Structure Investigation and Electrochemical Behavior of γ-MnO2 Synthesized from Three-Dimensional Framework and Layered Structures

Abou‐El‐Sherbini, Khaled S.

doi:10.1006/jssc.2002.9608

Cited by 7 publications

(4 citation statements)

References 24 publications

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“…The most promising cathode materials are those with minimum value of pyrolusite and maximum microtwinning. 24 Simulated X-ray diffraction patterns of Li-MnO 2 with microtwinning and high concentration of lithium give better agreement with experimental XRD patterns. Hence one can conclude that the structure is strongly modified, with probably an important decrease of pyrolusite value in the system and appearance of other kinds of defects.…”

Section: Discussionmentioning

confidence: 65%

Amorphization and recrystallization study of lithium insertion into manganese dioxide

Maphanga

Sayle

et al. 2011

Phys. Chem. Chem. Phys.

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Various polymorphs of MnO(2) are widely used as electrode materials in Li/MnO(2) batteries. Electrolytic manganese dioxide (EMD) is the most electrochemically active form of MnO(2) and is very difficult to characterize. Their structural details are still largely unknown owing to the poor quality of X-ray diffraction (XRD) patterns obtained from most MnO(2) samples. Simulated amorphisation and crystallization technique was used to derive microstructural models for Li-MnO(2) which included most microstructural details that one would expect to find in the real material. Specifically, pyrolusite-MnO(2), comprising about 25,000 atoms, was amorphised (strain-induced) under molecular dynamics (MD) and different concentrations of lithium ions were inserted. Each system was then crystallized under MD simulation. The resulting models conformed to the pyrolusite polymorph, with microstructural features including: extensive micro-twinning and more general grain-boundaries, stacking faults, dislocations and isolated point defects and defect clusters. Molecular graphical images, showing the atom positions for the microstructural features together with simulated XRD patterns they give rise to, are presented and compared with measured XRD. The calculated XRD are in accord with experiment thus validating the structural models.

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Section: Discussionmentioning

confidence: 65%

Amorphization and recrystallization study of lithium insertion into manganese dioxide

Maphanga

Sayle

et al. 2011

Phys. Chem. Chem. Phys.

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“…Microtwinning defects can be denoted by the difference between the positions of 1 2 1/1 4 0 and 2 2 1/2 4 0 lines of ramsdellite: a narrowing of the distance between these couples of lines means an increase of Tw [12,14,15].…”

Section: Electrochemical Behaviour and Mineral Structurementioning

confidence: 99%

“…␥-MnO 2 samples can be then classified according to P r and Tw showing that the most promising cathode materials are those with minimum P r and maximum Tw [15] in comparison with commercial EMD, which are characterised by P r ∼ = 50 and Tw > 50 [12].…”

Section: Electrochemical Behaviour and Mineral Structurementioning

confidence: 99%

Preparation and characterisation of chemical manganese dioxide: Effect of the operating conditions

Pagnanelli

Sambenedetto

Furlani

et al. 2007

Journal of Power Sources

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“…and excellent chemical characteristics. Li batteries which are one of the important applications have been widely studied [3][4][5][6][7][8][9]. In addition, MnO 2 has been used for catalysts [10][11][12][13], supercapacitors [7,[14][15][16][17], and so forth.…”

Section: Introductionmentioning

confidence: 99%

Synthesis ofα-MnO₂Nanomaterial from a Precursorγ-MnO₂: Characterization and Comparative Adsorption of Pb(II) and Fe(III)

Dinh

Nguyen

et al. 2016

Journal of Chemistry

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α-MnO2nanostructure was successfully synthesized via hydrothermal treatment of a precursorγ-MnO2. Structure, morphology, and BET surface area were characterized using X-ray powder diffraction (XRD), Scanning Electron Microscopy (SEM), and Brunauer-Emmett-Teller nitrogen adsorption (BET-N2adsorption). Thermal analysis result showed thatα-MnO2nanorods were formed fromγ-MnO2at 600°C. In addition, Pb(II) and Fe(III) adsorptive properties were investigated in an optimal condition. Results showed that equilibrium adsorption was obtained after 60 minutes for Pb(II) at pH = 4.0 and 80 minutes for Fe(III) at pH = 3.5 with 240 rpm of shaking speed overall. Experimental data was analyzed using three models: Langmuir, Freundlich, and Sips. Adsorption capacities (qm) from the Langmuir isotherm models are 124.87 mg/g for Pb(II) and 30.83 mg/g for Fe(III). Along with the highest corelation coefficients, it is clear that the adsorption of Pb(II) and Fe(III) ions onα-MnO2surface followed Sips model. Kinetic studies indicated that the uptake of Pb(II) and Fe(III) occurred in the pseudo-second-order model with two stages for Pb(II) and three stages for Fe(III).

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Structure Investigation and Electrochemical Behavior of γ-MnO2 Synthesized from Three-Dimensional Framework and Layered Structures

Cited by 7 publications

References 24 publications

Amorphization and recrystallization study of lithium insertion into manganese dioxide

Amorphization and recrystallization study of lithium insertion into manganese dioxide

Preparation and characterisation of chemical manganese dioxide: Effect of the operating conditions

Synthesis ofα-MnO₂Nanomaterial from a Precursorγ-MnO₂: Characterization and Comparative Adsorption of Pb(II) and Fe(III)

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Structure Investigation and Electrochemical Behavior of γ-MnO2 Synthesized from Three-Dimensional Framework and Layered Structures

Cited by 7 publications

References 24 publications

Amorphization and recrystallization study of lithium insertion into manganese dioxide

Amorphization and recrystallization study of lithium insertion into manganese dioxide

Preparation and characterisation of chemical manganese dioxide: Effect of the operating conditions

Synthesis ofα-MnO2Nanomaterial from a Precursorγ-MnO2: Characterization and Comparative Adsorption of Pb(II) and Fe(III)

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Product

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Synthesis ofα-MnO₂Nanomaterial from a Precursorγ-MnO₂: Characterization and Comparative Adsorption of Pb(II) and Fe(III)