Mg6MnO8 as a Magnesium-Ion Battery Material: Defects, Dopants and Mg-Ion Transport
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Department of Materials, Imperial College London, London SW7 2AZ, UK
2
Faculty of Engineering, Environment and Computing, Coventry University, Priory Street, Coventry CV1 5FB, UK
*
Author to whom correspondence should be addressed.
Energies 2019, 12(17), 3213; https://doi.org/10.3390/en12173213
Received: 8 August 2019
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Revised: 17 August 2019
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Accepted: 19 August 2019
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Published: 21 August 2019
Rechargeable magnesium ion batteries have recently received considerable attention as an alternative to Li- or Na-ion batteries. Understanding defects and ion transport is a key step in designing high performance electrode materials for Mg-ion batteries. Here we present a classical potential-based atomistic simulation study of defects, dopants and Mg-ion transport in Mg6MnO8. The formation of the Mg–Mn anti-site defect cluster is calculated to be the lowest energy process (1.73 eV/defect). The Mg Frenkel is calculated to be the second most favourable intrinsic defect and its formation energy is 2.84 eV/defect. A three-dimensional long-range Mg-ion migration path with overall activation energy of 0.82 eV is observed, suggesting that the diffusion of Mg-ions in this material is moderate. Substitutional doping of Ga on the Mn site can increase the capacity of this material in the form of Mg interstitials. The most energetically favourable isovalent dopant for Mg is found to be Fe. Interestingly, Si and Ge exhibit exoergic solution enthalpy for doping on the Mn site, requiring experimental verification.
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Keywords:
Mg6MnO8; defects; Mg-ion diffusion; dopants
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MDPI and ACS Style
Kuganathan, N.; Gkanas, E.I.; Chroneos, A. Mg6MnO8 as a Magnesium-Ion Battery Material: Defects, Dopants and Mg-Ion Transport. Energies 2019, 12, 3213. https://doi.org/10.3390/en12173213
AMA Style
Kuganathan N, Gkanas EI, Chroneos A. Mg6MnO8 as a Magnesium-Ion Battery Material: Defects, Dopants and Mg-Ion Transport. Energies. 2019; 12(17):3213. https://doi.org/10.3390/en12173213
Chicago/Turabian StyleKuganathan, Navaratnarajah, Evangelos I. Gkanas, and Alexander Chroneos. 2019. "Mg6MnO8 as a Magnesium-Ion Battery Material: Defects, Dopants and Mg-Ion Transport" Energies 12, no. 17: 3213. https://doi.org/10.3390/en12173213
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