Reactivity of Nanostructured MnO2 in Alkaline Medium Studied with a Microcavity Electrode: Effect of Oxidizing Agent

Benhaddad, L.; Makhloufi, L.; Messaoudi, Bouzid; Rahmouni, K.; Takenouti, H.

doi:10.1016/s1005-0302(11)60112-6

Cited by 45 publications

(26 citation statements)

References 42 publications

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“…S3d. The rst involves the intercalation/extraction of protons (H 3 O + ) or alkali cations such as Li + , Na + or K + into the bulk of the oxide particles with the concomitant reduction/oxidation of Mn ions: 28,29 MnO 2 + H 2 O + xK + + (x + 1)e À 4 K x MnOOH + OH À (1) shows a schematic diagram of the growth of the products.…”

Section: Resultsmentioning

confidence: 99%

Phase-controlled synthesis of polymorphic MnO₂ structures for electrochemical energy storage

et al. 2015

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Manganese dioxide (MnO 2 ) with a-, b-and d-type structures was controllably synthesized by hydrothermal treatment of an acidic solution of KMnO 4 containing different concentrations of ions at 160 C. The effects of metallic cations, H + and anions on the structures and morphologies of MnO 2 were investigated systematically. The experimental results indicated that cations played a significant part in the formation of MnO 2 with different structures. When K + ions were in competition with H + ions in solution, different MnO 2 structures were formed. a-MnO 2 was formed when the amount of K + was higher than the amount of H + , whereas a higher amount of H + was favorable for the growth of b-MnO 2 structures. When the concentration of K + was much greater than that of H + , d-MnO 2 was obtained. Possible formation mechanisms are proposed based on a series of controlled experiments. The electrochemical properties of supercapacitors based on different types of MnO 2 electrodes were investigated in detail. The specific capacitance measured for MnO 2 strongly depended on the crystallographic structure and decreased in the order a-MnO 2 > d-MnO 2 > b-MnO 2 at a current density of 0.5 A g À1 . A specific capacitance of 535 F g À1 was obtained for a-MnO 2 , but was only 155 F g À1 for b-MnO 2 . a-MnO 2 was more suitable for use as the working electrode at high current densities. Both a-and d-MnO 2 had a poor cycling performance after 3000 cycles, whereas b-MnO 2 showed good stability, maintaining a cycling efficiency of 80% after under the same conditions.

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Section: Resultsmentioning

confidence: 99%

Phase-controlled synthesis of polymorphic MnO₂ structures for electrochemical energy storage

et al. 2015

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“…The chemical synthesis and the characterization of this powder has already been reported in a previous publication [35]. It consisted of a hydrothermal synthesis of MnO 2 powder [37,38] followed by the polymerization of pyrrole using MnO 2 simultaneously as oxidizing agent and template. The polypyrrole powder was chemically prepared by injecting liquid pyrrole (0.2 M) into a beaker containing MnO 2 powder (2 g) suspended in a H 2 SO 4 (100 mL, 1 M) aqueous solution at room temperature.…”

Section: Nanostructured Polypyrrole Powdermentioning

confidence: 99%

Improvement of capacitive performances of symmetric carbon/carbon supercapacitors by addition of nanostructured polypyrrole powder

Benhaddad

Gamby

Makhloufi

et al. 2016

Journal of Power Sources

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International audienceA nanostructured polypyrrole powder was synthesized in a previous work from the oxidation of pyrroleby a nanostructured MnO2 powder used simultaneously as an oxidizing agent and a sacrificial templatein a redox heterogeneous mechanism. In this study, this original PPy powder was used as an activeadditive material with different ratio in carbon/carbon symmetrical supercapacitors whose performanceswere studied by cyclic voltammetry and electrochemical impedance spectroscopy (EIS) using aSwagelok-type cell. From the EIS spectra, the complex capacitance was extracted using a model involvingtwo ColeeCole type complex capacitances linked in series. The specific capacitance values evaluated byEIS and cyclic voltammetry are in a good agreement between them. The results show that the addition ofnanostructured polypyrrole powder improves significantly the specific capacitance of the carbon electrodeand consequently the performances of carbon/carbon supercapacitors. The original and versatilesynthesis method used to produce this polypyrrole powder appears to be attractive for large scaleproduction of promising additives for electrode materials of supercapacitors

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“…Among these synthetic protocols, the wet route is commonly used for the preparation of manganese dioxide [13]. In particular, the effects of pH, concentrations [14], temperature [11,15], reactants [10], counter cations and anions [12] have been widely studied in order to obtain products with different behaviors, morphological structures (e.g. nanotubes, nanowires, nanorods, nanoflowers) and crystalline phases.…”

Section: Introductionmentioning

confidence: 99%

High-performance of bare and Ti-doped α-MnO2 nanoparticles in catalyzing the Oxygen Reduction Reaction

Pargoletti

Cappelletti

Minguzzi

et al. 2016

Journal of Power Sources

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Reactivity of Nanostructured MnO2 in Alkaline Medium Studied with a Microcavity Electrode: Effect of Oxidizing Agent

Cited by 45 publications

References 42 publications

Phase-controlled synthesis of polymorphic MnO₂ structures for electrochemical energy storage

Phase-controlled synthesis of polymorphic MnO₂ structures for electrochemical energy storage

Improvement of capacitive performances of symmetric carbon/carbon supercapacitors by addition of nanostructured polypyrrole powder

High-performance of bare and Ti-doped α-MnO2 nanoparticles in catalyzing the Oxygen Reduction Reaction

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Reactivity of Nanostructured MnO2 in Alkaline Medium Studied with a Microcavity Electrode: Effect of Oxidizing Agent

Cited by 45 publications

References 42 publications

Phase-controlled synthesis of polymorphic MnO2 structures for electrochemical energy storage

Phase-controlled synthesis of polymorphic MnO2 structures for electrochemical energy storage

Improvement of capacitive performances of symmetric carbon/carbon supercapacitors by addition of nanostructured polypyrrole powder

High-performance of bare and Ti-doped α-MnO2 nanoparticles in catalyzing the Oxygen Reduction Reaction

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Phase-controlled synthesis of polymorphic MnO₂ structures for electrochemical energy storage

Phase-controlled synthesis of polymorphic MnO₂ structures for electrochemical energy storage