Hierarchical self-assembled nanoclay derived mesoporous CNT/polyindole electrode for supercapacitors

Abstract

A series of self-assembled and open interconnected mesoporous CNT/polyindole (Pind) electrodes were synthesized by a facile in situ & ex situ approach in the presence of layered silicate material. In the present study, the presence of nanoclay and its electrochemical performance is explored on the imparted hierarchical structure of CNT/Pind (CI) system. The microstructural evolution and coating of Pind on CNT and the nanoclay sheet revealed the formation of a high surface area interconnected mesoporous structure which can efficiently allow easy penetration and rapid transport of electrolyte ions for an improved electrochemical performance. Cyclic voltammetry (CV) analysis at 10 mV s⁻¹ revealed the in situ and ex situ incorporation of the nanoclay to the CNT/Pind system exhibited a 258% and 136% increase in the specific capacitance of the ternary nanocomposite, respectively. These observations were very consistent with the 148% increased specific capacitance of NI (nanoclay/Pind) as compared to Pind. Galvanostatic charging–discharging (GCD) and electrochemical impedance spectroscopy (EIS) also confirmed the improved electronic conductivity and cyclic stability of electrode material. In situ CNI (i.e. CNT/nanoclay/Pind) displayed a better electrochemical performance than ex situ CIN (i.e. CNT/Pind/nanoclay) and other related systems. That the electrode exhibited 96% of the initial specific capacitance retention after 2000 cycles also suggests a high cyclic stability and power delivery uptake of electrode material. It is believed that a nanoclay tailored CNT/Pind nanocomposite can effectively promote their high utilization for SC application.