7-11 July 2014
Africa/Johannesburg timezone
<a href="http://events.saip.org.za/internalPage.py?pageId=16&confId=34"><font color=#0000ff>SAIP2014 Proceedings published on 17 April 2015</font></a>

Computational studies of olivine NaMPO<sub>4</sub> (M: Mn, Fe, Co)

8 Jul 2014, 17:10
1h 50m
D Ring ground level

D Ring ground level

Board: A.113
Poster Presentation Track A - Division for Physics of Condensed Matter and Materials Poster1

Speaker

Mr Ndanduleni Lesley Lethole (University of Limpopo)

Would you like to <br> submit a short paper <br> for the Conference <br> Proceedings (Yes / No)?

YES

Apply to be<br> considered for a student <br> &nbsp; award (Yes / No)?

YES

Main supervisor (name and email)<br>and his / her institution

NGOEPE P.E.; phuti.ngoepe@ul.ac.za; UNIVERSITY OF LIMPOPO

Level for award<br>&nbsp;(Hons, MSc, <br> &nbsp; PhD)?

PhD

Abstract content <br> &nbsp; (Max 300 words)<br><a href="http://events.saip.org.za/getFile.py/access?resId=0&materialId=0&confId=34" target="_blank">Formatting &<br>Special chars</a>

Efforts to deal with environmental pollution and exhaustion of oil resources have been the centre of attention throughout the research industry. Hybrid electric vehicles powered by the lithium ion battery have been developed. However, the scarcity of lithium and the possibility of using much safer aqueous electrolytes in sodium ion batteries have shifted interest on sodium ion batteries to ensure sustainability and optimal safety. However, the major drawback for the sodium materials has been their low charge/discharge capacities. Previous studies have shown that NaFePO4 and NaCoPO4 offer charge/discharge capacities of 12 mAh/g and 2.0 mAh/g, respectively, which is very less compare to LiFePO4 (170 mAh/g), LiMnPO4 (70 mAh/g) and LiCoPO4 (70 mAh/g). In this study, we investigate the structural, thermodynamic, electronic and mechanical properties of the olivine NaMPO4 to determine their capabilities as future cathode materials for sodium ion batteries. Calculations have been performed within DFT+U method as implemented in the Vienna Ab initio Simulation Package code. The calculated cell parameters for NaFePO4 and NaCoPO4 were found to be in good agreement to the experimental to within 3%. The heats of formation suggested that NaMnPO4 is the most stable olivine structure, due to the lowest formation energy (-1292 kJ/mol).

Primary author

Mr Ndanduleni Lesley Lethole (University of Limpopo)

Co-authors

Dr Hasani Chauke (Materials Modelling Centre) Prof. Phuti Ngoepe (University of Limpopo)

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