A self-standing binder-free biomimetic cathode based on LMO/CNT enhanced with graphene and PANI for aqueous rechargeable batteries

The electrochemical parameters of a novel binder-free self-standing biomimetic cathode based on lithium manganese oxide (LMO) and carbon nanotubes (CNT) for rechargeable Lithium-ion aqueous batteries (ReLIAB) are improved using polyaniline (PANI) core-shell in situ polymerization and graphene (Gr). The fabricated cathode material exhibits the so-called “tectonic plate island bridge” biomimetic structure. This constitution is created by combining three components as shown by a SEM and a TEM analysis: the Gr substrates support an entangled matrix of conductive CNT which connect island of non-conductive inorganic material composed of LMO. The typical spinel structure of the LMO remains unchanged after modifying the basic structure with Gr and PANI due to a simplified hydrothermal method used for synthesis. The Gr and PANI core-shell coating improves the electric conductivity from 0.0025 S/cm up to 1 S/cm. The electrochemical performances of the LMO/CNT-Gr/PANI composite electrode are optimized up to 136 mA h g−1 compared to 111 mA h g−1 of the LMO/CNT. Besides that, the new electrode shows good cycling stability after 200 galvanostatic charging/discharging cycles, making this structure a future candidate for cathode materials for ReLIAB. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Technology Agency of the Czech Republic, TACR: TK03030157THETA program of the Technology Agency of the Czech Republic [TK03030157

Carbon Supported Polyaniline as Anode Catalyst: Pathway to Platinum-Free Fuel Cells

The effectiveness of carbon supported polyaniline as anode catalyst in a fuel cell (FC) with direct formic acid electrooxidation is experimentally demonstrated. A prototype FC with such a platinum-free composite anode exhibited a maximum room-temperature specific power of about 5 mW/cm2Comment: 11 pages, 3 Postscript figures, atricle tex styl

Use of facile mechanochemical method to functionalize carbon nanofibers with nanostructured polyaniline and their electrochemical capacitance

A facile approach to functionalize carbon nanofibers [CNFs] with nanostructured polyaniline was developed via in situ mechanochemical polymerization of polyaniline in the presence of chemically treated CNFs. The nanostructured polyaniline grafting on the CNF was mainly in a form of branched nanofibers as well as rough nanolayers. The good dispersibility and processability of the hybrid nanocomposite could be attributed to its overall nanostructure which enhanced its accessibility to the electrolyte. The mechanochemical oxidation polymerization was believed to be related to the strong Lewis acid characteristic of FeCl3 and the Lewis base characteristic of aniline. The growth mechanism of the hierarchical structured nanofibers was also discussed. After functionalization with the nanostructured polyaniline, the hybrid polyaniline/CNF composite showed an enhanced specific capacitance, which might be related to its hierarchical nanostructure and the interaction between the aromatic polyaniline molecules and the CNFs

Preparation and Application of Electrodes in Capacitive Deionization (CDI): a State-of-Art Review

As a promising desalination technology, capacitive deionization (CDI) have shown practicality and cost-effectiveness in brackish water treatment. Developing more efficient electrode materials is the key to improving salt removal performance. This work reviewed current progress on electrode fabrication in application of CDI. Fundamental principal (e.g. EDL theory and adsorption isotherms) and process factors (e.g. pore distribution, potential, salt type and concentration) of CDI performance were presented first. It was then followed by in-depth discussion and comparison on properties and fabrication technique of different electrodes, including carbon aerogel, activated carbon, carbon nanotubes, graphene and ordered mesoporous carbon. Finally, polyaniline as conductive polymer and its potential application as CDI electrode-enhancing materials were also discussed

One-dimensional nanostructures of conducting polypyrrole: Preparation and properties

In order to expand the possibilities of application of conducting polypyrrole, an optimized method for the synthesis of one-dimensional polymer nanostructures has been developed. By a simple one-step synthesis, polypyrrole is obtained in the form of uniform one-dimensional nanoparticles with diameter 90 nm and aspect ratio more than 50. It is shown that the main properties of one-dimensional polypyrrole (conductivity, specific surface area, absorption in near-infrared and stability) are superior to common bulk polymer with spherical structure of nanoparticles. © 2019 IEEE

Electric properties of MnZn ferrite/polyaniline composites: the implication of polyaniline morphology

(Di)electric properties of MnZn ferrite particles coated by conductive (emeraldine salt) and non-conductive (emeraldine base) forms of PANi were measured and discussed in relation to properties of individual components of such composite. The electric response in a wide frequency (0.1 Hz–10 MHz) and temperature (−150 to 100 °C) range was determined. Recorded relaxation processes were identified as a result of hopping charge carriers, which either only polarize or give rise to DC conductivity. Temperature dependence of conductivity modelled by variable range hopping model indicated different system dimensionality: 3D in PANi bulk and 1D in PANi film, that is result of PANi morphology variation. AC conductivity frequency spectra were well approximated by power law model, and temperature evolution of its exponent was related to the type of charge involved in the charge transport. Altogether, the overlayer of conductive PANi increases by two orders of magnitude the electrical conductivity of ferrite/PANi composite compared to pristine ferrite, whereas non-conductive PANi reduced it by three orders of magnitude. Therefore, the electrical properties of ferrite/PANi composites are determined by electrical properties of PANi, which in turn depend upon mesoscale charge transport in PANi. © 2017, Springer Science+Business Media, LLC.LO1504, NPU, Northwestern Polytechnical UniversityMinistry of Education, Youth and Sports of the Czech Republic-Program NPU I [LO1504