Facile fabrication of MnO₂-embedded 3-D porous polyaniline composite hydrogel for supercapacitor electrode with high loading

Abstract

To obtain the promising pseudocapacitance of MnO2, the composite hydrogel of MnO2 and polyaniline (PANI) was fabricated using in situ polymerization of aniline hydrochloride in the aqueous solution containing commercial MnO2 nanoparticles and additives. Both scanning electron microscopy and transmission electron microscopy results indicated that the composite hydrogel exhibited a 3-D porous structure, within which MnO2 nanoparticles were uniformly embedded. The investigations of cyclic voltammetry, galvanostatic charge−discharge, and electrochemical impedance spectroscopy demonstrated superior supercapacitor (SC) performance of the hydrogel electrode even with high loading. The electrode with loading of 1.5 mg cm–2 showed a favorable specific capacitance (293 F g–1, 10 mV s–1), which only decreased to 258 F g–1 when the loading of the electrode was seven times higher (10.8 mg cm–2). Furthermore, the hydrogel electrode displayed good cycle stability in the acidic solution (81% capacitance retention after 1000 charge/discharge cycles). The favorable electrochemical performance of the composite hydrogel should be attributed to the fast electron/ion transport and good protection for MnO2 in the 3-D porous structure. Due to the facile one-pot synthesis and optimized nanostructure, it could be expected that MnO2-embedded 3-D porous PANI composite hydrogels have great application in the field of high-performance electrode with high loading for SCs.

A review on graphene based transition metal oxide composites and its application towards supercapacitor electrodes

“…Many researchers have reported different types of separator between graphene sheets to improve the capacitance and energy density. Like Pt, SnO 2 , Ni(OH), Ni(OH) 2 , Co(OH) 2 , MnO 2 [172,175,176,178] and also transition metals are used as spacers in graphene sheets such as Co 3 O 4 , Fe 3 O 4 , Cu-O, Ni(OH) 2 , MnO 2 ,, RuO 2 and conductive polymers such as polyanilines (PANI), polypyrrole (PPy) and polythiophene (PT) [179][180][181]. The structural morphologies of intercalated graphene with Ni (OH) 2 are shown in Fig.…”

Enhancement of conductivity, mechanical and biological properties of polyaniline-poly(N-vinylpyrrolidone) cryogels by phytic acid

“…They are designed to combine intrinsic physicochemical characteristics of PANI with mechanical and chemical properties of the supporting polymer to overcome inherent brittleness of the conducting polymer for improved handling properties and opening new potential application options. Being a subclass of conducting polymer hydrogels, cryogels can be used in similar ways, for example, as sensors [2][3][4], supercapacitors [5,6], antibacterial materials [7,8], in tissue engineering [9,10] and drug-delivery [11,12]. Polyaniline cryogels are prepared by oxidative polymerization of aniline in a frozen medium containing a water-soluble polymer [1].…”

Injectable Antibacterial Gelatin-Based Hydrogel Incorporated with Two-Dimensional Nanosheets for Multimodal Healing of Bacteria-Infected Wounds

“…The XRD profile of the MnO 2 nanosheets exhibited four peaks centered at 2θ = 12.2°, 24.2°, 38.2°, and 52.2°, which are in line with the characteristic peaks of δ-MnO 2 (Figure F) . As demonstrated, the strong peaks of MnO 2 and FeCl 3 almost disappeared from the diffractograms of the Gel-Fe and Gel-Fe-MnO 2 hydrogels, which shows an interaction between the gelatin network and the Fe ions and MnO 2 nanosheets …”

“…20 As demonstrated, the strong peaks of MnO 2 and FeCl 3 almost disappeared from the diffractograms of the Gel-Fe and Gel-Fe-MnO 2 hydrogels, which shows an interaction between the gelatin network and the Fe ions and MnO 2 nanosheets. 30 The morphologies of Gel, Gel-Fe, and Gl-Fe-MnO 2 were determined by scanning electron microscope (SEM). The effect of Fe 3+ and MnO 2 cross-linking on the morphology of the hydrogels was examined by SEM to reveal that the surface morphologies and porous structures of the Gel, Gel-Fe, and Gel-Fe-MnO 2 hydrogels were significantly different (Figure 3A).…”