Ultrasonic assisted highly porous PPy/JSAC/IMO [PJ-IMO] nanocomposite for hydrogen fuel cell and asymmetric supercapacitor (PJ-IMO||JSAC) applications

Abstract

Environmental pollution due to irrepressible consumption of fossil fuel and thereby chaotic global temperature enforce the scientific community to search for alternative clean and green energy sources. Hydrogen is considered as a clean, green and alternative energy carrier that has the potential to overcome various environmental issues including the energy crisis. Hence, the present work focuses on the preparation of novel nanocomposite [PPy/JSAC/IMO (PJ-IMO)] comprise of conducting polymer namely polypyrrole (PPy), activated carbon from jack fruit seed (JSAC) and natural clay imogolite (IMO) nanotube where a facile ultrasonic method was adopted for the preparation of PJ-IMO nanocomposite. The structural, morphological and elemental composition of the prepared PJ-IMO nanocomposite reveals that the PPy and IMO were anchored at the surface of JSAC. A drastic increment in the specific surface area of PJ-IMO nanocomposite (1354 m2 g−1) was observed compared to PPy/JSAC (PJ) nanocomposite (892 m2 g−1) and pristine PPy (39 m2 g−1). The prepared PJ-IMO exhibits 7.4 wt% hydrogen storage capacity at 50 °C, desorption of stored hydrogen at 104 °C and very good cyclic stability even after 34 cycles. The calculated binding energy (0.33–0.50 eV) of stored hydrogen falls in the recommended range of US Department of Energy (DOE-2025) targets. The electrochemical hydrogenation studies show that a maximum hydrogen discharge capacity of 3820 mAh/g at 42nd cycle, columbic efficiency of 93.1 %, hydrogen retention rate of 73.8 % and corrosion resistance of 26.3 mA/cm2 respectively. The as-fabricated PJ-IMO||JSAC asymmetric supercapacitor (ASC) has an energy density of 203 Wh kg−1 at 0.5 Ag−1 and power density of 2398 W kg−1 at 2 A g−1. The prepared ASC could able to power blue LEDs for 10 min and motor fan for 7 min. Hence, these excellent characteristics proved that the prepared PJ-IMO nanocomposite may serve as an excellent weakly chemisorbed hydrogen storage material and electrode for electrochemical energy storage applications in the near future.