Bulk and surface properties of magnesium peroxide MgO2
| Autor: | Tobit R. Esch, Thomas Bredow |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Reaction formation
Magnesium peroxide Analytical chemistry General Physics and Astronomy chemistry.chemical_element 02 engineering and technology Surfaces and Interfaces General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Oxygen Endothermic process Cathode Surface energy 0104 chemical sciences Surfaces Coatings and Films law.invention chemistry.chemical_compound chemistry law Lattice (order) Interphase 0210 nano-technology |
| Zdroj: | Applied Surface Science. 389:1202-1207 |
| ISSN: | 0169-4332 |
| DOI: | 10.1016/j.apsusc.2016.07.141 |
| Popis: | Magnesium peroxide has been identified in Mg/air batteries as an intermediate in the oxygen reduction reaction (ORR) [1] . It is assumed that MgO 2 is involved in the solid-electrolyte interphase on the cathode surface. Therefore its structure and stability play a crucial role in the performance of Mg/air batteries. In this work we present a theoretical study of the bulk and low-index surface properties of MgO 2 . All methods give a good account of the experimental lattice parameters for MgO 2 and MgO bulk. The reaction energies, enthalpies and free energies for MgO 2 formation from MgO are compared among the different DFT methods and with the local MP2 method. A pronounced dependence from the applied functional is found. At variance with a previous theoretical study but in agreement with recent experiments we find that the MgO 2 formation reaction is endothermic (HSE06-D3BJ: Δ H = 51.9 kJ/mol). The stability of low-index surfaces MgO 2 (001) ( E s = 0.96 J/m 2 ) and (011) ( E s = 1.98 J/m 2 ) is calculated and compared to the surface energy of MgO (001). The formation energy of neutral oxygen vacancies in the topmost layer of the MgO 2 (001) surface is calculated and compared with defect formation energies for MgO (001). |
| Databáze: | OpenAIRE |
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