9-13 July 2012
Africa/Johannesburg timezone
<a href="http://events.saip.org.za/internalPage.py?pageId=11&confId=14"><font color=#ff0000>SAIP2012 PROCEEDINGS AVAILABLE</font></a>

First-Principle Study on Stabilities of Reactive Products of Sulphur and Oxygen in Lithium- and Sodium- air Batteries.

11 Jul 2012, 08:00
20m
Oral Presentation Track A - Division for Condensed Matter Physics and Materials DCMPM1

Speaker

Mr CLIFFTON MASEDI (UNIVERSITY OF LIMPOPO)

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

Yes

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

Prof P.E NGOEPE
phuti.ngoepe@ul.ac.za
UNIVERSITY OF LIMPOPO
MATERIALS MODELLING CENTRE

Abstract content <br> &nbsp; (Max 300 words)

Lithium-air batteries are potentially viable ultrahigh energy density chemical power sources, which could potentially offer specific energy up to 3000 Wh/kg being rechargeable. However, the realization of Li-air batteries has a number of difficult problems to overcome, the biggest shortfall exhibited with these systems is the formation of lithium dendrite which raises safety issues. We suggest here to replace the metallic lithium anode by sodium and operate the sodium-air cell, which could enable the development of a new generation of high specific energy rechargeable batteries.
We investigated the stabilities of insoluble discharge products of oxygen and sulphur in the Li-air and Na-air batteries(i.e.Li2O, Li2S, Li2O2, Li2S2 , Na2O, Na2S, Na2O2 and Na2S2 structures) using density functional theory within the generalized gradient approximation. Their structural, mechanical and electronic properties were determined. The lattice parameters were well reproduced and agree to within 2% with the available experimental data. The heats of formation predicts Li2O and Na2O to be the most stable structures whereas Li2S2 and Na2S2 are the least stable which is in good agreement with calculated phonon dispersions. The elastic constants suggest that all the structures are mechanically stable.

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

Yes

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

MSc

Primary author

Mr CLIFFTON MASEDI (UNIVERSITY OF LIMPOPO)

Co-author

Prof. PHUTI NGOEPE (UNIVERSITY OF LIMPOPO)

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