12.095

[Display omitted] •Electrochemical pretreatment of CNT film to get loosely structured ECNT film.•Electrodeposition of highly loaded PPy on individual carbon tubes in ECNT film.•Large capacitance of 965.3 mF cm−2 at 1 mA cm−2 for core-shell structured ECNT/PPy.•85.1% capacitance retention upon 20 times current increase for ECNT/PPy.•High energy density of 3.63 mWh cm−3 at 13.86 mW cm−3 for ASC with ECNT/PPy anode. In this work, a core-shell structured pseudocapacitive anode is fabricated through electrochemical deposition of highly loaded (3.89 mg cm−2) polypyrrole (PPy) on individual carbon tubes in electrochemically pretreated carbon nanotube film (ECNT) to afford ECNT/PPy electrode. The core-shell structure significantly promotes the charge transfer for energy storage reaction and buffers the volume change of PPy during charge/discharge cycles, leading to much improved pseudocapacitive behaviors for ECNT/PPy. It can retain 75.2% of its capacitance (965.3 mF cm−2 at 1 mA cm−2) when the discharge current increased 40 times to 40 mA cm−2. After 10,000 galvanostatic charge/discharge cycles, ECNT/PPy can maintain 89.1% of its initial capacitance. The asymmetric supercapacitor (ASC) assembled by using ECNT/PPy and CNT/MnO2 as anode and cathode, respectively demonstrate a high volumetric energy density of 3.63 mWh cm−3 at the power density of 13.86 mW cm−3. After 10,000 galvanostatic charge/discharge cycles, the ASC can retain 89.0% of its capacitance, showing its good cyclic stability.