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Amorphization and recrystallization study of lithium insertion into manganese dioxide

Maphanga, R.R., Sayle, D.C., Sayle, T.X.T., Ngoepe, P.E. (2011) Amorphization and recrystallization study of lithium insertion into manganese dioxide. Physical Chemistry Chemical Physics, 13 (4). pp. 1307-1313. ISSN 14639076 (ISSN). (doi:10.1039/c0cp00274g) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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Abstract

Various polymorphs of MnO2 are widely used as electrode materials in Li/MnO2 batteries. Electrolytic manganese dioxide (EMD) is the most electrochemically active form of MnO2 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 MnO2 samples. Simulated amorphisation and crystallization technique was used to derive microstructural models for Li-MnO2 which included most microstructural details that one would expect to find in the real material. Specifically, pyrolusite-MnO2, comprising about 25000 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. © 2011 the Owner Societies.

Item Type: Article
DOI/Identification number: 10.1039/c0cp00274g
Additional information: Unmapped bibliographic data: LA - English [Field not mapped to EPrints] J2 - Phys. Chem. Chem. Phys. [Field not mapped to EPrints] AD - Materials Modelling Centre, School of Physical and Mineral Sciences, University of Limpopo, Private Bag x 1106, Sovenga 0727, South Africa [Field not mapped to EPrints] AD - DEAS, Cranfield University, Defence College of Management and Technology, Shrivenham SN6 8LA, United Kingdom [Field not mapped to EPrints] DB - Scopus [Field not mapped to EPrints]
Subjects: Q Science
Divisions: Faculties > Sciences > School of Physical Sciences > Functional Materials Group
Depositing User: Dean Sayle
Date Deposited: 06 Mar 2015 16:33 UTC
Last Modified: 29 May 2019 14:06 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/46782 (The current URI for this page, for reference purposes)
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