Pristine and nanocomposite (NC) hybrid electrodes
of polyaniline (PANI)-nickel hydroxide [Ni(OH)2] have been
prepared by single and two-step electrodeposition processes, respectively, onto
stainless-steel (SS) substrates. Enhanced reversibility and stability of
amorphous PANI- Ni(OH)2 NC electrodes compared to single
electrode materials have been explored. PANI has a nanofibrous morphology,
Ni(OH)2 has nanoplatelet-type morphology, and the NC
electrodes retain an overall nanofibrous morphology. The maximum specific
capacitance (SC), obtained from integrated charge under voltammetric conditions,
for PANI (electro-deposited for 5 min), NC (electrodeposition of
Ni(OH)2 for 10 min and 20 min onto PANI electrode surface)
and Ni(OH)2 (electrodeposited for 10 min) electrodes, are 0.59,
39.06, 32.36, and 113.8 F/g, respectively, suggesting higher electrochemical
performance of Ni(OH)2 electrode compared to PANI and NC
electrodes. The retention in SC values with faster scan rates from 10 to 100
mV/s for PANI, NC (10 min), NC (20 min) and Ni(OH)2 are 38.7,
61.1, 52.4, and 29.0 %, respectively, explicitly confirming a higher
reversibility in NC electrodes. The retention in SC values with increase of
cycle number up to 1000 for PANI, NC (10 min), NC (20 min) and
Ni(OH)2 electrodes are 34.9, 61.5, 67.5, and 40.7 %
respectively, demonstrating higher electrochemical stability of NC electrodes
over pure-phase electrodes. Nearly 2.15, 79.36, 66.66 and 406.83
mC/cm2 charges on PANI, NC (10 min), NC (20 min) and
Ni(OH)2 electrodes, respectively, are obtained. Inner to
total charge and outer to total charge ratios have been used to explain
contributing sites to total charge in pristine and NC
electrodes.
