Polyaniline–Graphene Hydrogel Hybrids via Diffusion Controlled Surface Polymerization for High Performance Supercapacitors

Abstract

The intricate design of nanomaterials through the controlled diffusion process is natural for biological bodies; however, understanding this mechanism for the development of morphology tuned nanomaterials in the practical chemical synthesis process is still lacking. Herein, we present the development of graphene hydrogel via ultrafast assembly and employed it as a diffusion controlled confined reactor for the growth of ultrafine polyaniline nanostructure directly over its hydrogel surface (PANI–GH). The significant control over the polymerization rate is achieved by slowing the diffusion of monomers through the hydrogel–organic interface and subsequent confined polymerization within the porous compartments of graphene hydrogel. In addition, the strong attractive interaction of aniline monomer with the graphene surface plays a key role in controlling the oriented nucleation process, as revealed from the molecular dynamics study. The as-developed PANI–GH with commercial scale mass loading (8.8 mg cm–2) exhibits excellent supercapacitive performance, displaying a capacitance of 503 F g–1 and superb retention (95.8%) even after 3000 charge–discharge cycles. More importantly, it showed a very high rate capability with a capacity retention of 88.6% when the current density increased from 2 to 30 A g–1. This fundamental understanding of the hydrogel mediated interfacial reaction together with outstanding performance metrics of the as-developed material could open up a versatile platform for morphology tuned graphene based functional hybrids.

Synergetic Effect of Polyaniline and Graphene in Their Composite Supercapacitor Electrodes: Impact of Components and Parameters of Chemical Oxidative Polymerization

“…Sikdar et al used different ratios between ANI (3.2 mmol) and APS (0.16, 8, 16 mmol) to prepare solutions in HCl before immersing RGO hydrogel (GH) there and the polymerization of PANI [ 93 ]. After controlled saturation process, the as-formed hybrids had different mass loadings from 3 mg/cm 2 (PANI-GH1 with the lowest APS content) to 8.8 mg/cm 2 (PANI−GH3 with the highest APS amount).…”

“…All prepared electrodes exhibited EDLC behaviour with pseudocapacitive energy storage. Moreover, PANI-GH3, which contains the highest loading of PANI (83%) with respect to the weight of the hydrogel, thus presented the highest capacitance value of 503 F/g at a current density of 5 A/g followed by PANI-GH2 (80.7% PANI loading) and PANI−GH1 (50% PANI loading) [ 93 ].…”

“…In summary, the specific capacitance can grow with increase of APS content due to higher polymer molecular mass and hence mass loading [ 93 ]. At the same time, the mass loading of active material can depend on used acid, being most enhanced by HCl, that results as well in high areal capacitance [ 95 ].…”

Energy Storage Application of Conducting Polymers Featuring Dual Acceptors: Exploring Conjugation and Flexible Chain Length Effects

“…Unlike metal oxides, CPs benefit from rapid reversible redox reactions near the electrode surface and bulk owing to the conjugation effect generated by fused heterocyclic structures where electrical energy can be stored. [ 5–8 ]…”

“…Unlike metal oxides, CPs benefit from rapid reversible redox reactions near the electrode surface and bulk owing to the conjugation effect generated by fused heterocyclic structures where electrical energy can be stored. [5][6][7][8] In the past decade, electron-donating CPs such as poly(3,4-ethylenedioxythiophene) (PEDOT), polyaniline (PANI), polypyrrole (PPy), and polythiophene (PTh) have attracted significant attention for energy storage applications. [9][10][11] The particular interest is in the reverse dopingdedoping behavior that has been favored for various advanced electronic devices such as batteries, supercapacitors, and sensors.…”