Enhanced capacitance and rate capability of graphene/polypyrrole composite as electrode material for supercapacitors

There has recently been a major thrust toward advanced research in the area of hierarchical carbon nanostructured electrodes derived from cellulosic resources, such as cellulose nanofibers (CNFs), which are accessible from natural cellulose and bacterial cellulose (BC). This research is providing a firm scientific basis for recognizing the inherent mechanical and electrochemical properties of those composite carbon materials that are suitable for carbon-electrode applications, where they represent obvious alternatives to replace the current monopoly of carbon materials (carbon nanotubes, reduced graphene oxide, and their derivatives). Significant promising developments in this area are strengthened by the one dimensional (1D) nanostructures and excellent hydrophobicity of the CNFs, the interconnected pore networks of carbon aerogels, and the biodegradable and flexible nature of cellulose paper and graphenic fibers. Outstanding electrode materials with different dimensions (1D, 3D) are derivable by the strategic choice of cellulose sources. This development requires special attention in terms of understanding the significant impact of the cellulose morphology on the final electrochemical performance. This review article attempts to emphasize the role of the different structural forms and corresponding composites derived from different forms of cellulose, including bacterial cellulose and its varied 3D nanostructures. This article strongly highlights that cellulose deserves special attention as an extremely abundant and extensively recyclable material that can serve as a source of components for electronic and energy devices. Along with emphasizing current trends in electrochemical device components from cellulose, we address a few emerging areas that may lead in future such as enzyme immobilization, flexible electronics, modelling of cellulosic microfibrils. Finally, we have discussed some of the important future prospects for cellulose as source of materials for future.

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3D network of cellulose-based energy storage devices and related emerging applications

Core–sheath structured conductive nanocomposites were prepared by wrapping a homogenous layer of polypyrrole (PPy) around bacterial cellulose (BC) nanofibers via in situ polymerization of self-assembled pyrrole. By manipulating the ordered core–sheath nanostructure, BC/PPy nanocomposites were achieved and outstanding electrical conductivity as high as 77 S cm−1 was obtained with the optimized reaction protocols, i.e., feeding mass ratio of BC/Py 1 : 10, molar ratio of FeCl3/Py 0.5 : 1, molar ratio of HCl/Py 1.2 : 1, volume ratio of DMF–H2O 1 : 2, reaction temperature 0 °C, and reaction time 6 h. The BC/PPy nanocomposites demonstrated promising potential for supercapacitors, with a highest mass specific capacitance hitting 316 F g−1 at 0.2 A g−1 current density. The whole-optimized protocol in preparing highly conductive PPy/BC composites may be readily extended to the preparation of new conductive materials based on core–sheath structured BC nanocomposites for various technological applications.

Core–sheath structured bacterial cellulose/polypyrrole nanocomposites with excellent conductivity as supercapacitors

3D printing of electrically conductive hydrogels for tissue engineering and biosensors - A review

High efficient removal of chromium(VI) using glycine doped polypyrrole adsorbent from aqueous solution

Conducting polymer composites of polypyrrole/yttrium oxide (PPy/Y2O3) were synthesized byin situ polymerization of pyrrole with Y2O3 using FeCl3 as an oxidant. The Y2O3 is varied in five different weight percentages of PPy in PPy/Y2O3 composites. The synthesized polymer composites are characterized by infrared and X-ray diffraction techniques. The surface morphology of the composite is studied by scanning electron microscopy. The glass transition temperature of the polymer and its composite is discussed by DSC. Electrical conductivity of the compressed pellets depends on the concentration of Y2O3 in PPy. The frequency dependent a.c. conductivity reveals that the Y2O3 concentration in PPy is responsible for the variation of conductivity of the composites. Frequency dependent dielectric constant at room temperature for different composites are due to interfacial space charge (Maxwell Wagner) polarization leading to the large value of dielectric constant. Frequency dependent dielectric loss, as well as variation of dielectric loss as a function of mass percentage of Y2O3 is also presented and discussed.

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V. R. Kulkarni

Papers

Synthesis, characterization and a.c. conductivity of polypyrrole/Y 2 O 3 composites