Enhanced Storage Performance of PANI and PANI/Graphene Composites Synthesized in Protic Ionic Liquids

Abstract

Polyaniline (PANI) was synthesized using oxidative polymerization in a mixture of water with pyrrolidinium hydrogen sulfate [Pyrr][HSO4], which is a protic ionic liquid PIL. The obtained PANI (PANI/PIL) was compared with conventional PANI (PANI/HCl and PANI/HSO4) in terms of their morphological, structural, and storage properties. The results demonstrate that the addition of this PIL to a polymerization medium leads to a fiber-like morphology, instead of a spherical-like morphology, of PANI/HSO4 or an agglomerated morphology of PANI/HCl. In addition, PAN/PIL exhibits an improvement of the charge transfer kinetic and storage capability in H2SO4 1 mol·L−1, compared to PANI/HCl. The combination of PANI/PIL and graphene oxide (GO), on the other hand, was investigated by optimizing the PANI/GO weight ratio to achieve the nanocomposite material with the best performance. Our results indicate that the PANI/PIL/GO containing 16 wt% of GO material exhibits a high performance and stability (223 F·g−1 at 10 A·g−1 in H2SO4 1 mol·L−1, 4.9 Wh·Kg−1, and 3700 W·Kg−1 @ 10 A·g−1). The obtained results highlight the beneficial role of PIL in building PANI and PANI/GO nanocomposites with excellent performances for supercapacitor applications.

Non-Substituted Imidazolium-Based Electrolytes as Potential Alternatives to the Conventional Acidic Electrolytes of Polyaniline-Based Electrode Materials for Supercapacitors

“…The electrochemical performances of PANI/PIL were studied in a three-electrode system configuration using the three different kinds of PIL-based aqueous electrolytes: ] aq each presenting a redox couple, whose potential varied with different PILs being used. This redox couple is typically observed for PANI characterized in the conventional aqueous electrolytes [11,19]. It is associated with the reversible transformation between leucoemeraldine base (semiconducting state) and emeraldine salt (conducting state) forms [23,[47][48][49][50].…”

“…It is possible to categorize these combinations between PANI and ionic liquids into three approaches. The first approach (approach I) consists of focusing on the morphology of PANI alert by replacing the conventional acidic polymerization media with ionic liquids, followed by an electrochemical investigation of the obtained nanostructured PANI in the conventional electrolytes [ 3 , 18 , 19 , 20 , 21 , 22 ]. The second approach (approach II) concentrates on the electrochemical study of the PANI in the ionic liquid-based electrolytes [ 23 , 24 , 25 ].…”

Protic ionic liquids for sustainable uses

“…A recent study by Al-Zohbi et al is also notable for using [HHpyrr][HSO 4 ] rather than an amino-acid-based PIL. 237 By combining it with polyaniline and nanomaterials, the authors produced electrodes that performed well in acidic conditions ( cf. [Lys][HSO 4 ] 2 + K 2 CO 3 activation 233 ), but without requiring an activation step.…”

“…[Lys][HSO 4 ] 2 + K 2 CO 3 activation 233 ), but without requiring an activation step. 237 Cycle stability was investigated to only 1000 cycles with capacitance retention at 73% for their best system, but this study invites greater exploration of PILs in combination with conductive polymers, particularly as the PIL was shown to give rise to favourable nanofiber-type morphology with high surface areas that are ideal for supercapacitor applications.…”

“…[Lys][HSO 4 ] 2 + K 2 CO 3 activation 233 ), but without requiring an activation step. 237 Cycle stability was investigated to only 1000 cycles with capacitance retention at 73% for their best system, but this study invites greater exploration of PILs in combination with conductive polymers, particularly as the PIL was shown to give rise to favourable nanofiber-type morphology with high surface areas that are ideal for supercapacitor applications. Overall, it is apparent that studies in this area rarely benchmark the system under investigation against a more classical porous carbon fabrication process, such that assessing the techno-economic balance between traditional and new PILbased procedures is challenging.…”