Azopolymer triggered electrophoretic deposition of MnO₂-carbon nanotube composites and polypyrrole coated carbon nanotubes for supercapacitors

Abstract

Poly[1-[4-(3-carboxy-4-hydroxyphenylazo)benzenesulfonamido]-1,2-ethanediyl, sodium salt] (PAZO) exhibits a number of unique physical properties, which are important for diverse applications of this functional polymer in photonics, optoelectronics, memory devices and sensors. A conceptually new strategy has been utilized for the fabrication of thin films of PAZO using electrophoretic deposition (EPD). The deposition kinetics and mechanism have been investigated and the advantages of EPD have been discussed. Our new findings in the surface and interface chemistry allowed for the development of surface modification methods, which were utilized for the electrosteric dispersion and EPD of MnO 2 nanofibers, multiwalled carbon nanotubes (MWCNT), polypyrrole (PPy) nanoparticles and PPy coated MWCNT. New method has been developed for the fabrication of PPy coated MWCNT, using bromothymol blue sodium salt as a dopant for PPy and dispersant for MWCNT. The aromatic PAZO monomers, containing chelating salicylate ligands provided multiple adsorption sites for PAZO adsorption on different materials and allowed for their efficient electrosteric dispersion. Another major finding was the possibility of efficient deposition of composites, using PAZO as a co-dispersant for MnO 2 nanofibers and MWCNT. The MnO 2 nanofibers, MWCNT, PPy nanoparticles, PPy coated MWCNT and composites, deposited by EPD, were used for energy storage in electrodes of electrochemical supercapacitors. Testing results showed beneficial effect of PAZO for the dispersion and EPD of advanced supercapacitor materials. The results of this investigation paved the way for EPD of other composites utilizing properties of different functional materials and unique physical properties of PAZO.

Enhancing Bifunctional Catalytic Activity of Oxygen Reduction and Evolution Reaction via One‐Pot Formation of MnO2‐Carbon Hybrid Nanocomposite

“…Among them, the most widely reported approaches are i) solid‐based simple mechanical mixing method, and ii) solution‐based chemical deposition method via self‐limiting surface redox reactions between MnO 4 – and carbon . Although these are very simple and effective ways, the former can provide weak interaction between two components since the chemical bonding is not expected, thus leading to the electrical isolation and catalytic inactivity ,. In the latter case, MnO 2 can be confined to the surface region of carbon, thus leading to a decrease in conductivity and specific surface area, and multi‐step process is also required as follows; carbon synthesis, surface modification and MnO 2 deposition on carbon material through redox reaction (4MnO 4 – + 3C + H 2 O → 4MnO 2 + CO 3 2– + 2HCO 3 – ) …”

Porous spherical NiO@NiMoO4@PPy nanoarchitectures as advanced electrochemical pseudocapacitor materials

“…It is well known that the conductive polymers, such as polypyrrole (PPy), polyaniline (PANI), polythiophene (PTh), poly (3,4ethylenedioxythiophene) (PEDOT), have been widely used to modify electrode materials due to their low cost, ease of synthesis, good mechanical stability and high electronic conductivity [17,18]. Among them, PPy has attracted much attention because of its high electronic conductivity in doped states (10-100 S cm À1 ) and remarkable chemical stability because the additional electrons form inner double bonds are able to move easily through the polymer chain [34][35][36][37]. The polypyrrole is also easily fabricated from the pyrrole monomer through the chemical polymerization route.…”

“…Moreover, polypyrrole is often chosen as the intermediate layer because it has the capacity to perform charge storage by a fast oxidation-reduction reaction, which is widely used as electrode materials for SCs. Hence, a combination of TMOs and PPy is also an efficient strategy to enhance electrochemical performance of SCs [35][36][37]. As far as we know, no reports are available on the use of porous spherical NiO@NiMoO 4 @PPy nanoarchitecture as electrode materials for SCs.…”

Highly flexible all-solid-state supercapacitors based on carbon nanotube/polypyrrole composite films and fibers

“…To improve the performance of the CNT-based supercapacitors, active materials such as MnO 2 , [11][12][13][14] graphene nanosheets, [15][16][17][18] NiCo 2 O 4 , [19] and conductive polymers [20,21] have been coated onto carbon materials as electrodes to achieve a high capacity. To improve the performance of the CNT-based supercapacitors, active materials such as MnO 2 , [11][12][13][14] graphene nanosheets, [15][16][17][18] NiCo 2 O 4 , [19] and conductive polymers [20,21] have been coated onto carbon materials as electrodes to achieve a high capacity.…”